[{"year":"2026","title":"A modified Levenberg–Marquardt method for estimating the elastic material parameters of polymer waveguides using residuals between autocorrelated frequency responses","date_created":"2026-01-29T08:53:42Z","abstract":[{"lang":"eng","text":"In this contribution, we address the estimation of the frequency-dependent elastic parameters of polymers in the ultrasound range, which is formulated as an inverse problem. This inverse problem is implemented as a nonlinear regression-type optimization problem, in which the simulation signals are fitted to the measurement signals. These signals consist of displacement responses in waveguides, focusing on hollow cylindrical geometries to enhance the simulation efficiency. To accelerate the optimization and reduce the number of model evaluations and wait times, we propose two novel methods. First, we introduce an adaptation of the Levenberg–Marquardt method derived from a geometrical interpretation of the least-squares optimization problem. Second, we introduce an improved objective function based on the autocorrelated envelopes of the measurement and simulation signals. Given that this study primarily relies on simulation data to quantify optimization convergence, we aggregate the expected ranges of realistic material parameters and derive their distributions to ensure the reproducibility of optimizations with proper measurements. We demonstrate the effectiveness of our objective function modification and step adaptation for various materials with isotropic material symmetry by comparing them with the Broyden–Fletcher–Goldfarb–Shanno method. In all cases, our method reduces the total number of model evaluations, thereby shortening the time to identify the material parameters."}],"publication":"Mechanical Systems and Signal Processing","keyword":["Material parameter estimation","Waveguide","Nonlinear optimization","Inverse problem","Least squares"],"language":[{"iso":"eng"}],"page":"113904","intvolume":" 247","citation":{"ama":"Itner D, Dreiling D, Gravenkamp H, Henning B, Birk C. A modified Levenberg–Marquardt method for estimating the elastic material parameters of polymer waveguides using residuals between autocorrelated frequency responses. Mechanical Systems and Signal Processing. 2026;247:113904. doi:https://doi.org/10.1016/j.ymssp.2026.113904","chicago":"Itner, Dominik, Dmitrij Dreiling, Hauke Gravenkamp, Bernd Henning, and Carolin Birk. “A Modified Levenberg–Marquardt Method for Estimating the Elastic Material Parameters of Polymer Waveguides Using Residuals between Autocorrelated Frequency Responses.” Mechanical Systems and Signal Processing 247 (2026): 113904. https://doi.org/10.1016/j.ymssp.2026.113904.","ieee":"D. Itner, D. Dreiling, H. Gravenkamp, B. Henning, and C. Birk, “A modified Levenberg–Marquardt method for estimating the elastic material parameters of polymer waveguides using residuals between autocorrelated frequency responses,” Mechanical Systems and Signal Processing, vol. 247, p. 113904, 2026, doi: https://doi.org/10.1016/j.ymssp.2026.113904.","apa":"Itner, D., Dreiling, D., Gravenkamp, H., Henning, B., & Birk, C. (2026). A modified Levenberg–Marquardt method for estimating the elastic material parameters of polymer waveguides using residuals between autocorrelated frequency responses. Mechanical Systems and Signal Processing, 247, 113904. https://doi.org/10.1016/j.ymssp.2026.113904","bibtex":"@article{Itner_Dreiling_Gravenkamp_Henning_Birk_2026, title={A modified Levenberg–Marquardt method for estimating the elastic material parameters of polymer waveguides using residuals between autocorrelated frequency responses}, volume={247}, DOI={https://doi.org/10.1016/j.ymssp.2026.113904}, journal={Mechanical Systems and Signal Processing}, author={Itner, Dominik and Dreiling, Dmitrij and Gravenkamp, Hauke and Henning, Bernd and Birk, Carolin}, year={2026}, pages={113904} }","mla":"Itner, Dominik, et al. “A Modified Levenberg–Marquardt Method for Estimating the Elastic Material Parameters of Polymer Waveguides Using Residuals between Autocorrelated Frequency Responses.” Mechanical Systems and Signal Processing, vol. 247, 2026, p. 113904, doi:https://doi.org/10.1016/j.ymssp.2026.113904.","short":"D. Itner, D. Dreiling, H. Gravenkamp, B. Henning, C. Birk, Mechanical Systems and Signal Processing 247 (2026) 113904."},"publication_identifier":{"issn":["0888-3270"]},"publication_status":"published","doi":"https://doi.org/10.1016/j.ymssp.2026.113904","main_file_link":[{"open_access":"1","url":"https://www.sciencedirect.com/science/article/pii/S0888327026000610/pdfft?md5=16e8493b44527f4ab0a6d13f634a01c3&pid=1-s2.0-S0888327026000610-main.pdf"}],"oa":"1","date_updated":"2026-02-02T12:44:47Z","volume":247,"author":[{"last_name":"Itner","full_name":"Itner, Dominik","first_name":"Dominik"},{"first_name":"Dmitrij","last_name":"Dreiling","id":"32616","full_name":"Dreiling, Dmitrij"},{"first_name":"Hauke","last_name":"Gravenkamp","full_name":"Gravenkamp, Hauke"},{"last_name":"Henning","full_name":"Henning, Bernd","id":"213","first_name":"Bernd"},{"first_name":"Carolin","last_name":"Birk","full_name":"Birk, Carolin"}],"status":"public","type":"journal_article","_id":"63800","project":[{"name":"Vollständige Bestimmung der akustischen Materialparameter von Polymeren","_id":"89"}],"department":[{"_id":"49"}],"user_id":"32616"},{"abstract":[{"text":"One of the major topics in the modern automotive industry is reducing emissions and increasing the mileage\r\nrange. To tackle this challenge, on the one hand, modifying the powertrain system is a possibility, and on the\r\nother hand, lightweight design offers various possibilities. Multi-Material Design (MMD) involves designing car\r\nbodies that combine different materials that require joining. Given the variety of materials, mechanical joining\r\nprocesses are preferred. Especially the current development of the Giga/Mega-casting process concerning\r\naluminium casting and the subsequent mechanical joining illustrates the challenges of this material group. In car\r\nproduction, aluminium castings are mainly made from aluminium-silicon (AlSi) alloys. Ultimately, the alloy\r\nsystem's insufficient ductility leads to crack initiation during mechanical joining. Cast parts are therefore often\r\nused in areas of the car body that are exposed to high-pressure loads. For example, self-piercing riveting (SPR) is\r\nused due to its high load-bearing capacity. In this study, improved joinability is demonstrated by influencing the\r\nmicrostructure through tailored solidification rates and a developed heat-treatment chain strategy adapted for\r\nhypoeutectic AlSi systems. Data on microstructure, mechanical, and joining properties are used to develop a\r\nsolidification-joining correlation for the SPR process across a range of Si contents and solidification rates. The\r\npurpose is to develop the ability to produce suitable aluminium castings with sufficient joinability, thereby\r\nimproving versatility.","lang":"eng"}],"publication":"Journal of Manufacturing Processes","language":[{"iso":"eng"}],"keyword":["Mechanical joining","Aluminium","Self-piercing riveting","Casting","Microstructure","Joinability AlSi-alloys"],"year":"2026","quality_controlled":"1","title":"Solidification-joinability correlation of hypoeutectic aluminium casting alloys for self-piercing riveting (SPR)","date_created":"2026-02-26T11:21:24Z","publisher":"Elsevier","status":"public","type":"journal_article","funded_apc":"1","article_type":"original","department":[{"_id":"43"},{"_id":"158"},{"_id":"157"},{"_id":"321"}],"user_id":"32340","_id":"64678","project":[{"_id":"131","name":"TRR 285 - Project Area A"},{"_id":"133","name":"TRR 285 - Project Area C"},{"_id":"136","name":"TRR 285 - Subproject A02"},{"name":"TRR 285 - Subproject C02","_id":"146"},{"_id":"130","name":"TRR 285: Methodenentwicklung zur mechanischen Fügbarkeit in wandlungsfähigen Prozessketten"}],"intvolume":" 164","citation":{"short":"M. Neuser, P.K. Kaimann, I. Stratmann, M. Bobbert, J.M.B. Klöckner, M. Mann, K.-P. Hoyer, G. Meschut, M. Schaper, Journal of Manufacturing Processes 164 (2026).","bibtex":"@article{Neuser_Kaimann_Stratmann_Bobbert_Klöckner_Mann_Hoyer_Meschut_Schaper_2026, title={Solidification-joinability correlation of hypoeutectic aluminium casting alloys for self-piercing riveting (SPR)}, volume={164}, DOI={https://doi.org/10.1016/j.jmapro.2026.02.040}, journal={Journal of Manufacturing Processes}, publisher={Elsevier}, author={Neuser, Moritz and Kaimann, Pia Katharina and Stratmann, Ina and Bobbert, Mathias and Klöckner, Johann Moritz Benedikt and Mann, Moritz and Hoyer, Kay-Peter and Meschut, Gerson and Schaper, Mirko}, year={2026} }","mla":"Neuser, Moritz, et al. “Solidification-Joinability Correlation of Hypoeutectic Aluminium Casting Alloys for Self-Piercing Riveting (SPR).” Journal of Manufacturing Processes, vol. 164, Elsevier, 2026, doi:https://doi.org/10.1016/j.jmapro.2026.02.040.","apa":"Neuser, M., Kaimann, P. K., Stratmann, I., Bobbert, M., Klöckner, J. M. B., Mann, M., Hoyer, K.-P., Meschut, G., & Schaper, M. (2026). Solidification-joinability correlation of hypoeutectic aluminium casting alloys for self-piercing riveting (SPR). Journal of Manufacturing Processes, 164. https://doi.org/10.1016/j.jmapro.2026.02.040","ama":"Neuser M, Kaimann PK, Stratmann I, et al. Solidification-joinability correlation of hypoeutectic aluminium casting alloys for self-piercing riveting (SPR). Journal of Manufacturing Processes. 2026;164. doi:https://doi.org/10.1016/j.jmapro.2026.02.040","ieee":"M. Neuser et al., “Solidification-joinability correlation of hypoeutectic aluminium casting alloys for self-piercing riveting (SPR),” Journal of Manufacturing Processes, vol. 164, 2026, doi: https://doi.org/10.1016/j.jmapro.2026.02.040.","chicago":"Neuser, Moritz, Pia Katharina Kaimann, Ina Stratmann, Mathias Bobbert, Johann Moritz Benedikt Klöckner, Moritz Mann, Kay-Peter Hoyer, Gerson Meschut, and Mirko Schaper. “Solidification-Joinability Correlation of Hypoeutectic Aluminium Casting Alloys for Self-Piercing Riveting (SPR).” Journal of Manufacturing Processes 164 (2026). https://doi.org/10.1016/j.jmapro.2026.02.040."},"publication_status":"published","doi":"https://doi.org/10.1016/j.jmapro.2026.02.040","volume":164,"author":[{"first_name":"Moritz","id":"32340","full_name":"Neuser, Moritz","last_name":"Neuser"},{"last_name":"Kaimann","id":"44935","full_name":"Kaimann, Pia Katharina","first_name":"Pia Katharina"},{"first_name":"Ina","full_name":"Stratmann, Ina","last_name":"Stratmann"},{"id":"7850","full_name":"Bobbert, Mathias","last_name":"Bobbert","first_name":"Mathias"},{"first_name":"Johann Moritz Benedikt","last_name":"Klöckner","full_name":"Klöckner, Johann Moritz Benedikt"},{"last_name":"Mann","full_name":"Mann, Moritz","first_name":"Moritz"},{"first_name":"Kay-Peter","last_name":"Hoyer","full_name":"Hoyer, Kay-Peter","id":"48411"},{"id":"32056","full_name":"Meschut, Gerson","last_name":"Meschut","orcid":"0000-0002-2763-1246","first_name":"Gerson"},{"first_name":"Mirko","last_name":"Schaper","id":"43720","full_name":"Schaper, Mirko"}],"date_updated":"2026-02-26T11:22:03Z"},{"publication_identifier":{"issn":["2666-3309"]},"publication_status":"published","intvolume":" 13","citation":{"ieee":"J.