@inproceedings{36473,
abstract = {{Destructive micrograph analysis (MA) is the standard method for the assessment of clinched joints. However, during the joint preparation for the MA, geometric features of the joint can change due to elastic effects and closing cracks. X-ray computed tomography (CT) is a promising alternative to investigate the joint non-destructively. However, if the
material properties of similar joining partners are the same, the CT is not able to correctly resolve surfaces in the joint that are close to or pressing onto each other. These surfaces are relevant for the determination of characteristic dimensions such as neck thickness and undercut. By placing a thin, highly radiopaque tin layer between the joining partners, the interfacial area in the reconstructed volume can be highlighted. In this work, a method for the localisation of the tin layer inside the joint as well as threshold value procedures for the outer joint contour in cross section images are investigated. The measured characteristic dimensions are compared with measured values from MA of the same samples and of samples without tin layer. In addition, possible effects of the tin layer on the joining point
characteristics as well as problems of the MA are discussed.}},
author = {{Busch, Matthias and Köhler, Daniel and Hausotte, Tino and Kupfer, Robert and Troschitz, Juliane and Gude, Maik }},
title = {{{Approach to Determine the Characteristic Dimensions of Clinched Joints by Industrial X-ray Computed Tomography}}},
year = {{2022}},
}
@article{29724,
abstract = {{ In many manufacturing areas, multi-material designs are implemented in which individual components are joined together to form complex structures with numerous joints. For example, in the automotive sector, cast components are used at the junctions of the body and joined with different types of sheet metal and extruded profiles. To be able to join structures consisting of different materials, alternative joining technologies have emerged in recent years. This includes clinching, which allows assembling of two or more thin sheet metal and casting parts by solely cold forming the material. Clinching the brittle and usually less ductile cast aluminium alloys remains a challenge because the brittle character of the cast aluminium alloys can cause cracks during the forming of the clinched joint. In this study, the influence of the heat treatment time of an aluminium casting alloy AlSi9 on the joinability in the clinching process is investigated. Specific heat treatment of the naturally hard AlSi9 leads to a modification of the eutectic microstructure, which can increase ductility. Based on this, it will be examined if specific clinching die geometries can be used, which achieve an optimized geometrical formation of the clinched joint. The load-bearing capacities of the clinched joints are determined and compared by shear tensile and head tensile tests. Furthermore, the joints are examined microscopically to investigate the influence of the heat treatment on the failure behaviour during the load-bearing tests as well as crack initiation within the joining process. }},
author = {{Neuser, Moritz and Böhnke, Max and Grydin, Olexandr and Bobbert, Mathias and Schaper, Mirko and Meschut, Gerson}},
issn = {{1464-4207}},
journal = {{Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications}},
keywords = {{Mechanical Engineering, General Materials Science}},
publisher = {{SAGE Publications}},
title = {{{Influence of heat treatment on the suitability for clinching of the aluminium casting alloy AlSi9}}},
doi = {{10.1177/14644207221075838}},
year = {{2022}},
}
@article{29505,
abstract = {{In modern vehicle chassis, multi-material design is implemented to apply the appropriate material for each functionality. In spaceframe technology, both sheet metal and continuous cast are joined to castings at the nodal points of the chassis. Since resistance spot welding is not an option when different materials are joined, research is focusing on mechanical joining methods for multi-material designs. To reduce weight and achieve the required strength, hardenable cast aluminium alloys of the AlSi-system are widely used. Thus, 85–90% of aluminium castings in the automotive industry are comprised of the AlSi-system. Due to the limited weldability, mechanical joining is a suitable process. For this application, various optimisation strategies are required to produce a crack-free joint, as the brittle character of the AlSi alloy poses a challenge. Thus, adapted castings with appropriate ductility are needed. Hence, in this study, the age-hardenable cast aluminium alloy AlSi10Mg is investigated regarding the correlation of the different thicknesses, the microstructural characteristics as well as the resulting mechanical properties. A variation of the thicknesses leads to different solidification rates, which in turn affect the microstructure formation and are decisive for the mechanical properties of the casting as well as the joinability. For the investigation, plates with thicknesses from 2.0 to 4.0 mm, each differing by 0.5 mm, are produced via sand casting. Hence, the overall aim is to evaluate the joinability of AlSi10Mg and derive conclusions concerning the microstructure and mechanical properties.}},
