@article{58342, author = {{Bode, Christoph and Goetz, Stefan and Wartzack, Sandro}}, issn = {{2212-8271}}, journal = {{Procedia CIRP}}, pages = {{151--156}}, publisher = {{Elsevier BV}}, title = {{{On the transferability of nominal surrogate models to uncertainty consideration of clinch joint characteristics}}}, doi = {{10.1016/j.procir.2024.10.027}}, volume = {{129}}, year = {{2024}}, } @inproceedings{51739, author = {{Weiß, Deborah and Duffe, Tobias and Buczek, Moritz and Kullmer, Gunter and Schramm, Britta}}, location = {{Berlin}}, publisher = {{Deutscher Verband für Materialforschung und -prüfung e.V.}}, title = {{{Bruchmechanische Untersuchung des Dualphasenstahls HCT590X unter Temperatureinfluss}}}, doi = {{10.48447/WP-2023-244}}, year = {{2023}}, } @inproceedings{38509, author = {{Brosius, Alexander and Ewenz, Lars and Stephan, Richard and Zimmermann, Martina}}, booktitle = {{Tagung Werkstoffprüfung 2022}}, editor = {{Zimmermann, Martina}}, isbn = {{978-3-88355-430-3}}, location = {{Dresden}}, publisher = {{Deutsche Gesellschaft für Materialkunde e.V. (DGM)}}, title = {{{Anrisserkennung an geclinchten Proben während einer zyklischen Belastung unter Nutzung eines Scanning Laser Doppler Vibrometers}}}, year = {{2023}}, } @inproceedings{38511, author = {{Ewenz, Lars and Kuczyk, Martin and Schöne, S. and Zimmermann, Martina}}, booktitle = {{Tagung Werkstoffprüfung 2022}}, editor = {{Zimmermann, Martina}}, location = {{Dresden}}, publisher = {{Deutsche Gesellschaft für Materialkunde e.V. (DGM)}}, title = {{{Ableitung flacher Probengeometrien zur Abbildung mehraxialer Spannungszustände in Clinchverbindungen unter zyklischer Beanspruchung}}}, year = {{2023}}, } @inproceedings{38507, author = {{Ewenz, Lars and Kühne, R. and Schöne, S. and Zimmermann, Martina}}, booktitle = {{Tagung Werkstoffprüfung 2022}}, editor = {{Zimmermann, Martina}}, publisher = {{Deutsche Gesellschaft für Materialkunde e.V. (DGM)}}, title = {{{Untersuchungen zum Geometrie- und Frequenzeinfluss bei der Ermittlung zyklischer Kennwerte geclinchter Überlappverbindungen}}}, year = {{2023}}, } @inproceedings{60304, abstract = {{The focus towards multi-material and lightweight assemblies, driven by legal requirements on reducing emissions and energy consumptions, reveals important drawbacks and disadvantages of established joining processes, such as welding. In this context, mechanical joining technologies, such as clinching, are becoming more and more relevant especially in the automotive industry. However, the availability of only few standards and almost none systematic design methods causes a still very time- and cost-intensive assembly development process considering mainly expert knowledge and a considerable amount of experimental studies. Motivated by this, the presented work introduces a novel approach for the methodical design and dimensioning of mechanically clinched assemblies. Therefore, the utilization of regression models, such as machine learning algorithms, combined with manufacturing knowledge ensures a reliable estimation of individual clinched joint characteristics. In addition, the implementation of an engineering workbench enables the following data-driven and knowledge-based generation of high-quality initial assembly designs already in early product development phases. In a subsequent analysis and adjustment, these designs are being improved while guaranteeing joining safety and loading conformity. The presented results indicate that the methodological approach can pave the way to a more systematic design process of mechanical joining assemblies, which can significantly shorten the required number of iteration loops and therefore the product development time.}}, author = {{Zirngibl, Christoph and Martin, Sven and Steinfelder, Christian and Schleich, Benjamin and Tröster, Thomas and Brosius, Alexander and Wartzack, Sandro}}, booktitle = {{Materials Research Proceedings}}, issn = {{2474-395X}}, keywords = {{Joining, Structural Analysis, Machine Learning}}, location = {{Erlangen-Nürnberg}}, publisher = {{Materials Research Forum LLC}}, title = {{{Methodical approach for the design and dimensioning of mechanical clinched assemblies}}}, doi = {{10.21741/9781644902417-23}}, volume = {{25}}, year = {{2023}}, } @inproceedings{60302, abstract = {{The combination of the mechanical properties of a clinched joint and of the material surrounding the joint determine the resulting properties of the component and joint. The cause and effect relationships between the joint and the joint environment offers the possibility of a specific modification through an adaptation in the design process. In order to identify these cause and effect relationships and resulting interactions experimentally, numerous of experiments are required. In this publication, a concept for the automated manufacturing of head tensile test and shear tensile test specimens – from cutting to clinching – by using a punch laser machine is presented. Based on a full-factorial experimental design, the parameters change of the properties of the joint environment by beading and change of the punch displacement are addressed. The influence on the properties of the clinched specimen is evaluated based on the variables Stiffness, force at the beginning of yielding and maximum force at head tensile loading and shear tensile loading. In addition, the geometric quality parameters of neck thickness, interlock and bottom thickness are evaluated. The relationships can be used to apply uniform loads to joints in joined structures to counteract oversizing.}}, author = {{Steinfelder, Christian and Brosius, Alexander}}, booktitle = {{Materials Research Proceedings}}, issn = {{2474-395X}}, keywords = {{Sheet Metal, Joining, Stiffness}}, location = {{Erlangen-Nürnberg}}, publisher = {{Materials Research Forum LLC}}, title = {{{Experimental investigation of the cause and effect relationships between the joint and the component during clinching}}}, doi = {{10.21741/9781644902417-19}}, volume = {{25}}, year = {{2023}}, } @article{34213, abstract = {{In this paper, a study based on experimental and numerical simulations is performed to analyze fatigue cracks in clinched joints. An experimental investigation is conducted to determine the failure modes of clinched joints under cyclic loading at different load amplitudes with single-lap shear tests. In addition, numerical FEM simulations of clinching process and subsequent shear loading are performed to support the experimental investigations by analyzing the state of stresses at the location of failure. An attempt is made to explain the location of crack initiation in the experiments using evaluation variables such as contact shear stress and maximum principal stress.}}, author = {{Ewenz, L. and Bielak, Christian Roman and Otroshi, Mortaza and Bobbert, Mathias and Meschut, Gerson and Zimmermann, M.}}, issn = {{0944-6524}}, journal = {{Production Engineering}}, keywords = {{Industrial and Manufacturing Engineering, Mechanical Engineering}}, number = {{2-3}}, pages = {{305--313}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Numerical and experimental identification of fatigue crack initiation sites in clinched joints}}}, doi = {{10.1007/s11740-022-01124-z}}, volume = {{16}}, year = {{2022}}, } @inproceedings{34415, abstract = {{Challenges in the development of resource-efficient lightweight designs, such as emission and cost targets in production, lead to an increasing demand for environmentally friendly and fast joining processes. Therefore, cold-forming mechanical joining techniques provide an energy-efficient alternative in comparison to established processes, such as spot welding. However, to ensure a sufficient reliability of the product design, not only the selection of an appropriate manufacturing and joining method, but also the suitable dimensioning and validation of the entire joining process is a crucial step. In this context, thermal processes offer a large number of design principles while mechanical joining methods mainly require extensive experimental tests and the inclusion of expert knowledge. Although few contributions already investigated the data-based analysis of mechanical joints, a system for the requirement- and manufacturing-oriented dimensioning of joining components, such as different profiles and blanks, in combination with the estimation of joint properties is not available yet. Motivated by this lack, this contribution introduces an engineering workbench for the support of design engineers in the early development phases of the knowledge and data-based design of mechanical joining connections using clinching as an example. In this regard, the approach is demonstrated involving a similar material and sheet thickness combination with static loads.}}, author = {{Zirngibl, Christoph and Sauer, Christopher and Schleich, Benjamin and Wartzack, Sandro}}, booktitle = {{Volume 2: 42nd Computers and Information in Engineering Conference (CIE)}}, publisher = {{American Society of Mechanical Engineers}}, title = {{{Knowledge and Data-Based Design and Dimensioning of Mechanical Joining Connections}}}, doi = {{10.1115/detc2022-89172}}, year = {{2022}}, } @article{34417, abstract = {{Given strict emission targets and legal requirements, especially in the automotive industry, environmentally friendly and simultaneously versatile applicable production technologies are gaining importance. In this regard, the use of mechanical joining processes, such as clinching, enable assembly sheet metals to achieve strength properties similar to those of established thermal joining technologies. However, to guarantee a high reliability of the generated joint connection, the selection of a best-fitting joining technology as well as the meaningful description of individual joint properties is essential. In the context of clinching, few contributions have to date investigated the metamodel-based estimation and optimization of joint characteristics, such as neck or interlock thickness, by applying machine learning and genetic algorithms. Therefore, several regression models have been trained on varying databases and amounts of input parameters. However, if product engineers can only provide limited data for a new joining task, such as incomplete information on applied joining tool dimensions, previously trained metamodels often reach their limits. This often results in a significant loss of prediction quality and leads to increasing uncertainties and inaccuracies within the metamodel-based design of a clinch joint connection. Motivated by this, the presented contribution investigates different machine learning algorithms regarding their ability to achieve a satisfying estimation accuracy on limited input data applying a statistically based feature selection method. Through this, it is possible to identify which regression models are suitable to predict clinch joint characteristics considering only a minimum set of required input features. Thus, in addition to the opportunity to decrease the training effort as well as the model complexity, the subsequent formulation of design equations can pave the way to a more versatile application and reuse of pretrained metamodels on varying tool configurations for a given clinch joining task.}}, author = {{Zirngibl, Christoph and Schleich, Benjamin and Wartzack, Sandro}}, issn = {{2673-2688}}, journal = {{AI}}, keywords = {{Industrial and Manufacturing Engineering}}, number = {{4}}, pages = {{990--1006}}, publisher = {{MDPI AG}}, title = {{{Estimation of Clinch Joint Characteristics Based on Limited Input Data Using Pre-Trained Metamodels}}}, doi = {{10.3390/ai3040059}}, volume = {{3}}, year = {{2022}}, } @article{30624, abstract = {{In addition to brazing and welding processes, mechanical joining processes such as clinching are increasingly being used. Clinch joints offer an advantage over metallurgical joining processes by giving the possibility of joining different material combinations without typical drawbacks. Thereby clinching offers an enormous advantage for lightweight construction. An additional benefit is a great variability in the geometric shapes of the toolsets, which ensure optimum adaptation of the clinching process on variations of the joining elements such as e.g. the sheet thickness. However, the vast variability is also one of the major challenges regarding the prediction of the joint reliability. In the work presented, the effect of different toolset geometries was investigated with a particular focus on the interaction between geometrical features and deformation-induced microstructural changes. Light optical and electron microscopy techniques, as well as micro-hardness measurements, were performed. The results were evaluated and discussed concerning the material's deformation behavior, the change in geometrical shape and the microstructural evolution due to the different tool geometries. The findings point out the main influence factors regarding the mechanical properties in general and the fatigue behavior in particular.}}, author = {{Ewenz, L. and Kuczyk, M. and Zimmermann, M.}}, journal = {{Journal of Advanced Joining Processes}}, title = {{{Effect of the tool geometry on microstructure and geometrical features of clinched aluminum}}}, doi = {{10.1016/j.jajp.2021.100091}}, volume = {{5}}, year = {{2022}}, } @article{30629, abstract = {{Clinching is a joining process that is becoming more and more important in industry due to the increasing use of multi-material designs. Despite the already widespread use of the process, there is still a need for research to understand the mechanisms and design of clinched joints. In contrast to the tool parameters, process and material disturbances have not yet been investigated to a relatively large extent. However, these also have a great influence on the properties and applicability of clinching. The effect of process disturbances on the clinched joint are investigated with numerical and experimental methods. The investigated process variations are the history of the sheets using the pre-hardening of the material, different sheet thicknesses, sheet arrangements and punch strokes. For the consideration of the material history, a specimen geometry for pre-stretching specimens in uniaxial tension is used, from which the pre-stretched secondary specimens are taken. A finite element model is set up for the numerical investigations. Suitable clinching tools are selected. With the simulation, selected process influences can be examined. The effort of the numerical investigations is considerably reduced with the help of a statistical experimental design according to Taguchi. To confirm the simulation results, experimental investigations of the clinch point geometry by using micrographs and the shear strength of the clinched joint are performed. The analysis of the influence of difference disturbance factors on the clinching process demonstrate the importance of the holistic view of the clinching process.}}, author = {{Steinfelder, C. and Acksteiner, J. and Guilleaume, C. and Brosius, A.}}, journal = {{Production Engineering}}, title = {{{Analysis of the interactions between joint and component properties during clinching}}}, doi = {{10.1007/s11740-021-01102-x}}, year = {{2022}}, } @article{34253, abstract = {{Lightweight construction has increasingly become the focus of scientific research in recent years, not least due to the constantly increasing fuel price, which is a key factor in the economic viability of many companies. In this respect, the use of hybrid structures, made of dissimilar materials offers many advantages. However, such hybrid structures often have undesirable side effects. For example, brittle intermetallic phases are formed when aluminum and steel are welded. Clinching as a mechanical joining process does not produce such intermetallic phases since the connection is realized through form and force closure. In this process, a punch passes through two or more sheets and forms them into a permanent joint in a die. In the present work, the corrosion phenomena of an aluminum-steel clinched joint have been investigated by both experiments and numerical simulations in order to explain the superior fatigue behavior of pre-corroded joints. Therefore, the clinched joints have been corroded by a three-week salt-spray test. In addition, the electric potential and the von Mises stress are calculated under the assumption of a static loading. The results of both experiments and numerical simulations can explain the improvement in the fatigue behavior of the corroded specimens. This phenomenon can be attributed to the accumulation of corrosion products in small gaps between the joined metal sheets.}}, author = {{Harzheim, Sven and Ewenz, Lars and Zimmermann, Martina and Wallmersperger, Thomas}}, issn = {{2666-3309}}, journal = {{Journal of Advanced Joining Processes}}, keywords = {{Mechanical Engineering, Mechanics of Materials, Engineering (miscellaneous), Chemical Engineering (miscellaneous)}}, publisher = {{Elsevier BV}}, title = {{{Corrosion Phenomena and Fatigue Behavior of Clinched Joints: Numerical and Experimental Investigations}}}, doi = {{10.1016/j.jajp.2022.100130}}, volume = {{6}}, year = {{2022}}, } @article{34252, abstract = {{Clinching is the manufacturing process of joining two or more metal sheets under high plastic deformation by form and force closure without thermal support and auxiliary parts. Clinch connections are applicable to difficult-to-join hybrid material combinations, such as steel and aluminum. Therefore, this technology is interesting for the application of AISI 304 components, as this material is widely used as a highly formable sheet material. A characteristic feature of AISI 304 is its metastability, i.e., the face-centered cubic (fcc) γ-austenite can transform into a significantly stronger body-centered cubic (bcc) α’-martensite under plastic deformation. This work investigates the effect of heat treatment—a process that involves the formation of an oxidation layer on the sheet surface—on the forming process during joining and the resulting mechanical properties of clinch joints made from AISI 304. For this purpose, different joints made from non-heat treated and heat-treated sheets were examined using classical metallography and advanced SEM techniques, accompanied by further investigations, such as hardness and feritscope measurements. The shear tensile strength was determined, and the fracture behavior of the samples was investigated. Clear influences of heat-treatment-induced surface roughness on the joint geometry and strength were observed.}}, author = {{Zeuner, André Till and Ewenz, Lars and Kalich, Jan and Schöne, Sebastian and Füssel, Uwe and Zimmermann, Martina}}, issn = {{2075-4701}}, journal = {{Metals}}, keywords = {{General Materials Science, Metals and Alloys}}, number = {{9}}, publisher = {{MDPI AG}}, title = {{{The Influence of Heat Treatment on the Microstructure, Surface Roughness and Shear Tensile Strength of AISI 304 Clinch Joints}}}, doi = {{10.3390/met12091514}}, volume = {{12}}, year = {{2022}}, } @article{34249, abstract = {{The trend towards lightweight design, driven by increasingly stringent emission targets, poses challenges to conventional joining processes due to the different mechanical properties of the joining partners used to manufacture multi-material systems. For this reason, new versatile joining processes are in demand for joining dissimilar materials. In this regard, pin joining with cold extruded pin structures is a relatively new, two-stage joining process for joining materials such as high-strength steel and aluminium as well as steel and fibre-reinforced plastic to multi-material systems, without the need for auxiliary elements. Due to the novelty of the process, there are currently only a few studies on the robustness of this joining process available. Thus, limited statements on the stability of the joining process considering uncertain process conditions, such as varying material properties or friction values, can be provided. Motivated by this, the presented work investigates the influence of different uncertain process parameters on the pin extrusion as well as on the joining process itself, carrying out a systematic robustness analysis. Therefore, the methodical approach covers the complete process chain of pin joining, including the load-bearing capacity of the joint by means of numerical simulation and data-driven methods. Thereby, a deeper understanding of the pin joining process is generated and the versatility of the novel joining process is increased. Additionally, the provision of manufacturing recommendations for the forming of pin joints leads to a significant decrease in the failure probability caused by ploughing or buckling effects.}}, author = {{Römisch, David and Zirngibl, Christoph and Schleich, Benjamin and Wartzack, Sandro and Merklein, Marion}}, issn = {{2504-4494}}, journal = {{Journal of Manufacturing and Materials Processing}}, keywords = {{Industrial and Manufacturing Engineering, Mechanical Engineering, Mechanics of Materials}}, number = {{5}}, publisher = {{MDPI AG}}, title = {{{Robustness Analysis of Pin Joining}}}, doi = {{10.3390/jmmp6050122}}, volume = {{6}}, year = {{2022}}, } @inbook{34209, abstract = {{Predicting the durability of components subjected to mechanical load under environmental conditions leading to corrosion is one of the most challenging tasks in mechanical engineering. The demand for precise predictions increases with the desire of lightweight design in transportation due to environmental protection. Corrosion with its manifold of mechanisms often occurs together with the production of hydrogen by electrochemical reactions. Hydrogen embrittlement is one of the most feared damage mechanisms for metal constructions often leading to early and unexpected failure. Until now, predictions are mostly based on costly experiments. Hence, a rational predictive model based on the fundamentals of electrochemistry and damage mechanics has to be developed in order to reduce the costs. In this work, a first model approach based on classical continuum damage mechanics is presented to couple both, the damage induced by the mechanical stress and the hydrogen embrittlement. An elaborated two-scale model based on the selfconsistent theory is applied to describe the mechanical damage due to fatigue. The electrochemical kinetics are elucidated through the Langmuir adsorption isotherm and the diffusion equation to consider the impact of hydrogen embrittlement on the fatigue. The modeling of the mechanism of hydrogen embrittlement defines the progress of damage accumulation due to the electrochemistry. The durability results like the S-N diagram show the influence of hydrogen embrittlement by varying, e.g. the fatigue frequency or the stress ratio.}}, author = {{Shi, Yuhao and Harzheim, Sven and Hofmann, Martin and Wallmersperger, Thomas}}, booktitle = {{Material Modeling and Structural Mechanics}}, isbn = {{9783030976743}}, issn = {{1869-8433}}, keywords = {{Hydrogen embrittlement, Fatigue, Continuum damage mechanics, Numerical simulation, Multi-field problem}}, publisher = {{Springer International Publishing}}, title = {{{A Damage Model for Corrosion Fatigue Due to Hydrogen Embrittlement}}}, doi = {{10.1007/978-3-030-97675-0_9}}, year = {{2022}}, } @article{34414, abstract = {{Given a steadily increasing demand on multi-material lightweight designs, fast and cost-efficient production technologies, such as the mechanical joining process clinching, are becoming more and more relevant for series production. Since the application of such joining techniques often base on the ability to reach similar or even better joint loading capacities compared to established joining processes (e.g., spot welding), few contributions investigated the systematic improvement of clinch joint characteristics. In this regard, the use of data-driven methods in combination with optimization algorithms showed already high potentials for the analysis of individual joints and the definition of optimal tool configurations. However, the often missing consideration of uncertainties, such as varying material properties, and the related calculation of their impact on clinch joint properties can lead to poor estimation results and thus to a decreased reliability of the entire joint connection. This can cause major challenges, especially for the design and dimensioning of safety-relevant components, such as in car bodies. Motivated by this, the presented contribution introduces a novel method for the robust estimation of clinch joint characteristics including uncertainties of varying and versatile process chains in mechanical joining. Therefore, the utilization of Gaussian process regression models is demonstrated and evaluated regarding the ability to achieve sufficient prediction qualities.}}, author = {{Zirngibl, Christoph and Schleich, Benjamin and Wartzack, Sandro}}, issn = {{0268-3768}}, journal = {{The International Journal of Advanced Manufacturing Technology}}, keywords = {{Industrial and Manufacturing Engineering, Computer Science Applications, Mechanical Engineering, Software, Control and Systems Engineering}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Robust estimation of clinch joint characteristics based on data-driven methods}}}, doi = {{10.1007/s00170-022-10441-7}}, year = {{2022}}, } @article{34261, abstract = {{Mechanical clinching is used to create lightweight hybrid structures. In order to estimate the service life of clinched components, its fatigue properties need to be known under different mechanical loading conditions. In addition to fatigue, corrosion is another factor that affects the fatigue life of clinched joints. In the literature, many corrosion and high-cycle fatigue damage models exist. However, little is known about how both phenomena interact in clinched joints. In this article, the influence of galvanic corrosion on clinched EN AW-6014/HCT590X + Z sheets on the fatigue life is investigated by means of numerical simulations and experimental results. An accurate prediction of the Wöhler lines of non-corroded and pre-corroded clinched specimens is shown.}}, author = {{Harzheim, Sven and Hofmann, Martin and Wallmersperger, Thomas}}, issn = {{1537-6494}}, journal = {{Mechanics of Advanced Materials and Structures}}, keywords = {{Mechanical Engineering, Mechanics of Materials, General Materials Science, General Mathematics, Civil and Structural Engineering}}, pages = {{1--6}}, publisher = {{Informa UK Limited}}, title = {{{Numerical fatigue life prediction of corroded and non-corroded clinched joints}}}, doi = {{10.1080/15376494.2022.2140233}}, year = {{2022}}, } @article{34215, abstract = {{Clinching as a mechanical joining technique allows a fast and reliable joining of metal sheets in large-scale production. An efficient design and dimensioning of clinched joints requires a holistic understanding of the material, the joining process and the resulting properties of the joint. In this paper, the process chain for clinching metal sheets is described and experimental techniques are proposed to analyze the process-microstructure-property relationships from the sheet metal to the joined structure. At the example of clinching aluminum EN AW 6014, characterization methods are applied and discussed for the following characteristics: the mechanical properties of the sheet materials, the tribological behavior in the joining system, the joining process and the resulting material structure, the load-bearing behavior of the joint, the damage and degradation as well as the service life and crack growth behavior. The compilation of the characterization methods gives an overview on the advantages and weaknesses of the methods and the multiple interactions of material, process and properties during clinching. In addition, the results of the analyses on EN AW 6014 can be applied for parameterization and validation of simulations.}}, author = {{Kupfer, Robert and Köhler, Daniel and Römisch, David and Wituschek, Simon and Ewenz, Lars and Kalich, Jan and Weiß, Deborah and Sadeghian, Behdad and Busch, Matthias and Krüger, Jan Tobias and Neuser, Moritz and Grydin, Olexandr and Böhnke, Max and Bielak, Christian Roman and Troschitz, Juliane}}, issn = {{2666-3309}}, journal = {{Journal of Advanced Joining Processes}}, keywords = {{Mechanical Engineering, Mechanics of Materials, Engineering (miscellaneous), Chemical Engineering (miscellaneous)}}, publisher = {{Elsevier BV}}, title = {{{Clinching of Aluminum Materials – Methods for the Continuous Characterization of Process, Microstructure and Properties}}}, doi = {{10.1016/j.jajp.2022.100108}}, volume = {{5}}, year = {{2022}}, } @inproceedings{35271, author = {{Weiß, Deborah and Schramm, Britta}}, booktitle = {{Procedia Structural Integrity}}, issn = {{2452-3216}}, keywords = {{General Engineering, Energy Engineering and Power Technology}}, location = {{Madeira}}, pages = {{879--885}}, publisher = {{Elsevier BV}}, title = {{{Fracture mechanical investigation of preformed metal sheets using a novel CC-specimen}}}, doi = {{10.1016/j.prostr.2022.12.111}}, volume = {{42}}, year = {{2022}}, }