-P. Ludwig, E. Tolke, M. C. Schlichter, M. Bobbert, and G. Meschut, “Numerical analysis of the robustness of self-pierce riveting with pre-formed joining partners,” Journal of Advanced Joining Processes, vol. 13, Art. no. 100391, 2026, doi: 10.1016/j.jajp.2026.100391.","chicago":"Ludwig, Jean-Patrick, Emil Tolke, Malte Christian Schlichter, Mathias Bobbert, and Gerson Meschut. “Numerical Analysis of the Robustness of Self-Pierce Riveting with Pre-Formed Joining Partners.” Journal of Advanced Joining Processes 13 (2026). https://doi.org/10.1016/j.jajp.2026.100391.","ama":"Ludwig J-P, Tolke E, Schlichter MC, Bobbert M, Meschut G. Numerical analysis of the robustness of self-pierce riveting with pre-formed joining partners. Journal of Advanced Joining Processes. 2026;13. doi:10.1016/j.jajp.2026.100391","apa":"Ludwig, J.-P., Tolke, E., Schlichter, M. C., Bobbert, M., & Meschut, G. (2026). Numerical analysis of the robustness of self-pierce riveting with pre-formed joining partners. Journal of Advanced Joining Processes, 13, Article 100391. https://doi.org/10.1016/j.jajp.2026.100391","short":"J.-P. Ludwig, E. Tolke, M.C. Schlichter, M. Bobbert, G. Meschut, Journal of Advanced Joining Processes 13 (2026).","bibtex":"@article{Ludwig_Tolke_Schlichter_Bobbert_Meschut_2026, title={Numerical analysis of the robustness of self-pierce riveting with pre-formed joining partners}, volume={13}, DOI={10.1016/j.jajp.2026.100391}, number={100391}, journal={Journal of Advanced Joining Processes}, publisher={Elsevier BV}, author={Ludwig, Jean-Patrick and Tolke, Emil and Schlichter, Malte Christian and Bobbert, Mathias and Meschut, Gerson}, year={2026} }","mla":"Ludwig, Jean-Patrick, et al. “Numerical Analysis of the Robustness of Self-Pierce Riveting with Pre-Formed Joining Partners.” Journal of Advanced Joining Processes, vol. 13, 100391, Elsevier BV, 2026, doi:10.1016/j.jajp.2026.100391."},"volume":13,"author":[{"last_name":"Ludwig","id":"76631","full_name":"Ludwig, Jean-Patrick","first_name":"Jean-Patrick"},{"full_name":"Tolke, Emil","last_name":"Tolke","first_name":"Emil"},{"first_name":"Malte Christian","last_name":"Schlichter","full_name":"Schlichter, Malte Christian","id":"61977"},{"first_name":"Mathias","id":"7850","full_name":"Bobbert, Mathias","last_name":"Bobbert"},{"id":"32056","full_name":"Meschut, Gerson","last_name":"Meschut","orcid":"0000-0002-2763-1246","first_name":"Gerson"}],"date_updated":"2026-03-16T12:38:13Z","doi":"10.1016/j.jajp.2026.100391","type":"journal_article","status":"public","department":[{"_id":"9"}],"user_id":"76631","_id":"64985","project":[{"name":"TRR 285 - Project Area A","_id":"131"},{"_id":"135","name":"TRR 285 - Subproject A01"},{"name":"TRR 285: Methodenentwicklung zur mechanischen Fügbarkeit in wandlungsfähigen Prozessketten","_id":"130"}],"article_number":"100391","quality_controlled":"1","year":"2026","date_created":"2026-03-16T12:30:39Z","publisher":"Elsevier BV","title":"Numerical analysis of the robustness of self-pierce riveting with pre-formed joining partners","publication":"Journal of Advanced Joining Processes","abstract":[{"text":"Modern industrial development has necessitated a wide range of joining technologies. Self-pierce riveting has become a prevalent technique for sheet metal assembly, especially in automotive applications. Achieving proper joint geometry and adequate load-bearing capacity depends on appropriate tool selection and precise process control. Material properties and condition also play a significant role in process performance. To accommodate the inevitable variations in component characteristics during production, a robust and stable joining process is essential. The study focuses on investigating the influence of preformed joining partners on the joining process and the joint's load capacity. An EN AW-6014 in T4 condition, as well as an HCT590X, are used as materials for this study. For this purpose, an exemplary process chain consisting of the steps of performing, joining, and shear load testing is studied. Each process step is implemented using an FE model to predict the outcome of subsequent steps. For analysis of the influence of pre-strain, an optimisation software is used to plan and execute variations of the process. These variations are used to create a meta-model that can describe the relationships between pre-forming and characteristic parameters of subsequent process steps. The resulting model is validated by comparing simulation and experimental data. Finally, in a novel approach, the robustness of the presented process chain is analyzed in terms of a tolerable performance level for the joining partners.","lang":"eng"}],"language":[{"iso":"eng"}],"keyword":["Self-pierce riveting","FE modelling","Plastic pre-deformation","Meta modelling"]},{"citation":{"chicago":"Wohnhas, Verena, Phillip Neumann, and Birgit Lütje-Klose. “Zeit für Arbeitszufriedenheit? Eine quantitativ-empirische Studie zur Bedeutung fester Kooperationszeiten für die Arbeitszufriedenheit von Lehrkräften in inklusiven Schulen.” QfI - Qualifizierung für Inklusion. Online-Zeitschrift zur Forschung über Aus-, Fort- und Weiterbildung pädagogischer Fachkräfte 6, no. 2 (2025). https://doi.org/10.21248/qfi.167.","ieee":"V. Wohnhas, P. Neumann, and B. Lütje-Klose, “Zeit für Arbeitszufriedenheit? Eine quantitativ-empirische Studie zur Bedeutung fester Kooperationszeiten für die Arbeitszufriedenheit von Lehrkräften in inklusiven Schulen,” QfI - Qualifizierung für Inklusion. Online-Zeitschrift zur Forschung über Aus-, Fort- und Weiterbildung pädagogischer Fachkräfte, vol. 6, no. 2, 2025, doi: 10.21248/qfi.167.","ama":"Wohnhas V, Neumann P, Lütje-Klose B. Zeit für Arbeitszufriedenheit? Eine quantitativ-empirische Studie zur Bedeutung fester Kooperationszeiten für die Arbeitszufriedenheit von Lehrkräften in inklusiven Schulen. QfI - Qualifizierung für Inklusion Online-Zeitschrift zur Forschung über Aus-, Fort- und Weiterbildung pädagogischer Fachkräfte. 2025;6(2). doi:10.21248/qfi.167","apa":"Wohnhas, V., Neumann, P., & Lütje-Klose, B. (2025). Zeit für Arbeitszufriedenheit? Eine quantitativ-empirische Studie zur Bedeutung fester Kooperationszeiten für die Arbeitszufriedenheit von Lehrkräften in inklusiven Schulen. QfI - Qualifizierung für Inklusion. Online-Zeitschrift zur Forschung über Aus-, Fort- und Weiterbildung pädagogischer Fachkräfte, 6(2). https://doi.org/10.21248/qfi.167","mla":"Wohnhas, Verena, et al. “Zeit für Arbeitszufriedenheit? Eine quantitativ-empirische Studie zur Bedeutung fester Kooperationszeiten für die Arbeitszufriedenheit von Lehrkräften in inklusiven Schulen.” QfI - Qualifizierung für Inklusion. Online-Zeitschrift zur Forschung über Aus-, Fort- und Weiterbildung pädagogischer Fachkräfte, vol. 6, no. 2, University Library J. C. Senckenberg, 2025, doi:10.21248/qfi.167.","short":"V. Wohnhas, P. Neumann, B. Lütje-Klose, QfI - Qualifizierung für Inklusion. Online-Zeitschrift zur Forschung über Aus-, Fort- und Weiterbildung pädagogischer Fachkräfte 6 (2025).","bibtex":"@article{Wohnhas_Neumann_Lütje-Klose_2025, title={Zeit für Arbeitszufriedenheit? Eine quantitativ-empirische Studie zur Bedeutung fester Kooperationszeiten für die Arbeitszufriedenheit von Lehrkräften in inklusiven Schulen}, volume={6}, DOI={10.21248/qfi.167}, number={2}, journal={QfI - Qualifizierung für Inklusion. Online-Zeitschrift zur Forschung über Aus-, Fort- und Weiterbildung pädagogischer Fachkräfte}, publisher={University Library J. C. Senckenberg}, author={Wohnhas, Verena and Neumann, Phillip and Lütje-Klose, Birgit}, year={2025} }"},"intvolume":" 6","publication_status":"published","publication_identifier":{"issn":["2699-2477"]},"main_file_link":[{"url":"https://www.qfi-oz.de/index.php/inklusion/article/view/167","open_access":"1"}],"doi":"10.21248/qfi.167","author":[{"first_name":"Verena","full_name":"Wohnhas, Verena","last_name":"Wohnhas"},{"first_name":"Phillip","last_name":"Neumann","id":"95559","full_name":"Neumann, Phillip"},{"full_name":"Lütje-Klose, Birgit","last_name":"Lütje-Klose","first_name":"Birgit"}],"volume":6,"date_updated":"2025-04-29T08:31:28Z","oa":"1","status":"public","type":"journal_article","alternative_title":["Time for job satisfaction? A quantitative-empirical study on the significance of fixed cooperation times for the job satisfaction of teachers in inclusive schools"],"article_type":"original","user_id":"95559","department":[{"_id":"854"}],"_id":"59708","year":"2025","issue":"2","title":"Zeit für Arbeitszufriedenheit? Eine quantitativ-empirische Studie zur Bedeutung fester Kooperationszeiten für die Arbeitszufriedenheit von Lehrkräften in inklusiven Schulen","date_created":"2025-04-29T08:14:03Z","publisher":"University Library J. C. Senckenberg","abstract":[{"lang":"ger","text":"Die Arbeitszufriedenheit von Lehrkräften gilt als zentrale Komponente für die Qualität des Bil­dungssystems. In inklusiven Schulen müssen Regelschullehrkräfte und sonderpädagogische Lehrkräfte kooperieren, um allen Schüler:innen eine bestmögliche Förderung zu gewährleisten. Dazu benötigen sie jedoch Zeitfenster, die von vielen Lehrkräften als nicht ausreichend benannt werden. Ziel des vorliegenden Beitrags ist es, empirisch zu untersuchen, welche Bedeutung festen Zeitfenstern für die Lehrkräftekooperation im Klassenteam, im Jahrgangsteam und im Fachteam für die Arbeitszufriedenheit zukommt. Weiterhin soll überprüft werden, ob Teile der Zusammenhänge über die Zufriedenheit mit der Kooperationshäufigkeit und die kollektive Selbstwirksamkeitsüberzeugung der Lehrkräfte erklärt werden können. Dazu werden Daten aus dem BMBF-geförderten Projekt BiFoKi mit N=194 Lehrkräften und N=28 Schulleitungen analy­siert. Die Ergebnisse zeigen, dass feste Zeitfenster für die Kooperation in den unterschiedlichen Teams mit einer erhöhten Arbeitszufriedenheit im Zusammenhang stehen und in Teilen über die kollektive Selbstwirksamkeitsüberzeugung mediiert werden."},{"text":"The job satisfaction of teachers is considered a central component for the quality of the educa­tion system. In inclusive schools, regular school teachers and special needs teachers must co­operate in order to ensure that all pupils receive the best possible support. To do this, however, they need time slots that many teachers say are not sufficient. The aim of this article is to em­pirically investigate the importance of fixed time slots for teacher cooperation in the class team, the year team and the expert team for job satisfaction. Furthermore, it will be examined whether parts of the correlations can be explained by satisfaction with the frequency of cooperation and the teachers' collective self-efficacy expectations. To this end, data from the BMBF-funded BiFoKi project with N=194 teachers and N=28 head teachers will be analyzed. The results show that fixed time slots for cooperation in the different teams are associated with increased job satisfaction and are mediated in part by collective self-efficacy expectations.","lang":"eng"}],"publication":"QfI - Qualifizierung für Inklusion. Online-Zeitschrift zur Forschung über Aus-, Fort- und Weiterbildung pädagogischer Fachkräfte","language":[{"iso":"ger"}],"keyword":["Arbeitszufriedenheit","Inklusion","Sonderpädagogik","Kooperation","Selbstwirksamkeit","Schulentwicklung","job satisfaction","Inclusion","Special Education","Self-efficacy","school development"]},{"publication":"44th Conference of the International Deep Drawing Research Group (IDDRG 2025)","abstract":[{"lang":"eng","text":"Lightweight design is a driving concept in modern automotive engineering to minimize resource consumption over a vehicle's lifecycle through multi-material design, which relies on the use of joining techniques in car body fabrication. Multi-material design and the increasing trend towards producing large structural components using the megacasting process pose considerable challenges, particularly in the mechanical joining of aluminium-silicon (AlSi) castings. These castings typically exhibit low ductility and are prone to cracking when mechanically joined. Based on the excellent castability of hypoeutectic AlSi alloys, these are applied in sand casting and die casting as well as in megacasting. With a silicon content between 7 wt% and 12 wt%, these AlSi-alloys have a plate-like silicon phase that initiates cracks during mechanical joining. To enhance the joinability of castings, the research hypothesis is that improved solidification conditions enable a significant modification in the microstructure and therefore, increase the mechanical properties. During the manufacture of the castings using the sand casting process, the solidification conditions within the structural elements are varied to modify the microstructure to obtain castings with graded microstructure. The castings are evaluated using mechanical, microstructural and joining testing methods and finally, a microstructure-joinability correlation is established."}],"keyword":["Joining","Casting","Self-pierce riveting","Aluminium casting alloy"],"language":[{"iso":"eng"}],"quality_controlled":"1","year":"2025","date_created":"2025-05-12T15:21:06Z","title":"Mechanical joinability of microstructurally graded structural components manufactured from hypoeutectic aluminium casting alloys","type":"journal_article","status":"public","_id":"59872","project":[{"name":"TRR 285 - A: TRR 285 - Project Area A","_id":"131"},{"name":"TRR 285 – A02: TRR 285 - Subproject A02","_id":"136"},{"_id":"135","name":"TRR 285 – A01: TRR 285 - Subproject A01"},{"name":"TRR 285: Methodenentwicklung zur mechanischen Fügbarkeit in wandlungsfähigen Prozessketten","_id":"130"}],"department":[{"_id":"43"},{"_id":"158"},{"_id":"157"},{"_id":"9"},{"_id":"321"}],"user_id":"7850","article_type":"original","article_number":"01081","publication_status":"published","intvolume":" 408","citation":{"bibtex":"@article{Neuser_Schlichter_Hoyer_Bobbert_Meschut_Schaper_2025, title={Mechanical joinability of microstructurally graded structural components manufactured from hypoeutectic aluminium casting alloys}, volume={408}, DOI={10.1051/matecconf/202540801081}, number={01081}, journal={44th Conference of the International Deep Drawing Research Group (IDDRG 2025)}, author={Neuser, Moritz and Schlichter, Malte Christian and Hoyer, Kay-Peter and Bobbert, Mathias and Meschut, Gerson and Schaper, Mirko}, year={2025} }","mla":"Neuser, Moritz, et al. “Mechanical Joinability of Microstructurally Graded Structural Components Manufactured from Hypoeutectic Aluminium Casting Alloys.” 44th Conference of the International Deep Drawing Research Group (IDDRG 2025), vol. 408, 01081, 2025, doi:10.1051/matecconf/202540801081.","short":"M. Neuser, M.C. Schlichter, K.-P. Hoyer, M. Bobbert, G. Meschut, M. Schaper, 44th Conference of the International Deep Drawing Research Group (IDDRG 2025) 408 (2025).","ama":"Neuser M, Schlichter MC, Hoyer K-P, Bobbert M, Meschut G, Schaper M. Mechanical joinability of microstructurally graded structural components manufactured from hypoeutectic aluminium casting alloys. 44th Conference of the International Deep Drawing Research Group (IDDRG 2025). 2025;408. doi:10.1051/matecconf/202540801081","apa":"Neuser, M., Schlichter, M. C., Hoyer, K.-P., Bobbert, M., Meschut, G., & Schaper, M. (2025). Mechanical joinability of microstructurally graded structural components manufactured from hypoeutectic aluminium casting alloys. 44th Conference of the International Deep Drawing Research Group (IDDRG 2025), 408, Article 01081. https://doi.org/10.1051/matecconf/202540801081","ieee":"M. Neuser, M. C. Schlichter, K.-P. Hoyer, M. Bobbert, G. Meschut, and M. Schaper, “Mechanical joinability of microstructurally graded structural components manufactured from hypoeutectic aluminium casting alloys,” 44th Conference of the International Deep Drawing Research Group (IDDRG 2025), vol. 408, Art. no. 01081, 2025, doi: 10.1051/matecconf/202540801081.","chicago":"Neuser, Moritz, Malte Christian Schlichter, Kay-Peter Hoyer, Mathias Bobbert, Gerson Meschut, and Mirko Schaper. “Mechanical Joinability of Microstructurally Graded Structural Components Manufactured from Hypoeutectic Aluminium Casting Alloys.” 44th Conference of the International Deep Drawing Research Group (IDDRG 2025) 408 (2025). https://doi.org/10.1051/matecconf/202540801081."},"oa":"1","date_updated":"2026-02-24T13:41:58Z","volume":408,"author":[{"first_name":"Moritz","last_name":"Neuser","full_name":"Neuser, Moritz","id":"32340"},{"first_name":"Malte Christian","full_name":"Schlichter, Malte Christian","id":"61977","last_name":"Schlichter"},{"first_name":"Kay-Peter","last_name":"Hoyer","id":"48411","full_name":"Hoyer, Kay-Peter"},{"full_name":"Bobbert, Mathias","id":"7850","last_name":"Bobbert","first_name":"Mathias"},{"first_name":"Gerson","id":"32056","full_name":"Meschut, Gerson","orcid":"0000-0002-2763-1246","last_name":"Meschut"},{"first_name":"Mirko","last_name":"Schaper","id":"43720","full_name":"Schaper, Mirko"}],"doi":"10.1051/matecconf/202540801081","conference":{"end_date":"2025-06-05","location":"Lissabon (Portugal)","name":"44th Conference of the International Deep Drawing Research Group (IDDRG 2025)","start_date":"2025-06-02"},"main_file_link":[{"url":"\thttps://doi.org/10.1051/matecconf/202540801081","open_access":"1"}]},{"project":[{"_id":"133","name":"TRR 285 - Project Area C"},{"name":"TRR 285 - Subproject C04","_id":"148"},{"_id":"130","name":"TRR 285: Methodenentwicklung zur mechanischen Fügbarkeit in wandlungsfähigen Prozessketten"},{"_id":"131","name":"TRR 285 - Project Area A"},{"_id":"137","name":"TRR 285 - Subproject A03"},{"name":"TRR 285 - Subproject A01","_id":"135"}],"_id":"61149","user_id":"105344","type":"conference","editor":[{"first_name":"J.F. Silva","last_name":"Gomes","full_name":"Gomes, J.F. Silva"},{"last_name":"Meguid","full_name":"Meguid, Shaker A.","first_name":"Shaker A."}],"status":"public","date_updated":"2026-02-27T06:45:17Z","oa":"1","author":[{"last_name":"Dargel","id":"114764","full_name":"Dargel, Alrik","first_name":"Alrik"},{"last_name":"Gröger","full_name":"Gröger, Benjamin","first_name":"Benjamin"},{"first_name":"Malte Christian","last_name":"Schlichter","id":"61977","full_name":"Schlichter, Malte Christian"},{"orcid":"0000-0002-0169-8602","last_name":"Gerritzen","id":"105344","full_name":"Gerritzen, Johannes","first_name":"Johannes"},{"id":"83408","full_name":"Köhler, Daniel","last_name":"Köhler","first_name":"Daniel"},{"last_name":"Meschut","orcid":"0000-0002-2763-1246","id":"32056","full_name":"Meschut, Gerson","first_name":"Gerson"},{"first_name":"Maik","full_name":"Gude, Maik","last_name":"Gude"},{"first_name":"Robert","full_name":"Kupfer, Robert","last_name":"Kupfer"}],"main_file_link":[{"open_access":"1","url":"https://www.researchgate.net/publication/395593556_LOCAL_DEFORMATION_AND_FAILURE_OF_COMPOSITES_DURING_SELF-PIERCING_RIVETING_A_CT_BASED_MICROSTRUCTURE_INVESTIGATION"}],"doi":"10.24840/978-972-752-323-8","conference":{"end_date":"2025-07-18","location":"Porto","name":"8th International Conference on Integrity-Reliability-Failure (IRF2025)","start_date":"2025-07-15"},"publication_status":"published","publication_identifier":{"isbn":["9789727523238"]},"place":"Porto","citation":{"chicago":"Dargel, Alrik, Benjamin Gröger, Malte Christian Schlichter, Johannes Gerritzen, Daniel Köhler, Gerson Meschut, Maik Gude, and Robert Kupfer. “LOCAL DEFORMATION AND FAILURE OF COMPOSITES DURING SELF-PIERCING RIVETING: A CT BASED MICROSTRUCTURE INVESTIGATION.” In Proceedings of the 8th International Conference on Integrity-Reliability-Failure (IRF2025), edited by J.F. Silva Gomes and Shaker A. Meguid. Porto: FEUP, 2025. https://doi.org/10.24840/978-972-752-323-8.","ieee":"A. Dargel et al., “LOCAL DEFORMATION AND FAILURE OF COMPOSITES DURING SELF-PIERCING RIVETING: A CT BASED MICROSTRUCTURE INVESTIGATION,” in Proceedings of the 8th International Conference on Integrity-Reliability-Failure (IRF2025), Porto, 2025, doi: 10.24840/978-972-752-323-8.","apa":"Dargel, A., Gröger, B., Schlichter, M. C., Gerritzen, J., Köhler, D., Meschut, G., Gude, M., & Kupfer, R. (2025). LOCAL DEFORMATION AND FAILURE OF COMPOSITES DURING SELF-PIERCING RIVETING: A CT BASED MICROSTRUCTURE INVESTIGATION. In J. F. S. Gomes & S. A. Meguid (Eds.), Proceedings of the 8th International Conference on Integrity-Reliability-Failure (IRF2025). FEUP. https://doi.org/10.24840/978-972-752-323-8","ama":"Dargel A, Gröger B, Schlichter MC, et al. LOCAL DEFORMATION AND FAILURE OF COMPOSITES DURING SELF-PIERCING RIVETING: A CT BASED MICROSTRUCTURE INVESTIGATION. In: Gomes JFS, Meguid SA, eds. Proceedings of the 8th International Conference on Integrity-Reliability-Failure (IRF2025). FEUP; 2025. doi:10.24840/978-972-752-323-8","short":"A. Dargel, B. Gröger, M.C. Schlichter, J. Gerritzen, D. Köhler, G. Meschut, M. Gude, R. Kupfer, in: J.F.S. Gomes, S.A. Meguid (Eds.), Proceedings of the 8th International Conference on Integrity-Reliability-Failure (IRF2025), FEUP, Porto, 2025.","bibtex":"@inproceedings{Dargel_Gröger_Schlichter_Gerritzen_Köhler_Meschut_Gude_Kupfer_2025, place={Porto}, title={LOCAL DEFORMATION AND FAILURE OF COMPOSITES DURING SELF-PIERCING RIVETING: A CT BASED MICROSTRUCTURE INVESTIGATION}, DOI={10.24840/978-972-752-323-8}, booktitle={Proceedings of the 8th International Conference on Integrity-Reliability-Failure (IRF2025)}, publisher={FEUP}, author={Dargel, Alrik and Gröger, Benjamin and Schlichter, Malte Christian and Gerritzen, Johannes and Köhler, Daniel and Meschut, Gerson and Gude, Maik and Kupfer, Robert}, editor={Gomes, J.F. Silva and Meguid, Shaker A.}, year={2025} }","mla":"Dargel, Alrik, et al. “LOCAL DEFORMATION AND FAILURE OF COMPOSITES DURING SELF-PIERCING RIVETING: A CT BASED MICROSTRUCTURE INVESTIGATION.” Proceedings of the 8th International Conference on Integrity-Reliability-Failure (IRF2025), edited by J.F. Silva Gomes and Shaker A. Meguid, FEUP, 2025, doi:10.24840/978-972-752-323-8."},"keyword":["self-piercing riveting","computed tomography","thermoplastic composites","process-structure-interaction"],"language":[{"iso":"eng"}],"publication":"Proceedings of the 8th International Conference on Integrity-Reliability-Failure (IRF2025)","abstract":[{"text":"The use of continuous fiber-reinforced thermoplastics (FRTP) in automotive industry increases due to their excellent material properties and possibility of rapid processing. The scale spanning heterogeneity of their material structure and its influence on the material behavior, however, presents significant challenges for most joining technologies, such as self-piercing riveting (SPR). During mechanical joining, the material structure is significantly altered within and around the joining zone, heavily influencing the material behavior. A comprehensive understanding of the underlying phenomena of material alteration during the SPR process is essential as basis for validating numerical simulations. This study examines the material structure at ten stages of a step-setting test of SPR with two FRTP sheets with glass-fiber reinforcement. Utilizing X-ray computed tomography (CT), the damage phenomena within different areas of the setting test are analyzed three-dimensionally and key parameters are quantified. Dominating phenomena during the penetration of the rivet into the laminate are fiber failure (FF), interfiber failure (IFF) and fiber bending, while delamination, fiber kinking and roving splitting are also observed. At the final stages, the bottom layers of the second sheet collapse and form a bulge into the cavity of the die.","lang":"eng"}],"publisher":"FEUP","date_created":"2025-09-08T11:52:45Z","title":"LOCAL DEFORMATION AND FAILURE OF COMPOSITES DURING SELF-PIERCING RIVETING: A CT BASED MICROSTRUCTURE INVESTIGATION","year":"2025"},{"language":[{"iso":"eng"}],"keyword":["aluminium","casting","microstructure","joinability","self-piercing riveting"],"abstract":[{"lang":"eng","text":"One of the most important strategies for reducing CO2 emissions in the mobility sector is lightweight construction. In particular, the car body offers several opportunities for weight reduction. Multi-material designs are increasingly being applied to select the most suitable material for the respective load and ultimately achieve synergy effects. For example, aluminium castings are used at the nodes of a spaceframe body. Subsequently, these are joined with profiles to form the bodyshell. To join different materials mechanical joining techniques, such as semi-tubular self-piercing riveting, are deployed. According to the current state of the art, cracks occur in the aluminium castings during the mechanical joining process as a result of the high degree of deformation. Although the aluminium casting alloys of the AlSi-system exhibit low ductility, these alloys reveal excellent castability. In particular, the ability to cast thin structural parts is enabled by the low liquidus point of the near eutectic aluminium casting alloys.\r\nThis study addresses the mechanical joining properties of the near eutectic aluminium casting alloy AlSi12, depending on different microstructures. These are achieved by annealing processes and modifying agents. Through an adapted heat treatment, the previously lamellar morphology can be transformed into a globular morphology, which leads to increased ductility and prevents the formation of cracks during the self-piercing riveting (SPR). The joinability is investigated using different die geometries, whereas the joint formation is analysed regarding crack initiation. To evaluate the increased ductility, microstructural and mechanical tests are performed and finally, a microstructure-joinability correlation is established."}],"publication":"The Journal of Materials: Design and Applications, Part L","title":"Mechanical properties and joinability of the near-eutectic aluminium casting alloy AlSi12","date_created":"2025-02-24T10:25:31Z","publisher":"Sage Publications","year":"2025","quality_controlled":"1","article_type":"original","user_id":"32340","department":[{"_id":"43"},{"_id":"158"},{"_id":"157"},{"_id":"9"},{"_id":"321"}],"project":[{"name":"TRR 285 - A: TRR 285 - Project Area A","_id":"131"},{"_id":"136","name":"TRR 285 – A02: TRR 285 - Subproject A02"},{"name":"TRR 285 - C: TRR 285 - Project Area C","_id":"133"},{"_id":"146","name":"TRR 285 – C02: TRR 285 - Subproject C02"}],"_id":"58807","status":"public","type":"journal_article","conference":{"end_date":"2024-07-05","location":"Porto, Portugal","name":"5th International Conference on Materials Design and Applications 2024","start_date":"2024-07-04"},"doi":"10.1177/14644207251319922","author":[{"id":"32340","full_name":"Neuser, Moritz","last_name":"Neuser","first_name":"Moritz"},{"first_name":"Pia Katharina","last_name":"Holtkamp","full_name":"Holtkamp, Pia Katharina","id":"44935"},{"first_name":"Kay-Peter","full_name":"Hoyer, Kay-Peter","id":"48411","last_name":"Hoyer"},{"first_name":"Fabian","last_name":"Kappe","id":"66459","full_name":"Kappe, Fabian"},{"full_name":"Yildiz, Safak","last_name":"Yildiz","first_name":"Safak"},{"first_name":"Mathias","id":"7850","full_name":"Bobbert, Mathias","last_name":"Bobbert"},{"first_name":"Gerson","orcid":"0000-0002-2763-1246","last_name":"Meschut","full_name":"Meschut, Gerson","id":"32056"},{"first_name":"Mirko","id":"43720","full_name":"Schaper, Mirko","last_name":"Schaper"}],"date_updated":"2025-02-24T12:25:04Z","citation":{"chicago":"Neuser, Moritz, Pia Katharina Holtkamp, Kay-Peter Hoyer, Fabian Kappe, Safak Yildiz, Mathias Bobbert, Gerson Meschut, and Mirko Schaper. “Mechanical Properties and Joinability of the Near-Eutectic Aluminium Casting Alloy AlSi12.” The Journal of Materials: Design and Applications, Part L, 2025. https://doi.org/10.1177/14644207251319922.","ieee":"M. Neuser et al., “Mechanical properties and joinability of the near-eutectic aluminium casting alloy AlSi12,” The Journal of Materials: Design and Applications, Part L, 2025, doi: 10.1177/14644207251319922.","ama":"Neuser M, Holtkamp PK, Hoyer K-P, et al. Mechanical properties and joinability of the near-eutectic aluminium casting alloy AlSi12. The Journal of Materials: Design and Applications, Part L. Published online 2025. doi:10.1177/14644207251319922","short":"M. Neuser, P.K. Holtkamp, K.-P. Hoyer, F. Kappe, S. Yildiz, M. Bobbert, G. Meschut, M. Schaper, The Journal of Materials: Design and Applications, Part L (2025).","bibtex":"@article{Neuser_Holtkamp_Hoyer_Kappe_Yildiz_Bobbert_Meschut_Schaper_2025, title={Mechanical properties and joinability of the near-eutectic aluminium casting alloy AlSi12}, DOI={10.1177/14644207251319922}, journal={The Journal of Materials: Design and Applications, Part L}, publisher={Sage Publications}, author={Neuser, Moritz and Holtkamp, Pia Katharina and Hoyer, Kay-Peter and Kappe, Fabian and Yildiz, Safak and Bobbert, Mathias and Meschut, Gerson and Schaper, Mirko}, year={2025} }","mla":"Neuser, Moritz, et al. “Mechanical Properties and Joinability of the Near-Eutectic Aluminium Casting Alloy AlSi12.” The Journal of Materials: Design and Applications, Part L, Sage Publications, 2025, doi:10.1177/14644207251319922.","apa":"Neuser, M., Holtkamp, P. K., Hoyer, K.-P., Kappe, F., Yildiz, S., Bobbert, M., Meschut, G., & Schaper, M. (2025). Mechanical properties and joinability of the near-eutectic aluminium casting alloy AlSi12. The Journal of Materials: Design and Applications, Part L. 5th International Conference on Materials Design and Applications 2024, Porto, Portugal. https://doi.org/10.1177/14644207251319922"},"publication_status":"published","has_accepted_license":"1"},{"_id":"60290","project":[{"_id":"131","name":"TRR 285 - A: TRR 285 - Project Area A"},{"name":"TRR 285 – A04: TRR 285 - Subproject A04","_id":"138"},{"_id":"133","name":"TRR 285 - C: TRR 285 - Project Area C"},{"_id":"146","name":"TRR 285 – C02: TRR 285 - Subproject C02"}],"department":[{"_id":"630"},{"_id":"43"},{"_id":"157"}],"series_title":"Sheet Metal 2025","user_id":"44935","extern":"1","type":"conference","editor":[{"last_name":"Meschut","full_name":"Meschut, Gerson","first_name":"Gerson"},{"full_name":"Bobbert, Mathias","last_name":"Bobbert","first_name":"Mathias"},{"full_name":"Duflou, Joost","last_name":"Duflou","first_name":"Joost"},{"full_name":"Fratini, Livan","last_name":"Fratini","first_name":"Livan"},{"first_name":"Hinnerk","last_name":"Hagenah","full_name":"Hagenah, Hinnerk"},{"full_name":"Martins, Paulo A. F.","last_name":"Martins","first_name":"Paulo A. F."},{"last_name":"Merklein","full_name":"Merklein, Marion","first_name":"Marion"},{"first_name":"Fabrizio","last_name":"Micari","full_name":"Micari, Fabrizio"}],"status":"public","date_updated":"2025-06-27T08:19:26Z","volume":52,"author":[{"last_name":"Lüder","full_name":"Lüder, Stephan","first_name":"Stephan"},{"first_name":"Pia Katharina","last_name":"Holtkamp","id":"44935","full_name":"Holtkamp, Pia Katharina"},{"last_name":"Wituschek","full_name":"Wituschek, Simon","first_name":"Simon"},{"first_name":"Mathias","id":"7850","full_name":"Bobbert, Mathias","last_name":"Bobbert"},{"first_name":"Gerson","orcid":"0000-0002-2763-1246","last_name":"Meschut","id":"32056","full_name":"Meschut, Gerson"},{"full_name":"Lechner, Michael","last_name":"Lechner","first_name":"Michael"},{"last_name":"Schmale","full_name":"Schmale, Hans Christian","first_name":"Hans Christian"}],"doi":"10.21741/9781644903551-13","conference":{"start_date":"2025-04-01","name":"21st International Conference on Sheet Metal","location":"Paderborn","end_date":"2025-04-03"},"publication_identifier":{"issn":["2474-395X"]},"publication_status":"published","place":"Millersville","page":"101 - 108","intvolume":" 52","citation":{"ieee":"S. Lüder et al., “Analysis of the binding mechanisms depending on versatile process variants of self-piercing riveting,” in Materials Research Proceedings, Paderborn, 2025, vol. 52, pp. 101–108, doi: 10.21741/9781644903551-13.","chicago":"Lüder, Stephan, Pia Katharina Holtkamp, Simon Wituschek, Mathias Bobbert, Gerson Meschut, Michael Lechner, and Hans Christian Schmale. “Analysis of the Binding Mechanisms Depending on Versatile Process Variants of Self-Piercing Riveting.” In Materials Research Proceedings, edited by Gerson Meschut, Mathias Bobbert, Joost Duflou, Livan Fratini, Hinnerk Hagenah, Paulo A. F. Martins, Marion Merklein, and Fabrizio Micari, 52:101–8. Sheet Metal 2025. Millersville: Materials Research Forum LLC, 2025. https://doi.org/10.21741/9781644903551-13.","ama":"Lüder S, Holtkamp PK, Wituschek S, et al. Analysis of the binding mechanisms depending on versatile process variants of self-piercing riveting. In: Meschut G, Bobbert M, Duflou J, et al., eds. Materials Research Proceedings. Vol 52. Sheet Metal 2025. Materials Research Forum LLC; 2025:101-108. doi:10.21741/9781644903551-13","mla":"Lüder, Stephan, et al. “Analysis of the Binding Mechanisms Depending on Versatile Process Variants of Self-Piercing Riveting.” Materials Research Proceedings, edited by Gerson Meschut et al., vol. 52, Materials Research Forum LLC, 2025, pp. 101–08, doi:10.21741/9781644903551-13.","bibtex":"@inproceedings{Lüder_Holtkamp_Wituschek_Bobbert_Meschut_Lechner_Schmale_2025, place={Millersville}, series={Sheet Metal 2025}, title={Analysis of the binding mechanisms depending on versatile process variants of self-piercing riveting}, volume={52}, DOI={10.21741/9781644903551-13}, booktitle={Materials Research Proceedings}, publisher={Materials Research Forum LLC}, author={Lüder, Stephan and Holtkamp, Pia Katharina and Wituschek, Simon and Bobbert, Mathias and Meschut, Gerson and Lechner, Michael and Schmale, Hans Christian}, editor={Meschut, Gerson and Bobbert, Mathias and Duflou, Joost and Fratini, Livan and Hagenah, Hinnerk and Martins, Paulo A. F. and Merklein, Marion and Micari, Fabrizio}, year={2025}, pages={101–108}, collection={Sheet Metal 2025} }","short":"S. Lüder, P.K. Holtkamp, S. Wituschek, M. Bobbert, G. Meschut, M. Lechner, H.C. Schmale, in: G. Meschut, M. Bobbert, J. Duflou, L. Fratini, H. Hagenah, P.A.F. Martins, M. Merklein, F. Micari (Eds.), Materials Research Proceedings, Materials Research Forum LLC, Millersville, 2025, pp. 101–108.","apa":"Lüder, S., Holtkamp, P. K., Wituschek, S., Bobbert, M., Meschut, G., Lechner, M., & Schmale, H. C. (2025). Analysis of the binding mechanisms depending on versatile process variants of self-piercing riveting. In G. Meschut, M. Bobbert, J. Duflou, L. Fratini, H. Hagenah, P. A. F. Martins, M. Merklein, & F. Micari (Eds.), Materials Research Proceedings (Vol. 52, pp. 101–108). Materials Research Forum LLC. https://doi.org/10.21741/9781644903551-13"},"keyword":["Joining","Self-Piercing Riveting","Sheet Metal"],"language":[{"iso":"eng"}],"publication":"Materials Research Proceedings","abstract":[{"text":"The constantly increasing demand for climate protection and resource conservation requires innovative and versatile joining processes that improve adaptability to the joining task and robustness to enable flexible manufacturing on a production line. Therefore, the versatile SPR (V-SPR) and tumbling SPR (T-SPR) were developed. Using the example of a mixed material combination HCT590X+Z (t0 = 1.0 mm) / EN AW-6014 T4 (t0 = 2.0 mm), these processes were examined and compared with regard to the binding mechanisms form closure and force closure using micrographs, non-destructive resistance measurements and destructive torsion tests. For this purpose, a new sample geometry was defined, and the methods were adapted to the SPR process variants.","lang":"eng"}],"publisher":"Materials Research Forum LLC","date_created":"2025-06-20T10:13:22Z","title":"Analysis of the binding mechanisms depending on versatile process variants of self-piercing riveting","quality_controlled":"1","year":"2025"},{"oa":"1","date_updated":"2025-10-16T11:56:36Z","author":[{"first_name":"Radu Ioan","last_name":"Bot","full_name":"Bot, Radu Ioan"},{"first_name":"Konstantin","orcid":"https://orcid.org/0000-0003-3384-3496","last_name":"Sonntag","full_name":"Sonntag, Konstantin","id":"56399"}],"main_file_link":[{"url":"https://arxiv.org/pdf/2411.18422"}],"has_accepted_license":"1","citation":{"short":"R.I. Bot, K. Sonntag, Journal of Mathematical Analysis and Applications (2025).","bibtex":"@article{Bot_Sonntag_2025, title={Inertial dynamics with vanishing Tikhonov regularization for multobjective optimization}, journal={Journal of Mathematical Analysis and Applications}, author={Bot, Radu Ioan and Sonntag, Konstantin}, year={2025} }","mla":"Bot, Radu Ioan, and Konstantin Sonntag. “Inertial Dynamics with Vanishing Tikhonov Regularization for Multobjective Optimization.” Journal of Mathematical Analysis and Applications, 2025.","apa":"Bot, R. I., & Sonntag, K. (2025). Inertial dynamics with vanishing Tikhonov regularization for multobjective optimization. Journal of Mathematical Analysis and Applications.","ama":"Bot RI, Sonntag K. Inertial dynamics with vanishing Tikhonov regularization for multobjective optimization. Journal of Mathematical Analysis and Applications. Published online 2025.","ieee":"R. I. Bot and K. Sonntag, “Inertial dynamics with vanishing Tikhonov regularization for multobjective optimization,” Journal of Mathematical Analysis and Applications, 2025.","chicago":"Bot, Radu Ioan, and Konstantin Sonntag. “Inertial Dynamics with Vanishing Tikhonov Regularization for Multobjective Optimization.” Journal of Mathematical Analysis and Applications, 2025."},"_id":"57472","user_id":"56399","department":[{"_id":"101"},{"_id":"530"},{"_id":"655"}],"file_date_updated":"2024-11-28T08:58:00Z","type":"journal_article","status":"public","date_created":"2024-11-28T08:58:17Z","title":"Inertial dynamics with vanishing Tikhonov regularization for multobjective optimization","year":"2025","external_id":{"arxiv":["2411.18422"]},"ddc":["510"],"keyword":["Pareto optimization","Lyapunov analysis","gradient-like dynamical systems","inertial dynamics","asymptotic vanishing damping","Tikhonov regularization","strong convergence"],"language":[{"iso":"eng"}],"publication":"Journal of Mathematical Analysis and Applications","abstract":[{"text":"In this paper we introduce, in a Hilbert space setting, a second order dynamical system with asymptotically vanishing damping and vanishing Tikhonov regularization that approaches a multiobjective optimization problem with convex and differentiable components of the objective function. Trajectory solutions are shown to exist in finite dimensions. We prove fast convergence of the function values, quantified in terms of a merit function. Based on the regime considered, we establish both weak and, in some cases, strong convergence of trajectory solutions toward a weak Pareto optimal solution. To achieve this, we apply Tikhonov regularization individually to each component of the objective function. This work extends results from single objective convex optimization into the multiobjective setting.","lang":"eng"}],"file":[{"content_type":"application/pdf","relation":"main_file","date_updated":"2024-11-28T08:58:00Z","date_created":"2024-11-28T08:58:00Z","creator":"sonntagk","file_size":4291134,"file_id":"57473","access_level":"open_access","file_name":"Inertial dynamics with vanishing Tikhonov regularization for multobjective optimization.pdf"}],"license":"https://creativecommons.org/licenses/by-nc-sa/4.0/"},{"publication_status":"published","publication_identifier":{"isbn":["9781035325795","9781035325788","9781035325795"]},"quality_controlled":"1","year":"2025","citation":{"apa":"Fahrbach, M., Jenert, T., Fust, A., Bellwald, N., & Winkler, C. (2025). Fostering self-regulated entrepreneurial learning in entrepreneurship education. In Annals of Entrepreneurship Education and Pedagogy - 2025 (pp. 249–265). Edward Elgar Publishing. https://doi.org/10.4337/9781035325795.00021","mla":"Fahrbach, Manuel, et al. “Fostering Self-Regulated Entrepreneurial Learning in Entrepreneurship Education.” Annals of Entrepreneurship Education and Pedagogy - 2025, Edward Elgar Publishing, 2025, pp. 249–265, doi:10.4337/9781035325795.00021.","bibtex":"@inbook{Fahrbach_Jenert_Fust_Bellwald_Winkler_2025, title={Fostering self-regulated entrepreneurial learning in entrepreneurship education}, DOI={10.4337/9781035325795.00021}, booktitle={Annals of Entrepreneurship Education and Pedagogy - 2025}, publisher={Edward Elgar Publishing}, author={Fahrbach, Manuel and Jenert, Tobias and Fust, Alexander and Bellwald, Noah and Winkler, Christoph}, year={2025}, pages={249–265} }","short":"M. Fahrbach, T. Jenert, A. Fust, N. Bellwald, C. Winkler, in: Annals of Entrepreneurship Education and Pedagogy - 2025, Edward Elgar Publishing, 2025, pp. 249–265.","chicago":"Fahrbach, Manuel, Tobias Jenert, Alexander Fust, Noah Bellwald, and Christoph Winkler. “Fostering Self-Regulated Entrepreneurial Learning in Entrepreneurship Education.” In Annals of Entrepreneurship Education and Pedagogy - 2025, 249–265. Edward Elgar Publishing, 2025. https://doi.org/10.4337/9781035325795.00021.","ieee":"M. Fahrbach, T. Jenert, A. Fust, N. Bellwald, and C. Winkler, “Fostering self-regulated entrepreneurial learning in entrepreneurship education,” in Annals of Entrepreneurship Education and Pedagogy - 2025, Edward Elgar Publishing, 2025, pp. 249–265.","ama":"Fahrbach M, Jenert T, Fust A, Bellwald N, Winkler C. Fostering self-regulated entrepreneurial learning in entrepreneurship education. In: Annals of Entrepreneurship Education and Pedagogy - 2025. Edward Elgar Publishing; 2025:249–265. doi:10.4337/9781035325795.00021"},"page":"249–265","publisher":"Edward Elgar Publishing","date_updated":"2025-12-08T10:57:18Z","date_created":"2025-02-28T14:42:29Z","author":[{"first_name":"Manuel","full_name":"Fahrbach, Manuel","last_name":"Fahrbach"},{"first_name":"Tobias","id":"71994","full_name":"Jenert, Tobias","last_name":"Jenert","orcid":" https://orcid.org/0000-0001-9262-5646"},{"first_name":"Alexander","last_name":"Fust","full_name":"Fust, Alexander"},{"full_name":"Bellwald, Noah","last_name":"Bellwald","first_name":"Noah"},{"first_name":"Christoph","full_name":"Winkler, Christoph","last_name":"Winkler"}],"title":"Fostering self-regulated entrepreneurial learning in entrepreneurship education","doi":"10.4337/9781035325795.00021","type":"book_chapter","publication":"Annals of Entrepreneurship Education and Pedagogy - 2025","status":"public","project":[{"_id":"618","name":"Self-Regulated Learning for Entrepreneurs – Förderung der Selbstregulationsfähigkeit angehender Unternehmer*innen"}],"_id":"58874","user_id":"71994","department":[{"_id":"208"},{"_id":"640"}],"keyword":["Self-Regulated Learning","Entrepreneurship Education","Entrepreneurship Research"],"language":[{"iso":"eng"}]},{"title":"An Evolutionary Approach for the Computation of ∈-Locally Optimal Solutions for Multi-Objective Multimodal Optimization","doi":"10.1109/TEVC.2025.3637276","date_updated":"2025-12-12T06:13:51Z","author":[{"full_name":"Hernández, Carlos","last_name":"Hernández","first_name":"Carlos"},{"last_name":"Rodriguez-Fernandez","full_name":"Rodriguez-Fernandez, Angel E.","first_name":"Angel E."},{"full_name":"Schäpermeier, Lennart","last_name":"Schäpermeier","first_name":"Lennart"},{"first_name":"Oliver","last_name":"Cuate","full_name":"Cuate, Oliver"},{"first_name":"Heike","full_name":"Trautmann, Heike","id":"100740","last_name":"Trautmann","orcid":"0000-0002-9788-8282"},{"first_name":"Oliver","last_name":"Schütze","full_name":"Schütze, Oliver"}],"date_created":"2025-12-12T06:13:06Z","year":"2025","citation":{"bibtex":"@article{Hernández_Rodriguez-Fernandez_Schäpermeier_Cuate_Trautmann_Schütze_2025, title={An Evolutionary Approach for the Computation of ∈-Locally Optimal Solutions for Multi-Objective Multimodal Optimization}, DOI={10.1109/TEVC.2025.3637276}, journal={IEEE Transactions on Evolutionary Computation}, author={Hernández, Carlos and Rodriguez-Fernandez, Angel E. and Schäpermeier, Lennart and Cuate, Oliver and Trautmann, Heike and Schütze, Oliver}, year={2025}, pages={1–1} }","mla":"Hernández, Carlos, et al. “An Evolutionary Approach for the Computation of ∈-Locally Optimal Solutions for Multi-Objective Multimodal Optimization.” IEEE Transactions on Evolutionary Computation, 2025, pp. 1–1, doi:10.1109/TEVC.2025.3637276.","short":"C. Hernández, A.E. Rodriguez-Fernandez, L. Schäpermeier, O. Cuate, H. Trautmann, O. Schütze, IEEE Transactions on Evolutionary Computation (2025) 1–1.","apa":"Hernández, C., Rodriguez-Fernandez, A. E., Schäpermeier, L., Cuate, O., Trautmann, H., & Schütze, O. (2025). An Evolutionary Approach for the Computation of ∈-Locally Optimal Solutions for Multi-Objective Multimodal Optimization. IEEE Transactions on Evolutionary Computation, 1–1. https://doi.org/10.1109/TEVC.2025.3637276","ieee":"C. Hernández, A. E. Rodriguez-Fernandez, L. Schäpermeier, O. Cuate, H. Trautmann, and O. Schütze, “An Evolutionary Approach for the Computation of ∈-Locally Optimal Solutions for Multi-Objective Multimodal Optimization,” IEEE Transactions on Evolutionary Computation, pp. 1–1, 2025, doi: 10.1109/TEVC.2025.3637276.","chicago":"Hernández, Carlos, Angel E. Rodriguez-Fernandez, Lennart Schäpermeier, Oliver Cuate, Heike Trautmann, and Oliver Schütze. “An Evolutionary Approach for the Computation of ∈-Locally Optimal Solutions for Multi-Objective Multimodal Optimization.” IEEE Transactions on Evolutionary Computation, 2025, 1–1. https://doi.org/10.1109/TEVC.2025.3637276.","ama":"Hernández C, Rodriguez-Fernandez AE, Schäpermeier L, Cuate O, Trautmann H, Schütze O. An Evolutionary Approach for the Computation of ∈-Locally Optimal Solutions for Multi-Objective Multimodal Optimization. IEEE Transactions on Evolutionary Computation. Published online 2025:1-1. doi:10.1109/TEVC.2025.3637276"},"page":"1-1","keyword":["Optimization","Evolutionary computation","Hands","Proposals","Convergence","Computational efficiency","Artificial intelligence","Accuracy","Approximation algorithms","Aerospace electronics","Multi-objective