author = {{Neuser, Moritz and Grydin, Olexandr and Frolov, Y. and Schaper, Mirko}},
issn = {{0944-6524}},
journal = {{Production Engineering}},
keywords = {{Industrial and Manufacturing Engineering, Mechanical Engineering}},
publisher = {{Springer Science and Business Media LLC}},
title = {{{Influence of solidification rates and heat treatment on the mechanical performance and joinability of the cast aluminium alloy AlSi10Mg}}},
doi = {{10.1007/s11740-022-01106-1}},
year = {{2022}},
}
@article{31828,
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 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}},
}
@inbook{29771,
author = {{Grydin, Olexandr and Mortensen, Dag and Neuser, Moritz and Lindholm, Dag and Fjaer, Hallvard G. and Schaper, Mirko}},
booktitle = {{Light Metals 2022}},
isbn = {{9783030925284}},
issn = {{2367-1181}},
publisher = {{Springer International Publishing}},
title = {{{Numerical and Experimental Investigation of Heat Transfer in the Solidification-Deformation Zone During Twin-Roll Casting of Aluminum Strips}}},
doi = {{10.1007/978-3-030-92529-1_96}},
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}},
}
@article{34264,
abstract = {{In industrial x-ray computed tomography (CT), the application of more complex scan paths in comparison to the typical circular trajectory (${360}^{\circ}$ rotation of the measurement object) can extend the potential of CT. One way to enable such 3D scan trajectories is to use a 6-degrees-of-freedom (DOF) object manipulator system. In our case, a hexapod is mounted on top of the rotary table of a commercial CT scanner. This allows for adaptive tilting of the measurement object during the scan. For high accuracy, the geometry calibration of such setups is typically done using the x-ray projections of a calibrated multi-sphere object. Contrary to this, here, we demonstrate a procedure that is based on only a single sphere and can therefore experimentally be implemented with low effort. Using the intrinsic geometry parameters of the CT device as prior information, the hexapod coordinate system with respect to the CT machine coordinate system is determined by means of a one-step optimization approach. The resulting parameters are used to calculate projection matrices that enable the volume reconstruction for 3D scan trajectories. The method is validated using simulated x-ray images and experimental investigations including dimensional measurements. For the used setup, geometric measurement results for 3D scan trajectories that are calibrated with the presented method show in sum increased errors compared to the circular scans. A limited pose accuracy of the manipulator system is discussed as a potential cause. The results nevertheless indicate that the presented method is generally feasible for dimensional CT measurements provided that the pose accuracy is sufficient. The calibration procedure can therefore be a low-cost and easier to implement alternative compared to trajectory calibration methods based on multi-sphere objects, but with a tendency towards lower measurement accuracy. The methodology can in principle be transferred to different setups with 6-DOF manipulator systems, e.g. C-arm CT devices with a robot arm.}},
author = {{Butzhammer, Lorenz and Müller, Andreas Michael and Hausotte, Tino}},
issn = {{0957-0233}},
journal = {{Measurement Science and Technology}},
keywords = {{Applied Mathematics, Instrumentation, Engineering (miscellaneous)}},
number = {{1}},
publisher = {{IOP Publishing}},
title = {{{Calibration of 3D scan trajectories for an industrial computed tomography setup with 6-DOF object manipulator system using a single sphere}}},
doi = {{10.1088/1361-6501/ac9856}},
volume = {{34}},
year = {{2022}},
}
@article{33002,
abstract = {{Many mechanical material properties show a dependence on the strain rate, e.g. yield stress or elongation at fracture. The quantitative description of the material behavior under dynamic loading is of major importance for the evaluation of crash safety. This is carried out using numerical methods and requires characteristic values for the materials used. For the standardized determination of dynamic characteristic values in sheet metal materials, tensile tests performed according to the guideline from [1]. A particular challenge in dynamic tensile tests is the force measurement during the test. For this purpose, strain gauges are attached on each specimen, wired to the measuring equipment and calibrated. This is a common way to determine a force signal that is as low in vibration and as free of bending moments as possible. The preparation effort for the used strain gauges are enormous. For these reasons, an optical method to determine the force by strain measurement using DIC is presented. The experiments are carried out on a high speed tensile testing system. In combioantion with a 3D DIC high speed system for optical strain measurement. The elastic deformation of the specimen in the dynamometric section is measured using strain gauges and the optical method. The measured signals are then compared to validate the presented method. The investigations are conducted using the dual phase steel material HCT590X and the aluminum material EN AW-6014 T4. Strain rates of up to 240 s-1 are investigated.}},
