@article{63512, abstract = {{The state of the art shows that PBF-LB/M offers great potential for pressure-loaded parts, with significant weight reductions and simultaneous optimization of flow resistance. This study is aimed at applying existing calculation methods for pressure-loaded parts to additively manufactured pipe structures, considering the two materials EN AC-43000 (3.2381, AlSi10Mg) and AISI 316L (1.4404, X2CrNiMo17-12-2). For this purpose, systematic tensile tests are carried out for both materials. In addition, a statistical evaluation is performed to determine the design-relevant strength characteristics with a survival probability Ps of 97.5 % for both materials in the as-built and heat-treated condition. Pipe specimens are manufactured, half of which are heat treated, geometrically measured and then subjected to a burst pressure test to experimentally determine the failure-critical internal pressure. These results are compared with calculated burst pressures. The calculations are based on the application-relevant methods identified in this study, considering the strength values determined for the respective material condition. This comparison is used to assess the suitability of the calculation methods for additively manufactured pipe structures, based on the materials investigated.}}, author = {{Koers, Thorsten and Magyar, Balázs and Bödger, Christian and Tröster, Thomas}}, issn = {{0308-0161}}, journal = {{International Journal of Pressure Vessels and Piping}}, keywords = {{PBF-LB/M, Pipe structures, Strength assessment, Burst pressure test, Geometrical deviations}}, publisher = {{Elsevier BV}}, title = {{{Analytical and experimental determination of the failure-critical pressure of pipe structures manufactured by PBF-LB/M}}}, doi = {{10.1016/j.ijpvp.2026.105753}}, year = {{2026}}, } @article{63676, abstract = {{ Purpose The purpose of this paper is to develop new methods of error representation to improve the accuracy and numerical efficiency of a posteriori and goal-oriented adaptive framework of elastoplasticity with Prandtl–Reuss type material laws. Design/methodology/approach To obtain new methods of error representation for a posteriori and goal-oriented error estimators, weak forms of primal and dual problems are investigated starting with the initial boundary value problem (IBVP). Then, we approximate both problems using temporal discretization. Additionally, we introduce a secant form considering the nonlinearity of elasto-plastic constitutive equations, which is approximated by a tangent form. Finally, we obtain numerical primal and dual solutions and their corresponding error approximations of discretized primal and dual problems, allowing to build several goal-oriented a posteriori error estimators on temporal and spatial adaptive refinement by inserting primal solutions, dual solutions and their error approximations as arguments in residuals of both weak forms as well as in the secant form of the bilinear residual. Findings An elasto-plastic material is investigated in a framework of goal-oriented error estimator by using separately several methods of error representation to deal with either temporal or spatial adaptive refinement, as well as with both refinements leading to an effective reduction of computational effort. Specifically, new error representations based on goal-oriented error estimators are presented and obtained from primal and dual residuals, which use only primal solutions or only dual solutions or a combination of primal and dual solutions as arguments. Error representations obtained from primal residuals and evaluated using only primal arguments do not require the formulation of a dual problem. Research limitations/implications The effectiveness of the different proposed methods is illustrated by an example of a perforated sheet for adaptive spatial refinement where new mesh adaptation methods of error representation are compared against existing mesh adaptation methods such as uniform mesh refinement, mesh refinement based on gradient indicators and adjoint-based methods in literature. The framework generates a balanced mesh consisting of fine, medium and coarse elements for accurate results, avoiding a numerically costly simulation with only fine elements. Originality/value All new proposed methods of error representation successfully estimate actual errors during mesh adaptivity. Furthermore, the proposed methods of error representation allow us to obtain significant reduction and equidistribution of spatial error at the end of the mesh adaptivity process. Their application to a framework of goal-oriented error estimation due to time and mesh adaptivity remains an open issue. }}, author = {{Tchomgue Simeu, Arnold and Caylak, Ismail and Ostwald, Richard}}, issn = {{0264-4401}}, journal = {{Engineering Computations}}, pages = {{1--40}}, publisher = {{Emerald}}, title = {{{Error representations for goal-oriented a posteriori error estimation in elasto-plasticity with applications to mesh adaptivity}}}, doi = {{10.1108/ec-12-2023-0975}}, year = {{2026}}, } @article{63784, author = {{Trienens, Dorte and Brüning, Florian and Schöppner, Volker}}, journal = {{kunststoffland NRW report}}, title = {{{Wo Forschung, KI und Praxis aufeinandertreffen}}}, volume = {{03-2025}}, year = {{2026}}, } @article{64187, abstract = {{Carbon fiber-reinforced plastics (CFRPs) have become increasingly significant in recent decades due to their remarkable mechanical properties and lightweight nature. This study aims to advance the understanding and simulation of CFRP behavior through the development of a hyperelastic-plastic-damage homogenization method combined with mean-field theory. The material responses of both the fiber and matrix are modeled using strain energy functions that account for damage evolution, while a complete linearization of the homogenization process is derived to ensure the consistent implementation of the Newton–Raphson iteration scheme in large deformation simulations. The innovative aspect of this work lies in the constitutive linearization for the hyperelastic-plastic-damage formulation within a mean-field homogenization framework, providing an efficient Newton algorithm for modeling the nonlinear behavior of CFRP. A failure criterion for the hyperelastic model of fibers is introduced, along with a damage saturation variable in rate form for the matrix, effectively capturing damage evolution. Through discrete formulations for the homogenization, the proposed model’s capability is demonstrated via three numerical examples and validated against experimental investigations, proving its effectiveness and reliability in simulating CFRP damage.}}, author = {{Zhan, Yingjie and Caylak, Ismail and Ostwald, Richard and Mahnken, Rolf and Barth, Enrico and Uhlmann, Eckart}}, issn = {{1081-2865}}, journal = {{Mathematics and Mechanics of Solids}}, publisher = {{SAGE Publications}}, title = {{{A fully implicit mean-field damage formulation with consistent linearization at large deformations}}}, doi = {{10.1177/10812865261420809}}, year = {{2026}}, } @article{64678, abstract = {{One of the major topics in the modern automotive industry is reducing emissions and increasing the mileage range. To tackle this challenge, on the one hand, modifying the powertrain system is a possibility, and on the other hand, lightweight design offers various possibilities. Multi-Material Design (MMD) involves designing car bodies that combine different materials that require joining. Given the variety of materials, mechanical joining processes are preferred. Especially the current development of the Giga/Mega-casting process concerning aluminium casting and the subsequent mechanical joining illustrates the challenges of this material group. In car production, aluminium castings are mainly made from aluminium-silicon (AlSi) alloys. Ultimately, the alloy system's insufficient ductility leads to crack initiation during mechanical joining. Cast parts are therefore often used in areas of the car body that are exposed to high-pressure loads. For example, self-piercing riveting (SPR) is used due to its high load-bearing capacity. In this study, improved joinability is demonstrated by influencing the microstructure through tailored solidification rates and a developed heat-treatment chain strategy adapted for hypoeutectic AlSi systems. Data on microstructure, mechanical, and joining properties are used to develop a solidification-joining correlation for the SPR process across a range of Si contents and solidification rates. The purpose is to develop the ability to produce suitable aluminium castings with sufficient joinability, thereby improving versatility.}}, 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}}, journal = {{Journal of Manufacturing Processes}}, keywords = {{Mechanical joining, Aluminium, Self-piercing riveting, Casting, Microstructure, Joinability AlSi-alloys}}, publisher = {{Elsevier}}, title = {{{Solidification-joinability correlation of hypoeutectic aluminium casting alloys for self-piercing riveting (SPR)}}}, doi = {{https://doi.org/10.1016/j.jmapro.2026.02.040}}, volume = {{164}}, year = {{2026}}, } @article{63665, author = {{Gude, Maik and Meschut, Gerson and Flügge, Wilko and Fröck, Linda and Wald, Christopher and Neßlinger, Vanessa and Dobrindt-Tittmann, Karsten and Troschitz, Juliane and Neubert, Fynn and Hofmann, Martin and Ostwald, Richard and Mathiszik, Christian and Schmale, Hans Christian and Wallmersperger, Thomas and Grundmeier, Guido}}, issn = {{0143-7496}}, journal = {{International Journal of Adhesion and Adhesives}}, publisher = {{Elsevier BV}}, title = {{{Corrosion of adhesively bonded alloys in maritime environments: A review}}}, doi = {{10.1016/j.ijadhadh.2026.104264}}, volume = {{147}}, year = {{2026}}, } @article{65037, abstract = {{ABSTRACT Homogenization methods simulate heterogeneous materials like composites effectively, but high computational demands can offset their benefits. This work balances accuracy and efficiency by assessing model and discretization errors of the finite element method (FEM) through an adaptive numerical scheme. Two model hierarchies are introduced, combining mean‐field and full‐field methods, and nonuniform transformation field analysis (NTFA) with full‐field methods. Both hierarchies use a full‐field FEM solution of the representative volume element (RVE) as reference. The study highlights the benefits of using effective constitutive equations from mean‐field and full‐field methods as well as NTFA methods, with a goal‐oriented a posteriori error estimator based on duality techniques controlling mesh and model errors in a forwards‐in‐time manner.}}, author = {{Simeu, Arnold Tchomgue and Caylak, Ismail and Ostwald, Richard}}, issn = {{0029-5981}}, journal = {{International Journal for Numerical Methods in Engineering}}, number = {{6}}, publisher = {{Wiley}}, title = {{{Mesh and Model Adaptivity for Multiscale Elastoplastic Models With Prandtl‐Reuss Type Material Laws}}}, doi = {{10.1002/nme.70294}}, volume = {{127}}, year = {{2026}}, } @article{65093, author = {{Marten, Thorsten and Ostermann, Moritz and Behm, Jonathan and Leitenmaier, Samuel}}, issn = {{21991944}}, journal = {{Berufsbildung - Zeitschrift für Theorie-Praxis-Dialog}}, number = {{1}}, pages = {{23--27}}, publisher = {{wbv Publikation}}, title = {{{NeMo.bil - Individualisierter öffentlicher Personennahverkehr - iÖV}}}, doi = {{10.3278/BB2601}}, volume = {{209}}, year = {{2026}}, } @article{65242, abstract = {{Abstract With the growing demand for lightweight solutions to reduce emissions, especially in the transportation, automotive and aerospace sectors, recyclable, continuous fiber-reinforced plastic composite laminates with a thermoplastic matrix are of rising interest. To achieve their maximum mechanical properties, the fiber-matrix adhesion (FMA) is critical. In this work, continuous fiber-reinforced thermoplastic laminates (CFRTPL) with a polypropylene (PP) matrix and twill woven glass fiber fabrics are produced by film stacking. The films used contain different amounts of maleic-anhydride-grafted PP (MA-g-PP) as a coupling agent to produce CFRTPL of different mechanical strengths. To analyze the FMA, the CFRTPL are subjected to Charpy-impact and tensile tests. Additionally, single fiber pull-out tests (SFPT) are conducted to further investigate the effect of MA-g-PP on the FMA. The results of the SFPT show an improvement in apparent interfacial shear strength (AIFSS) when the MA-g-PP content is increased, which can be attributed to an increase in FMA. However, the research shows that MA-g-PP has a low impact on the mechanical properties if the force is applied parallel to the warp and weft threads during tensile testing and the results of the Charpy-impact testing suffer from embrittlement of the matrix material. Subsequently, the results of this study are compared to three-point flexural tests conducted in a previous study. It can be concluded that tensile and impact tests are not suited to investigate FMA on a macroscopic scale, while SFPT and flexural tests provide a better alternative.}}, author = {{Moritzer, Elmar and Brandes, Philipp and Wittler, Maurice and Claes, Leander and Wippermann, Mareen and Haag, Markus and Gries, Thomas and Henning, Bernd}}, issn = {{0930-777X}}, journal = {{International Polymer Processing}}, publisher = {{Walter de Gruyter GmbH}}, title = {{{Fiber-matrix adhesion in glass fiber reinforced thermoplastic composite laminates and its effect on mechanical properties}}}, doi = {{10.1515/ipp-2025-0077}}, year = {{2026}}, } @article{65266, abstract = {{ABSTRACT This work is concerned with the modeling of a cold‐box sand, a composition of sand grains and a resin binder. To this end, experiments are performed, which show the following characteristics: localization phenomena in the form of a shear band, softening behavior in the force‐displacement curve, and asymmetric behavior for compression and tension. To model this complex material behavior, a micromorphic continuum is used. In the present contribution, we focus on the linear‐elastic regime and demonstrate the identifiability of micromorphic material parameters under deliberately induced inhomogeneous deformation states. In addition to the degrees of freedom of a classical continuum, the micromorphic model has additional degrees of freedom, introduced here in a phenomenological sense to represent kinematically enriched deformation modes associated with the granular microstructure. Accordingly, the micromorphic fields are not interpreted as a separate physical scale (e.g., “binder” vs. “grains”), but as an effective continuum description at the specimen scale. This contribution addresses parameter identification for a micromorphic model of cold‐box sand, with a clear separation between homogeneous deformation states governing classical elastic parameters and inhomogeneous states required to activate and identify micromorphic length‐scale parameters. The main challenge lies in identifying the micro material parameters. To determine these, the corresponding gradient terms in the constitutive formulation must be triggered via properly tuned experiments. Micro‐parameter identification is demonstrated using synthetic data generated from a boundary‐value problem with inhomogeneous displacement fields. The chosen benchmark enables controlled activation of gradient terms and thereby renders optimization‐based identification of micromorphic parameters feasible. The synthetic example is deliberately chosen to assess feasibility and identifiability under controlled conditions, thereby isolating micromorphic identifiability aspects from experimental uncertainties. The novelty of the contribution lies in explicitly linking micromorphic parameter identifiability to kinematic inhomogeneity, and in demonstrating this link within a tractable forward– inverse setting for a linear‐elastic micromorphic continuum.}}, author = {{Börger, Alexander and Mahnken, Rolf and Caylak, Ismail and Ostwald, Richard}}, issn = {{1617-7061}}, journal = {{Proceedings in Applied Mathematics and Mechanics}}, number = {{2}}, publisher = {{Wiley}}, title = {{{Aspects of Parameter Identification for a Micromorphic Continuum applied to a Cold‐Box Sand}}}, doi = {{10.1002/pamm.70093}}, volume = {{26}}, year = {{2026}}, } @inbook{59905, abstract = {{Um die international und national beschlossenen Klimaziele zu erreichen, müssen die verkehrsbedingten Emissionen in der Bundesrepublik Deutschland drastisch reduziert werden. Hierzu bedarf es einer umfassenden Mobilitätswende, welche die Etablierung emissionsärmerer und effizienterer Mobilitätsformen umfasst. Ein Lösungsansatz können on-demand Dienste bieten, die den öffentlichen Personennahverkehr bedarfsgerecht gestalten und so dessen Akzeptanz steigern. Zahlreiche bisher eingeführte on-demand Dienste mussten jedoch nach Beendigung des Projekt- bzw. Förderzeitraums wieder eingestellt werden. Maßgebliche Herausforderungen waren die Integration der Dienste in die bestehenden ÖPNV- und Mobilitäts-Strukturen sowie teilweise damit einhergehende ökonomische Aspekte. In diesem Beitrag wird eine Methode vorgestellt, welche neben der Einführung neuartiger Mobilitätsdienste auch die Entwicklung eines nachhaltigen Mobilitäts-Ökosystems anstrebt. Der Fokus liegt dabei auf ländlich geprägten Regionen und ihren besonderen Herausforderungen im Bereich des öffentlichen Nahverkehrs. Die Methode beschreibt ein fünf-phasiges Handlungsschema, in welchem Potenziale bestehender Strukturen genutzt, Mobilitäts-Stakeholder eingebunden und verhärtete Mobilitätsverhalten allmählich positiv verändert werden. Anhand der Initiative Neue Mobilität Paderborn wird aufgezeigt, dass mithilfe der Methode erste Schritte hin zu einem Mobilitäts-Ökosystem absolviert werden können. Darüber hinaus werden Einführungsszenarien für die neuartige, sich noch in der Entwicklung befindliche Mobilitätslösung NeMo.bil in einer Beispielregion erarbeitet.}}, author = {{Behm, Jonathan and Ostermann, Moritz and Bomm, Julian and Rahmann, Sören and Tröster, Thomas and Marten, Thorsten}}, booktitle = {{New Players in Mobility}}, isbn = {{9783658464844}}, location = {{Duisburg}}, publisher = {{Springer Fachmedien Wiesbaden}}, title = {{{Einführungsstrategien nachhaltiger on-demand Mobilitätkonzepte im öffentlichen Nahverkehr}}}, doi = {{10.1007/978-3-658-46485-1_36}}, year = {{2025}}, } @article{60040, author = {{Pfeffer, Nina and Jäger, Stefanie Nicole and Kaiser, Maximilian Alexander and Meyer, Thomas and Stark, Andreas and Höppel, Heinz Werner}}, issn = {{0921-5093}}, journal = {{Materials Science and Engineering: A}}, publisher = {{Elsevier BV}}, title = {{{Enhancing mechanical strength of Ti-6Al-4V sheet material by short-time sub-β-transus solution heat treatment and additional short-time annealing}}}, doi = {{10.1016/j.msea.2025.147787}}, volume = {{926}}, year = {{2025}}, } @phdthesis{59908, author = {{Gevers, Karina}}, isbn = {{978-3-8440-9978-2 }}, keywords = {{Infrarotschweißen, Zeitfestigkeit, Polyamide}}, pages = {{216}}, publisher = {{Shaker Verlag}}, title = {{{Zeitfestigkeit von infrarotgeschweißten gefüllten Polyamiden }}}, year = {{2025}}, } @article{60081, author = {{Naumann, Marius and Ostermann, Moritz and Buchenau, Nadja and Oetzel, Jannik and Schlosser, Florian and Meschede, Henning and Tröster, Thomas}}, issn = {{0196-8904}}, journal = {{Energy Conversion and Management}}, publisher = {{Elsevier BV}}, title = {{{Energy efficiency improvement for decarbonization in manufacturing industry: A review}}}, doi = {{10.1016/j.enconman.2025.119763}}, volume = {{338}}, year = {{2025}}, } @article{63440, author = {{Moritzer, Elmar and Brandes, Philipp and Westphal, Max Siegfried and Claes, Leander and Wippermann, Mareen and Düchting, Julia and Henning, Bernd}}, journal = {{WAK Jahresmagazin}}, keywords = {{Faser-Kunststoff-Verbunde (FKV), Faserverstärkte Kunststoffe (FVK), Organobleche, Ultraschall}}, pages = {{26–29}}, title = {{{ZERSTÖRUNGSFREIE ULTRASCHALLPRÜFUNG VON ORGANOBLECHEN}}}, volume = {{2025}}, year = {{2025}}, } @article{60017, author = {{Skolik, Alexander Marcus and zur Heiden, Philipp and Donner, Johannes Aurelius Tamino and Priefer, Jennifer}}, journal = {{ECIS 2025 Proceedings}}, location = {{Amman, Jordan}}, title = {{{Igniting Knowledge Management for Assistance Systems in Maintenance: A Method for Knowledge Gathering}}}, volume = {{2}}, year = {{2025}}, } @inproceedings{63437, author = {{Beckmann, Johanna and Bachmann, Andre and Brandes, Philipp and Marten, Thorsten and Tröster, Thomas and Moritzer, Elmar}}, booktitle = {{24th International Conference on Composite Materials (ICCM24)}}, keywords = {{Faser-Kunststoff-Verbunde (FKV), Faserverstärkte Kunststoffe (FVK), Organobleche}}, publisher = {{The University of Delaware}}, title = {{{Validation of Possible Applications of Flake Laminates for Recycling of PA6-CF Production Scrap}}}, doi = {{https://doi.org/10.5281/zenodo.18597865}}, year = {{2025}}, } @article{58163, abstract = {{Fibre-reinforced polymers are increasingly used due to their high specific strength, making them suitable for local sheet metal reinforcement. This allows improved overall mechanical properties with reduced wall thickness of the sheet metal part and, thus, lower weight of the components. One of the main focuses of research into such hybrid structures is on the adhesive properties and the respective failure behaviour of the interfaces. Generally, the failure behaviour under the influence of mechanical loads can be divided into adhesive, cohesive and mixed-mode failure. The correlation between observed failure behaviour and adhesion properties of the hybrid composite materials is analysed in detail in this work. The hybrid composite consists of an aluminium sheet of the alloy EN AW‑6082 T6 and thermoset carbon fibre-reinforced plastic (CFRP) prepreg. The aluminium sheet was laser pretreated before hybrid production to improve the adhesion properties. The specimens studied were produced by the prepreg pressing process, in which the components are cured and joined simultaneously. The influences of the thickness of the CFRP part, the layup, the fibre orientation at the boundary layer, and the laser pretreatment parameters on the properties of the hybrid joints were investigated.}}, author = {{Wu, Shuang and Delp, Alexander and Freund, Jonathan and Walther, Frank and Haubrich, Jan and Löbbecke, Miriam and Tröster, Thomas}}, issn = {{0021-8464}}, journal = {{The Journal of Adhesion}}, keywords = {{Prepreg pressing process, hybrid joints, laser surface pretreatment, intrinsic manufacturing, CFRP, aluminium, materials engineering}}, pages = {{1--26}}, publisher = {{Informa UK Limited}}, title = {{{Correlation between interlaminar shear strength of CFRP and joint strength of aluminium-CFRP hybrid joints}}}, doi = {{10.1080/00218464.2024.2439956}}, year = {{2025}}, } @article{59872, abstract = {{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.}}, author = {{Neuser, Moritz and Schlichter, Malte Christian and Hoyer, Kay-Peter and Bobbert, Mathias and Meschut, Gerson and Schaper, Mirko}}, journal = {{44th Conference of the International Deep Drawing Research Group (IDDRG 2025)}}, keywords = {{Joining, Casting, Self-pierce riveting, Aluminium casting alloy}}, location = {{Lissabon (Portugal)}}, title = {{{Mechanical joinability of microstructurally graded structural components manufactured from hypoeutectic aluminium casting alloys}}}, doi = {{10.1051/matecconf/202540801081}}, volume = {{408}}, year = {{2025}}, } @inproceedings{59441, abstract = {{Abstract. Accurate Finite Element Modeling (FEM) of joints is essential in the design of complex mechanical systems such as automotive body-in-white (BIW) structures, as it plays a critical role in evaluating their performance. Although well-established techniques exist for modeling rotationally symmetric joints, there remains a significant gap in effectively modeling non-rotationally symmetric joints. These joints are particularly relevant in the automotive BIW, where they can better accommodate anisotropic loading conditions. In this study, strategies for modeling non-rotationally symmetric joints were explored using finite element simulations in LS-DYNA. The findings demonstrate that discrete beam elements can capture the anisotropic characteristics of such joints. Two models were tested: a single-beam model for stiffness periodicity every 90°, and a three-beam model for stiffness periodicity every 120°. Force responses, stress distribution, and sheet bending behaviors were analyzed, confirming that discrete beam elements can accurately represent direction-dependent stiffness. These results establish a foundation for developing advanced joint modeling strategies in complex mechanical systems.}}, author = {{Devulapally, Deekshith Reddy and Tröster, Thomas}}, booktitle = {{Materials Research Proceedings}}, issn = {{2474-395X}}, location = {{Paderborn}}, publisher = {{Materials Research Forum LLC}}, title = {{{Modelling strategies for non-rotationally symmetric joints}}}, doi = {{10.21741/9781644903551-21}}, volume = {{52}}, year = {{2025}}, }