optimization","evolutionary algorithms","nearly optimal solutions","multimodal optimization","archiving","continuation"],"language":[{"iso":"eng"}],"_id":"63053","user_id":"15504","department":[{"_id":"819"}],"status":"public","type":"journal_article","publication":"IEEE Transactions on Evolutionary Computation"},{"date_created":"2024-02-07T07:23:23Z","author":[{"full_name":"Gebken, Bennet","id":"32643","last_name":"Gebken","first_name":"Bennet"}],"publisher":"Springer Science and Business Media LLC","date_updated":"2024-02-08T08:05:54Z","doi":"10.1007/s10589-024-00552-0","title":"A note on the convergence of deterministic gradient sampling in nonsmooth optimization","publication_status":"published","publication_identifier":{"issn":["0926-6003","1573-2894"]},"citation":{"ama":"Gebken B. A note on the convergence of deterministic gradient sampling in nonsmooth optimization. Computational Optimization and Applications. Published online 2024. doi:10.1007/s10589-024-00552-0","chicago":"Gebken, Bennet. “A Note on the Convergence of Deterministic Gradient Sampling in Nonsmooth Optimization.” Computational Optimization and Applications, 2024. https://doi.org/10.1007/s10589-024-00552-0.","ieee":"B. Gebken, “A note on the convergence of deterministic gradient sampling in nonsmooth optimization,” Computational Optimization and Applications, 2024, doi: 10.1007/s10589-024-00552-0.","short":"B. Gebken, Computational Optimization and Applications (2024).","mla":"Gebken, Bennet. “A Note on the Convergence of Deterministic Gradient Sampling in Nonsmooth Optimization.” Computational Optimization and Applications, Springer Science and Business Media LLC, 2024, doi:10.1007/s10589-024-00552-0.","bibtex":"@article{Gebken_2024, title={A note on the convergence of deterministic gradient sampling in nonsmooth optimization}, DOI={10.1007/s10589-024-00552-0}, journal={Computational Optimization and Applications}, publisher={Springer Science and Business Media LLC}, author={Gebken, Bennet}, year={2024} }","apa":"Gebken, B. (2024). A note on the convergence of deterministic gradient sampling in nonsmooth optimization. Computational Optimization and Applications. https://doi.org/10.1007/s10589-024-00552-0"},"year":"2024","user_id":"32643","department":[{"_id":"101"}],"_id":"51208","language":[{"iso":"eng"}],"keyword":["Applied Mathematics","Computational Mathematics","Control and Optimization"],"type":"journal_article","publication":"Computational Optimization and Applications","status":"public","abstract":[{"lang":"eng","text":"AbstractApproximation of subdifferentials is one of the main tasks when computing descent directions for nonsmooth optimization problems. In this article, we propose a bisection method for weakly lower semismooth functions which is able to compute new subgradients that improve a given approximation in case a direction with insufficient descent was computed. Combined with a recently proposed deterministic gradient sampling approach, this yields a deterministic and provably convergent way to approximate subdifferentials for computing descent directions."}]},{"issue":"3","quality_controlled":"1","year":"2024","date_created":"2024-02-20T06:46:43Z","publisher":"MDPI AG","title":"Diagnostics of Piezoelectric Bending Actuators Subjected to Varying Operating Conditions","publication":"Electronics","abstract":[{"text":"In applications of piezoelectric actuators and sensors, the dependability and particularly the reliability throughout their lifetime are vital to manufacturers and end-users and are enabled through condition-monitoring approaches. Existing approaches often utilize impedance measurements over a range of frequencies or velocity measurements and require additional equipment or sensors, such as a laser Doppler vibrometer. Furthermore, the non-negligible effects of varying operating conditions are often unconsidered. To minimize the need for additional sensors while maintaining the dependability of piezoelectric bending actuators irrespective of varying operating conditions, an online diagnostics approach is proposed. To this end, time- and frequency-domain features are extracted from monitored current signals to reflect hairline crack development in bending actuators. For validation of applicability, the presented analysis method was evaluated on piezoelectric bending actuators subjected to accelerated lifetime tests at varying voltage amplitudes and under external damping conditions. In the presence of a crack and due to a diminished stiffness, the resonance frequency decreases and the root-mean-square amplitude of the current signal simultaneously abruptly drops during the lifetime tests. Furthermore, the piezoelectric crack surfaces clapping is reflected in higher harmonics of the current signal. Thus, time-domain features and harmonics of the current signals are sufficient to diagnose hairline cracks in the actuators.","lang":"eng"}],"language":[{"iso":"eng"}],"keyword":["piezoelectric transducer","self-sensing","fault detection","diagnostics","hairline crack","condition monitoring"],"publication_identifier":{"issn":["2079-9292"]},"publication_status":"published","intvolume":" 13","citation":{"short":"O.K. Aimiyekagbon, A. Bender, T. Hemsel, W. Sextro, Electronics 13 (2024).","bibtex":"@article{Aimiyekagbon_Bender_Hemsel_Sextro_2024, title={Diagnostics of Piezoelectric Bending Actuators Subjected to Varying Operating Conditions}, volume={13}, DOI={10.3390/electronics13030521}, number={3521}, journal={Electronics}, publisher={MDPI AG}, author={Aimiyekagbon, Osarenren Kennedy and Bender, Amelie and Hemsel, Tobias and Sextro, Walter}, year={2024} }","mla":"Aimiyekagbon, Osarenren Kennedy, et al. “Diagnostics of Piezoelectric Bending Actuators Subjected to Varying Operating Conditions.” Electronics, vol. 13, no. 3, 521, MDPI AG, 2024, doi:10.3390/electronics13030521.","apa":"Aimiyekagbon, O. K., Bender, A., Hemsel, T., & Sextro, W. (2024). Diagnostics of Piezoelectric Bending Actuators Subjected to Varying Operating Conditions. Electronics, 13(3), Article 521. https://doi.org/10.3390/electronics13030521","ama":"Aimiyekagbon OK, Bender A, Hemsel T, Sextro W. Diagnostics of Piezoelectric Bending Actuators Subjected to Varying Operating Conditions. Electronics. 2024;13(3). doi:10.3390/electronics13030521","chicago":"Aimiyekagbon, Osarenren Kennedy, Amelie Bender, Tobias Hemsel, and Walter Sextro. “Diagnostics of Piezoelectric Bending Actuators Subjected to Varying Operating Conditions.” Electronics 13, no. 3 (2024). https://doi.org/10.3390/electronics13030521.","ieee":"O. K. Aimiyekagbon, A. Bender, T. Hemsel, and W. Sextro, “Diagnostics of Piezoelectric Bending Actuators Subjected to Varying Operating Conditions,” Electronics, vol. 13, no. 3, Art. no. 521, 2024, doi: 10.3390/electronics13030521."},"volume":13,"author":[{"id":"9557","full_name":"Aimiyekagbon, Osarenren Kennedy","last_name":"Aimiyekagbon","first_name":"Osarenren Kennedy"},{"first_name":"Amelie","id":"54290","full_name":"Bender, Amelie","last_name":"Bender"},{"id":"210","full_name":"Hemsel, Tobias","last_name":"Hemsel","first_name":"Tobias"},{"last_name":"Sextro","id":"21220","full_name":"Sextro, Walter","first_name":"Walter"}],"date_updated":"2024-03-15T16:15:56Z","doi":"10.3390/electronics13030521","type":"journal_article","status":"public","department":[{"_id":"151"}],"user_id":"9557","_id":"51518","funded_apc":"1","article_number":"521","article_type":"original"},{"type":"journal_article","status":"public","_id":"52726","department":[{"_id":"101"}],"user_id":"97359","article_type":"original","file_date_updated":"2024-03-22T09:06:07Z","has_accepted_license":"1","publication_identifier":{"issn":["2051-1329"]},"publication_status":"published","intvolume":" 12","citation":{"apa":"Bick, C., & von der Gracht, S. (2024). Heteroclinic dynamics in network dynamical systems with higher-order interactions. Journal of Complex Networks, 12(2). https://doi.org/10.1093/comnet/cnae009","short":"C. Bick, S. von der Gracht, Journal of Complex Networks 12 (2024).","bibtex":"@article{Bick_von der Gracht_2024, title={Heteroclinic dynamics in network dynamical systems with higher-order interactions}, volume={12}, DOI={10.1093/comnet/cnae009}, number={2}, journal={Journal of Complex Networks}, publisher={Oxford University Press (OUP)}, author={Bick, Christian and von der Gracht, Sören}, year={2024} }","mla":"Bick, Christian, and Sören von der Gracht. “Heteroclinic Dynamics in Network Dynamical Systems with Higher-Order Interactions.” Journal of Complex Networks, vol. 12, no. 2, Oxford University Press (OUP), 2024, doi:10.1093/comnet/cnae009.","ama":"Bick C, von der Gracht S. Heteroclinic dynamics in network dynamical systems with higher-order interactions. Journal of Complex Networks. 2024;12(2). doi:10.1093/comnet/cnae009","ieee":"C. Bick and S. von der Gracht, “Heteroclinic dynamics in network dynamical systems with higher-order interactions,” Journal of Complex Networks, vol. 12, no. 2, 2024, doi: 10.1093/comnet/cnae009.","chicago":"Bick, Christian, and Sören von der Gracht. “Heteroclinic Dynamics in Network Dynamical Systems with Higher-Order Interactions.” Journal of Complex Networks 12, no. 2 (2024). https://doi.org/10.1093/comnet/cnae009."},"oa":"1","date_updated":"2024-03-22T09:11:53Z","volume":12,"author":[{"first_name":"Christian","full_name":"Bick, Christian","last_name":"Bick"},{"full_name":"von der Gracht, Sören","id":"97359","orcid":"0000-0002-8054-2058","last_name":"von der Gracht","first_name":"Sören"}],"doi":"10.1093/comnet/cnae009","main_file_link":[{"url":"https://academic.oup.com/comnet/article-pdf/12/2/cnae009/56832119/cnae009.pdf","open_access":"1"}],"publication":"Journal of Complex Networks","abstract":[{"lang":"eng","text":"Heteroclinic structures organize global features of dynamical systems. We analyse whether heteroclinic structures can arise in network dynamics with higher-order interactions which describe the nonlinear interactions between three or more units. We find that while commonly analysed model equations such as network dynamics on undirected hypergraphs may be useful to describe local dynamics such as cluster synchronization, they give rise to obstructions that allow to design of heteroclinic structures in phase space. By contrast, directed hypergraphs break the homogeneity and lead to vector fields that support heteroclinic structures."