author = {{Böhnke, Max and Unruh, Eduard and Sell, Stanislaw and Bobbert, Mathias and Hein, David and Meschut, Gerson}},
issn = {{1662-9795}},
journal = {{Key Engineering Materials}},
keywords = {{Mechanical Engineering, Mechanics of Materials, General Materials Science}},
location = {{Braga, Portugal}},
pages = {{1564--1572}},
publisher = {{Trans Tech Publications, Ltd.}},
title = {{{Functionality Study of an Optical Measurement Concept for Local Force Signal Determination in High Strain Rate Tensile Tests}}},
doi = {{10.4028/p-wpuzyw}},
volume = {{926}},
year = {{2022}},
}
@inbook{33003,
author = {{Böhnke, Max and Bielak, Christian Roman and Bobbert, Mathias and Meschut, Gerson}},
booktitle = {{The Minerals, Metals & Materials Series}},
isbn = {{9783031062117}},
issn = {{2367-1181}},
location = {{Toronto, Kanada}},
publisher = {{Springer International Publishing}},
title = {{{Development of a Modified Punch Test for Investigating the Failure Behavior in Sheet Metal Materials}}},
doi = {{10.1007/978-3-031-06212-4_52}},
year = {{2022}},
}
@article{34572,
author = {{Böhnke, Max and Bielak, Christian Roman and Bobbert, Mathias and Meschut, Gerson}},
journal = {{Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications}},
publisher = {{SAGE Journals}},
title = {{{Experimental and numerical investigation of the influence of multiaxial loading conditions on the failure behavior of clinched joints}}},
doi = {{10.1177/14644207221145886}},
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}},
}
@article{34216,
abstract = {{Mechanical joining technologies are increasingly used in multi-material lightweight constructions and offer opportunities to create versatile joining processes due to their low heat input, robustness to metallurgical incompatibilities and various process variants. They can be categorised into technologies which require an auxiliary joining element, or do not require an auxiliary joining element. A typical example for a mechanical joining process with auxiliary joining element is self-piercing riveting. A wide range of processes exist which are not requiring an auxiliary joining element. This allows both point-shaped (e.g., by clinching) and line-shaped (e.g., friction stir welding) joints to be produced. In order to achieve versatile processes, challenges exist in particular in the creation of intervention possibilities in the process and the understanding and handling of materials that are difficult to join, such as fiber reinforced plastics (FRP) or high-strength metals. In addition, predictive capability is required, which in particular requires accurate process simulation. Finally, the processes must be measured non-destructively in order to generate control variables in the process or to investigate the cause-effect relationship. This paper covers the state of the art in scientific research concerning mechanical joining and discusses future challenges on the way to versatile mechanical joining processes.}},
author = {{Meschut, Gerson and Merklein, M. and Brosius, A. and Drummer, D. and Fratini, L. and Füssel, U. and Gude, M. and Homberg, Werner and Martins, P.A.F. and Bobbert, Mathias and Lechner, M. and Kupfer, R. and Gröger, B. and Han, Daxin and Kalich, J. and Kappe, Fabian and Kleffel, T. and Köhler, D. and Kuball, C.-M. and Popp, J. and Römisch, D. and Troschitz, J. and Wischer, Christian and Wituschek, S. and Wolf, M.}},
issn = {{2666-3309}},
journal = {{Journal of Advanced Joining Processes}},
keywords = {{Mechanical Engineering, Mechanics of Materials, Engineering (miscellaneous), Chemical Engineering (miscellaneous)}},
publisher = {{Elsevier BV}},
title = {{{Review on mechanical joining by plastic deformation}}},
doi = {{10.1016/j.jajp.2022.100113}},
volume = {{5}},
year = {{2022}},
}
@article{34243,
abstract = {{ In view of economic and ecological trends, the concepts for lightweight construction in transport systems are becoming increasingly important. These are frequently applied in the form of multi-material systems, which are characterized by the selective use of materials and geometries. One major challenge in the manufacturing of multi-material systems is the joining of the individual components to form a complete system. Mechanical joining processes such as semi-tubular self-piercing riveting are frequently used for this application but reach their limits concerning the number of combinations of geometry and material. In order to react to the requirements and to increase the versatility of semi-tubular self-pierce riveting, a process combination consisting of a tumbling process and a self-pierce riveting process has been presented previously. This process combination is used in this work to investigate the versatility and to identify the influencing parameters on it. For this purpose, experiments are conducted to identify process-side influence possibilities. The tests are performed with a dual-phase steel aluminum alloy to represent the varying mechanical characteristics of multi-material systems. