@article{54797,
abstract = {{Focusing on upcoming challenges in lightweight design, such as increasing emission targets or novel multimaterial connections, versatile applicable and environmentally friendly production technologies are crucial. In this context, mechanical joining technology clinching offers a fast and energy-efficient procedure for assembling sheet metals, being a proper alternative to established joining methods, such as spot welding. However, the design of clinch points is a challenge, which is partly supported by numerical or data-based approaches for optimal tool dimensions assuring proper joint characteristics. While this is usually done for an ideal environment, real joining processes are characterized by multiple inevitably varying parameters, e.g. of the material, which have a significant impact on the quality of clinch points. Therefore, this contribution addresses the current gap by analyzing the effect of parameter variations or uncertainties on the resulting joint characteristics and studying the impact of the nominal tool design. Thus, an efficient meta-model-based variation simulation procedure is proposed and used for analyzing the effect of different tool design configurations and variation scenarios. Based on the results, it was found that varying process parameters have a strong impact on the resulting joint characteristics, whereby the effect significantly depends on the nominal tool design. This reveals the potential for a robust tool design and implies that the nominal tool design and the tolerancing of parameters should be done simultaneously for a reliable virtual joining point design without extensive iterations and physical tests.}},
author = {{Zirngibl, C and Goetz, S and Wartzack, S}},
issn = {{0954-4089}},
journal = {{Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering}},
publisher = {{SAGE Publications}},
title = {{{Influence of process variations on clinch joint characteristics considering the effect of the nominal tool design}}},
doi = {{10.1177/09544089241259347}},
year = {{2024}},
}
@inproceedings{56682,
author = {{Einwag, Jonathan-Markus and Goetz, Stefan and Wartzack, Sandro}},
booktitle = {{DS 133: Proceedings of the 35th Symposium Design for X (DFX2024)}},
publisher = {{The Design Society}},
title = {{{Approach for the Reliable and Virtual Design of Mechanical Joints in an Uncertain Environment}}},
doi = {{10.35199/dfx2024.23}},
year = {{2024}},
}
@article{61412,
abstract = {{AbstractMechanical clinching is a frequently used joining method for technical components. These joints are usually weak spots. Here, corrosion and fatigue are decisive influencing factors for the assessment of the service life of such joints. Corrosion generally leads to material deterioration and thus to premature failure of the joints. Under certain circumstances, however, corrosion can lead to an increased fatigue life. While this effect has not yet been fully understood, the present work provides a possible explanation and a modeling approach to predict the fatigue life of precorroded clinched joints. The increased fatigue life is observed when the clinched components are briefly (up to 3 weeks) exposed to a salt spray environment. During this time, a small layer of corrosion products protrudes from the metal surface and fills the gaps between the joined sheets. Due to the increased contact area, the mechanical stress in the joint decreases, resulting in an improved fatigue performance. Although there are a variety of corrosion phenomena, for example, pitting, intergranular, and transgranular corrosion as well as galvanic corrosion, experimental studies indicate that galvanic corrosion is the main contributor of this effect. In the present work, a coupled electro‐chemo‐mechanical corrosion model is presented and applied to two test cases. Case I: corrosion products growth, and Case II: corrosion products growth and mechanical loading.}},
author = {{Harzheim, Sven and Chen, Chin and Hofmann, Martin and Wallmersperger, Thomas}},
issn = {{1617-7061}},
journal = {{PAMM}},
number = {{4}},
publisher = {{Wiley}},
title = {{{Coupled chemo‐electro‐mechanical model for galvanic corrosion in clinched components}}},
doi = {{10.1002/pamm.202400028}},
volume = {{24}},
year = {{2024}},
}
@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}},
}
@article{60300,
abstract = {{This study focuses on the phenomenological change in material strength caused by a specific heat treatment and the subsequent analysis of the influence on the clinching process and the resulting joint properties. For this purpose, three series of tests were performed. In the first series of tests, the influence of heat treatment up to 340 °C on the mechanical properties of an age-hardenable AlMgSi alloy was investigated. Holding time and temperature were varied and the material strength was evaluated by tensile and hardness tests. Two strength-increasing and two strength-reducing heat treatment parameters were identified. In the second series of tests, selected heat treatment parameters were applied to a larger number of specimens and the joint strength was investigated by shear and head tensile tests. In the shear tensile test, mainly the properties of the punch-side material have an influence on the resulting joint strength. A change in strength of the die-side material can be neglected. In contrast, the properties of both sheets are important in the head tensile test. The strength of the joint will only increase if the strength of both sheets is increased. In general, a strength increasing heat treatment resulted in higher joint strength. In the third series of tests, the factor of punch displacement was considered, which was demonstrated to directly influence the formation of the clinched joint geometry.}},
author = {{Steinfelder, Christian and Rempel, Dennis and Brosius, Alexander}},
issn = {{2666-3309}},
journal = {{Journal of Advanced Joining Processes}},
keywords = {{Joining by forming, Clinching, EN AW-6014, Heat treatment, Load-bearing capacity}},
publisher = {{Elsevier BV}},
title = {{{Influence of the material properties on the clinching process and the resulting load-bearing capacity of the joint}}},
doi = {{10.1016/j.jajp.2024.100263}},
volume = {{10}},
year = {{2024}},
}
@inproceedings{61797,
author = {{Hollmer, Katharina and Kuczyk, Martin and Friedlein, Johannes and Mergheim, Julia and Steinmann, Paul and Zimmermann, Martina}},
title = {{{Charakterisierung des Verformungszustandes gleichartiger Stahl-Stahl-Clinchverbindungen durch Anwendung quantitativer Bildanalyse }}},
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}},
}