}],"license":"https://creativecommons.org/licenses/by-nc/4.0/","file":[{"content_type":"application/pdf","success":1,"relation":"main_file","date_updated":"2024-03-22T09:06:07Z","creator":"svdg","date_created":"2024-03-22T09:06:07Z","file_size":649155,"file_name":"heteroclinic-dynamics-in-network-dynamical-systems-with-higher-order-interactions.pdf","access_level":"closed","file_id":"52728"}],"external_id":{"arxiv":["2309.02006"]},"keyword":["Applied Mathematics","Computational Mathematics","Control and Optimization","Management Science and Operations Research","Computer Networks and Communications"],"ddc":["510"],"language":[{"iso":"eng"}],"issue":"2","year":"2024","publisher":"Oxford University Press (OUP)","date_created":"2024-03-22T09:04:57Z","title":"Heteroclinic dynamics in network dynamical systems with higher-order interactions"},{"year":"2024","citation":{"ama":"Prager RP, Trautmann H. Exploratory Landscape Analysis for Mixed-Variable Problems. IEEE Transactions on Evolutionary Computation. Published online 2024:1-1. doi:10.1109/TEVC.2024.3399560","chicago":"Prager, Raphael Patrick, and Heike Trautmann. “Exploratory Landscape Analysis for Mixed-Variable Problems.” IEEE Transactions on Evolutionary Computation, 2024, 1–1. https://doi.org/10.1109/TEVC.2024.3399560.","ieee":"R. P. Prager and H. Trautmann, “Exploratory Landscape Analysis for Mixed-Variable Problems,” IEEE Transactions on Evolutionary Computation, pp. 1–1, 2024, doi: 10.1109/TEVC.2024.3399560.","apa":"Prager, R. P., & Trautmann, H. (2024). Exploratory Landscape Analysis for Mixed-Variable Problems. IEEE Transactions on Evolutionary Computation, 1–1. https://doi.org/10.1109/TEVC.2024.3399560","bibtex":"@article{Prager_Trautmann_2024, title={Exploratory Landscape Analysis for Mixed-Variable Problems}, DOI={10.1109/TEVC.2024.3399560}, journal={IEEE Transactions on Evolutionary Computation}, author={Prager, Raphael Patrick and Trautmann, Heike}, year={2024}, pages={1–1} }","mla":"Prager, Raphael Patrick, and Heike Trautmann. “Exploratory Landscape Analysis for Mixed-Variable Problems.” IEEE Transactions on Evolutionary Computation, 2024, pp. 1–1, doi:10.1109/TEVC.2024.3399560.","short":"R.P. Prager, H. Trautmann, IEEE Transactions on Evolutionary Computation (2024) 1–1."},"page":"1-1","title":"Exploratory Landscape Analysis for Mixed-Variable Problems","doi":"10.1109/TEVC.2024.3399560","date_updated":"2024-06-03T06:17:13Z","date_created":"2024-06-03T06:16:33Z","author":[{"first_name":"Raphael Patrick","full_name":"Prager, Raphael Patrick","last_name":"Prager"},{"last_name":"Trautmann","orcid":"0000-0002-9788-8282","id":"100740","full_name":"Trautmann, Heike","first_name":"Heike"}],"status":"public","type":"journal_article","publication":"IEEE Transactions on Evolutionary Computation","keyword":["Optimization","Evolutionary computation","Benchmark testing","Hyperparameter optimization","Portfolios","Extraterrestrial measurements","Dispersion","Exploratory landscape analysis","mixed-variable problem","mixed search spaces","automated algorithm selection"],"language":[{"iso":"eng"}],"_id":"54548","user_id":"15504","department":[{"_id":"819"}]},{"issue":"3","publication_status":"published","publication_identifier":{"issn":["1095-7189"]},"citation":{"chicago":"Sonntag, Konstantin, and Sebastian Peitz. “Fast Convergence of Inertial Multiobjective Gradient-Like Systems with Asymptotic Vanishing Damping.” SIAM Journal on Optimization 34, no. 3 (2024): 2259–86. https://doi.org/10.1137/23M1588512.","ieee":"K. Sonntag and S. Peitz, “Fast Convergence of Inertial Multiobjective Gradient-Like Systems with Asymptotic Vanishing Damping,” SIAM Journal on Optimization, vol. 34, no. 3, pp. 2259–2286, 2024, doi: 10.1137/23M1588512.","short":"K. Sonntag, S. Peitz, SIAM Journal on Optimization 34 (2024) 2259–2286.","mla":"Sonntag, Konstantin, and Sebastian Peitz. “Fast Convergence of Inertial Multiobjective Gradient-Like Systems with Asymptotic Vanishing Damping.” SIAM Journal on Optimization, vol. 34, no. 3, Society for Industrial and Applied Mathematics, 2024, pp. 2259–86, doi:10.1137/23M1588512.","bibtex":"@article{Sonntag_Peitz_2024, title={Fast Convergence of Inertial Multiobjective Gradient-Like Systems with Asymptotic Vanishing Damping}, volume={34}, DOI={10.1137/23M1588512}, number={3}, journal={SIAM Journal on Optimization}, publisher={Society for Industrial and Applied Mathematics}, author={Sonntag, Konstantin and Peitz, Sebastian}, year={2024}, pages={2259–2286} }","ama":"Sonntag K, Peitz S. Fast Convergence of Inertial Multiobjective Gradient-Like Systems with Asymptotic Vanishing Damping. SIAM Journal on Optimization. 2024;34(3):2259-2286. doi:10.1137/23M1588512","apa":"Sonntag, K., & Peitz, S. (2024). Fast Convergence of Inertial Multiobjective Gradient-Like Systems with Asymptotic Vanishing Damping. SIAM Journal on Optimization, 34(3), 2259–2286. https://doi.org/10.1137/23M1588512"},"page":"2259 - 2286","intvolume":" 34","year":"2024","author":[{"first_name":"Konstantin","full_name":"Sonntag, Konstantin","id":"56399","last_name":"Sonntag","orcid":"https://orcid.org/0000-0003-3384-3496"},{"orcid":"0000-0002-3389-793X","last_name":"Peitz","full_name":"Peitz, Sebastian","id":"47427","first_name":"Sebastian"}],"date_created":"2022-07-28T11:53:02Z","volume":34,"publisher":"Society for Industrial and Applied Mathematics","date_updated":"2024-07-02T09:27:39Z","doi":"10.1137/23M1588512","title":"Fast Convergence of Inertial Multiobjective Gradient-Like Systems with Asymptotic Vanishing Damping","type":"journal_article","publication":"SIAM Journal on Optimization","status":"public","abstract":[{"lang":"eng","text":"We present a new gradient-like dynamical system related to unconstrained convex smooth multiobjective optimization which involves inertial effects and asymptotic vanishing damping. To the best of our knowledge, this system is the first inertial gradient-like system for multiobjective optimization problems including asymptotic vanishing damping, expanding the ideas previously laid out in [H. Attouch and G. Garrigos, Multiobjective Optimization: An Inertial Dynamical Approach to Pareto Optima, preprint, arXiv:1506.02823, 2015]. We prove existence of solutions to this system in finite dimensions and further prove that its bounded solutions converge weakly to weakly Pareto optimal points. In addition, we obtain a convergence rate of order \\(\\mathcal{O}(t^{-2})\\) for the function values measured with a merit function. This approach presents a good basis for the development of fast gradient methods for multiobjective optimization."}],"user_id":"56399","department":[{"_id":"101"},{"_id":"655"}],"_id":"32447","language":[{"iso":"eng"}],"article_type":"original","keyword":["multiobjective optimization","Pareto optimization","Lyapunov analysis","gradient-likedynamical systems","inertial dynamics","asymptotic vanishing damping","fast convergence"]},{"citation":{"ama":"Rodriguez-Fernandez AE, Schäpermeier L, Hernández C, Kerschke P, Trautmann H, Schütze O. Finding ϵ-Locally Optimal Solutions for Multi-Objective Multimodal Optimization. IEEE Transactions on Evolutionary Computation. Published online 2024:1-1. doi:10.1109/TEVC.2024.3458855","ieee":"A. E. Rodriguez-Fernandez, L. Schäpermeier, C. Hernández, P. Kerschke, H. Trautmann, and O. Schütze, “Finding ϵ-Locally Optimal Solutions for Multi-Objective Multimodal Optimization,” IEEE Transactions on Evolutionary Computation, pp. 1–1, 2024, doi: 10.1109/TEVC.2024.3458855.","chicago":"Rodriguez-Fernandez, Angel E., Lennart Schäpermeier, Carlos Hernández, Pascal Kerschke, Heike Trautmann, and Oliver Schütze. “Finding ϵ-Locally Optimal Solutions for Multi-Objective Multimodal Optimization.” IEEE Transactions on Evolutionary Computation, 2024, 1–1. https://doi.org/10.1109/TEVC.2024.3458855.","short":"A.E. Rodriguez-Fernandez, L. Schäpermeier, C. Hernández, P. Kerschke, H. Trautmann, O. Schütze, IEEE Transactions on Evolutionary Computation (2024) 1–1.","mla":"Rodriguez-Fernandez, Angel E., et al. “Finding ϵ-Locally Optimal Solutions for Multi-Objective Multimodal Optimization.” IEEE Transactions on Evolutionary Computation, 2024, pp. 1–1, doi:10.1109/TEVC.2024.3458855.","bibtex":"@article{Rodriguez-Fernandez_Schäpermeier_Hernández_Kerschke_Trautmann_Schütze_2024, title={Finding ϵ-Locally Optimal Solutions for Multi-Objective Multimodal Optimization}, DOI={10.1109/TEVC.2024.3458855}, journal={IEEE Transactions on Evolutionary Computation}, author={Rodriguez-Fernandez, Angel E. and Schäpermeier, Lennart and Hernández, Carlos and Kerschke, Pascal and Trautmann, Heike and Schütze, Oliver}, year={2024}, pages={1–1} }","apa":"Rodriguez-Fernandez, A. E., Schäpermeier, L., Hernández, C., Kerschke, P., Trautmann, H., & Schütze, O. (2024). Finding ϵ-Locally Optimal Solutions for Multi-Objective Multimodal Optimization. IEEE Transactions on Evolutionary Computation, 1–1. https://doi.org/10.1109/TEVC.2024.3458855"},"page":"1-1","year":"2024","date_created":"2024-09-24T08:01:14Z","author":[{"full_name":"Rodriguez-Fernandez, Angel E.","last_name":"Rodriguez-Fernandez","first_name":"Angel E."},{"first_name":"Lennart","full_name":"Schäpermeier, Lennart","last_name":"Schäpermeier"},{"first_name":"Carlos","last_name":"Hernández","full_name":"Hernández, Carlos"},{"first_name":"Pascal","full_name":"Kerschke, Pascal","last_name":"Kerschke"},{"first_name":"Heike","id":"100740","full_name":"Trautmann, Heike","orcid":"0000-0002-9788-8282","last_name":"Trautmann"},{"last_name":"Schütze","full_name":"Schütze, Oliver","first_name":"Oliver"}],"date_updated":"2024-09-24T08:01:47Z","doi":"10.1109/TEVC.2024.3458855","title":"Finding ϵ-Locally Optimal Solutions for Multi-Objective Multimodal Optimization","type":"journal_article","publication":"IEEE Transactions on Evolutionary Computation","status":"public","user_id":"15504","_id":"56221","language":[{"iso":"eng"}],"keyword":["Optimization","Evolutionary computation","Approximation algorithms","Benchmark testing","Vectors","Surveys","Pareto optimization","multi-objective optimization","evolutionary computation","multimodal optimization","local solutions"]},{"author":[{"full_name":"Förster, Nikolas","last_name":"Förster","first_name":"Nikolas"},{"last_name":"Wallscheid","full_name":"Wallscheid, Oliver","first_name":"Oliver"},{"first_name":"Frank","last_name":"Schafmeister","full_name":"Schafmeister, Frank"}],"date_created":"2026-01-06T08:06:24Z","date_updated":"2026-01-06T08:07:50Z","doi":"10.1109/DMC62632.2024.10812131","title":"Dual-Active Bridge Sequential Pareto Optimization for Fast Pre-Design and Final Component Selection","page":"1-8","citation":{"short":"N. Förster, O. Wallscheid, F. Schafmeister, in: 2024 IEEE Design Methodologies Conference (DMC), 2024, pp. 1–8.","bibtex":"@inproceedings{Förster_Wallscheid_Schafmeister_2024, title={Dual-Active Bridge Sequential Pareto Optimization for Fast Pre-Design and Final Component Selection}, DOI={10.1109/DMC62632.2024.10812131}, booktitle={2024 IEEE Design Methodologies Conference (DMC)}, author={Förster, Nikolas and Wallscheid, Oliver and Schafmeister, Frank}, year={2024}, pages={1–8} }","mla":"Förster, Nikolas, et al. “Dual-Active Bridge Sequential Pareto Optimization for Fast Pre-Design and Final Component Selection.” 2024 IEEE Design Methodologies Conference (DMC), 2024, pp. 1–8, doi:10.1109/DMC62632.2024.10812131.","apa":"Förster, N., Wallscheid, O., & Schafmeister, F. (2024). Dual-Active Bridge Sequential Pareto Optimization for Fast Pre-Design and Final Component Selection. 2024 IEEE Design Methodologies Conference (DMC), 1–8. https://doi.org/10.1109/DMC62632.2024.10812131","chicago":"Förster, Nikolas, Oliver Wallscheid, and Frank Schafmeister. “Dual-Active Bridge Sequential Pareto Optimization for Fast Pre-Design and Final Component Selection.” In 2024 IEEE Design Methodologies Conference (DMC), 1–8, 2024. https://doi.org/10.1109/DMC62632.2024.10812131.","ieee":"N. Förster, O. Wallscheid, and F. Schafmeister, “Dual-Active Bridge Sequential Pareto Optimization for Fast Pre-Design and Final Component Selection,” in 2024 IEEE Design Methodologies Conference (DMC), 2024, pp. 1–8, doi: 10.1109/DMC62632.2024.10812131.","ama":"Förster N, Wallscheid O, Schafmeister F. Dual-Active Bridge Sequential Pareto Optimization for Fast Pre-Design and Final Component Selection. In: 2024 IEEE Design Methodologies Conference (DMC). ; 2024:1-8. doi:10.1109/DMC62632.2024.10812131"},"year":"2024","department":[{"_id":"52"}],"user_id":"83383","_id":"63497","language":[{"iso":"eng"}],"keyword":["MOSFET","Thermal resistance","Surface resistance","Bridge circuits","Zero voltage switching","Pareto optimization","Capacitance","Numerical simulation","Optimization","Resistance heating","Pareto Optimization","Dual-Active Bridge","ZVS","Inductor Optimization","Transformer Optimization","Heat Sink Optimization"],"publication":"2024 IEEE Design Methodologies Conference (DMC)","type":"conference","status":"public"},{"author":[{"first_name":"Deviprasad","full_name":"Chalicheemalapalli Jayasankar, Deviprasad","id":"49504","orcid":"https://orcid.org/ 0000-0002-3446-2444","last_name":"Chalicheemalapalli Jayasankar"},{"full_name":"Gnaase, Stefan","id":"25730","last_name":"Gnaase","first_name":"Stefan"},{"first_name":"Maximilian Alexander","last_name":"Kaiser","orcid":"0009-0008-1333-3396","id":"72351","full_name":"Kaiser, Maximilian Alexander"},{"first_name":"Dennis","full_name":"Lehnert, Dennis","id":"90491","last_name":"Lehnert"},{"first_name":"Thomas","full_name":"Tröster, Thomas","id":"553","last_name":"Tröster"}],"volume":14,"oa":"1","date_updated":"2026-03-20T08:44:23Z","main_file_link":[{"open_access":"1","url":"https://www.mdpi.com/2075-4701/14/7/772"}],"doi":"10.3390/met14070772","publication_status":"published","publication_identifier":{"issn":["2075-4701"]},"citation":{"mla":"Chalicheemalapalli Jayasankar, Deviprasad, et al. “Advancements in Hybrid Additive Manufacturing: Integrating SLM and LMD for High-Performance Applications.” Metals, vol. 14, no. 7, 772, MDPI AG, 2024, doi:10.3390/met14070772.","bibtex":"@article{Chalicheemalapalli Jayasankar_Gnaase_Kaiser_Lehnert_Tröster_2024, title={Advancements in Hybrid Additive Manufacturing: Integrating SLM and LMD for High-Performance Applications}, volume={14}, DOI={10.3390/met14070772}, number={7772}, journal={Metals}, publisher={MDPI AG}, author={Chalicheemalapalli Jayasankar, Deviprasad and Gnaase, Stefan and Kaiser, Maximilian Alexander and Lehnert, Dennis and Tröster, Thomas}, year={2024} }","short":"D. Chalicheemalapalli Jayasankar, S. Gnaase, M.A. Kaiser, D. Lehnert, T. Tröster, Metals 14 (2024).","apa":"Chalicheemalapalli Jayasankar, D., Gnaase, S., Kaiser, M. A., Lehnert, D., & Tröster, T. (2024). Advancements in Hybrid Additive Manufacturing: Integrating SLM and LMD for High-Performance Applications. Metals, 14(7), Article 772. https://doi.org/10.3390/met14070772","ama":"Chalicheemalapalli Jayasankar D, Gnaase S, Kaiser MA, Lehnert D, Tröster T. Advancements in Hybrid Additive Manufacturing: Integrating SLM and LMD for High-Performance Applications. Metals. 2024;14(7). doi:10.3390/met14070772","ieee":"D. Chalicheemalapalli Jayasankar, S. Gnaase, M. A. Kaiser, D. Lehnert, and T. Tröster, “Advancements in Hybrid Additive Manufacturing: Integrating SLM and LMD for High-Performance Applications,” Metals, vol. 14, no. 7, Art. no. 772, 2024, doi: 10.3390/met14070772.","chicago":"Chalicheemalapalli Jayasankar, Deviprasad, Stefan Gnaase, Maximilian Alexander Kaiser, Dennis Lehnert, and Thomas Tröster. “Advancements in Hybrid Additive Manufacturing: Integrating SLM and LMD for High-Performance Applications.” Metals 14, no. 7 (2024). https://doi.org/10.3390/met14070772."},"intvolume":" 14","user_id":"49504","department":[{"_id":"9"},{"_id":"321"},{"_id":"149"}],"_id":"56089","article_number":"772","article_type":"original","type":"journal_article","status":"public","date_created":"2024-09-10T10:19:32Z","publisher":"MDPI AG","title":"Advancements in Hybrid Additive Manufacturing: Integrating SLM and LMD for High-Performance Applications","issue":"7","quality_controlled":"1","year":"2024","language":[{"iso":"eng"}],"keyword":["additive manufacturing (AM)","selective laser melting (SLM)","laser metal deposition (LMD)","hybrid manufacturing","process optimization","316L","1.2709"],"publication":"Metals","abstract":[{"lang":"eng","text":"Additive manufacturing (AM) technologies enable near-net-shape designs and demand-oriented material usage, which significantly minimizes waste. This points to a substantial opportunity for further optimization in material savings and process design. The current study delves into the advancement of sustainable manufacturing practices in the automotive industry, emphasizing the crucial role of lightweight construction concepts and AM technologies in enhancing resource efficiency and reducing greenhouse gas emissions. By exploring the integration of novel AM techniques such as selective laser melting (SLM) and laser metal deposition (LMD), the study aims to overcome existing limitations like slow build-up rates and limited component resolution. The study’s core objective revolves around the development and validation of a continuous process chain that synergizes different AM routes. In the current study, the continuous process chain for DMG MORI Lasertec 65 3D’s LMD system and the DMG MORI Lasertec 30 3D’s was demonstrated using 316L and 1.2709 steel materials. This integrated approach is designed to significantly curtail process times and minimize component costs, thus suggesting an industry-oriented process chain for future manufacturing paradigms. Additionally, the research investigates the production and material behavior of components under varying manufacturing processes, material combinations, and boundary layer materials. The culmination of this study is the validation of the proposed process route through a technology demonstrator, assessing its scalability and setting a benchmark for resource-efficient manufacturing in the automotive sector."}]},{"publication_identifier":{"isbn":["9798400702020"]},"page":"129–139","citation":{"short":"R.P. Prager, K. Dietrich, L. Schneider, L. Schäpermeier, B. Bischl, P. Kerschke, H. Trautmann, O. Mersmann, in: Proceedings of the 17th ACM/SIGEVO Conference on Foundations of Genetic Algorithms, Association for Computing Machinery, New York, NY, USA, 2023, pp. 129–139.","mla":"Prager, Raphael Patrick, et al. “Neural Networks as Black-Box Benchmark Functions Optimized for Exploratory Landscape Features.” Proceedings of the 17th ACM/SIGEVO Conference on Foundations of Genetic Algorithms, Association for Computing Machinery, 2023, pp. 129–139, doi:10.1145/3594805.3607136.","bibtex":"@inproceedings{Prager_Dietrich_Schneider_Schäpermeier_Bischl_Kerschke_Trautmann_Mersmann_2023, place={New York, NY, USA}, series={FOGA ’23}, title={Neural Networks as Black-Box Benchmark Functions Optimized for Exploratory Landscape Features}, DOI={10.1145/3594805.3607136}, booktitle={Proceedings of the 17th ACM/SIGEVO Conference on Foundations of Genetic Algorithms}, publisher={Association for Computing Machinery}, author={Prager, Raphael Patrick and Dietrich, Konstantin and Schneider, Lennart and Schäpermeier, Lennart and Bischl, Bernd and Kerschke, Pascal and Trautmann, Heike and Mersmann, Olaf}, year={2023}, pages={129–139}, collection={FOGA ’23} }","apa":"Prager, R. P., Dietrich, K., Schneider, L., Schäpermeier, L., Bischl, B., Kerschke, P., Trautmann, H., & Mersmann, O. (2023). Neural Networks as Black-Box Benchmark Functions Optimized for Exploratory Landscape Features. Proceedings of the 17th ACM/SIGEVO Conference on Foundations of Genetic Algorithms, 129–139. https://doi.org/10.1145/3594805.3607136","chicago":"Prager, Raphael Patrick, Konstantin Dietrich, Lennart Schneider, Lennart Schäpermeier, Bernd Bischl, Pascal Kerschke, Heike Trautmann, and Olaf Mersmann. “Neural Networks as Black-Box Benchmark Functions Optimized for Exploratory Landscape Features.” In Proceedings of the 17th ACM/SIGEVO Conference on Foundations of Genetic Algorithms, 129–139. FOGA ’23. New York, NY, USA: Association for Computing Machinery, 2023. https://doi.org/10.1145/3594805.3607136.","ieee":"R. P. Prager et al., “Neural Networks as Black-Box Benchmark Functions Optimized for Exploratory Landscape Features,” in Proceedings of the 17th ACM/SIGEVO Conference on Foundations of Genetic Algorithms, 2023, pp. 129–139, doi: 10.1145/3594805.3607136.","ama":"Prager RP, Dietrich K, Schneider L, et al. Neural Networks as Black-Box Benchmark Functions Optimized for Exploratory Landscape Features. In: Proceedings of the 17th ACM/SIGEVO Conference on Foundations of Genetic Algorithms. FOGA ’23. Association for Computing Machinery; 2023:129–139. doi:10.1145/3594805.3607136"},"year":"2023","place":"New York, NY, USA","author":[{"last_name":"Prager","full_name":"Prager, Raphael Patrick","first_name":"Raphael Patrick"},{"first_name":"Konstantin","full_name":"Dietrich, Konstantin","last_name":"Dietrich"},{"first_name":"Lennart","full_name":"Schneider, Lennart","last_name":"Schneider"},{"last_name":"Schäpermeier","full_name":"Schäpermeier, Lennart","first_name":"Lennart"},{"full_name":"Bischl, Bernd","last_name":"Bischl","first_name":"Bernd"},{"first_name":"Pascal","full_name":"Kerschke, Pascal","last_name":"Kerschke"},{"id":"100740","full_name":"Trautmann, Heike","last_name":"Trautmann","orcid":"0000-0002-9788-8282","first_name":"Heike"},{"full_name":"Mersmann, Olaf","last_name":"Mersmann","first_name":"Olaf"}],"date_created":"2023-09-27T15:43:17Z","publisher":"Association for Computing Machinery","date_updated":"2023-10-16T12:33:02Z","doi":"10.1145/3594805.3607136","title":"Neural Networks as Black-Box Benchmark Functions Optimized for Exploratory Landscape Features","publication":"Proceedings of the 17th ACM/SIGEVO Conference on Foundations of Genetic Algorithms","type":"conference","status":"public","abstract":[{"text":"Artificial benchmark functions are commonly used in optimization research because of their ability to rapidly evaluate potential solutions, making them a preferred substitute for real-world problems. However, these benchmark functions have faced criticism for their limited resemblance to real-world problems. In response, recent research has focused on automatically generating new benchmark functions for areas where established test suites are inadequate. These approaches have limitations, such as the difficulty of generating new benchmark functions that exhibit exploratory landscape analysis (ELA) features beyond those of existing benchmarks.The objective of this work is to develop a method for generating benchmark functions for single-objective continuous optimization with user-specified structural properties. Specifically, we aim to demonstrate a proof of concept for a method that uses an ELA feature vector to specify these properties in advance. To achieve this, we begin by generating a random sample of decision space variables and objective values. We then adjust the objective values using CMA-ES until the corresponding features of our new problem match the predefined ELA features within a specified threshold. By iteratively transforming the landscape in this way, we ensure that the resulting function exhibits the desired properties. To create the final function, we use the resulting point cloud as training data for a simple neural network that produces a function exhibiting the target ELA features. We demonstrate the effectiveness of this approach by replicating the existing functions of the well-known BBOB suite and creating new functions with ELA feature values that are not present in BBOB.","lang":"eng"}],"department":[{"_id":"34"},{"_id":"819"}],"user_id":"15504","series_title":"FOGA ’23","_id":"47522","language":[{"iso":"eng"}],"keyword":["Benchmarking","Instance Generator","Black-Box Continuous Optimization","Exploratory Landscape Analysis","Neural Networks"]}]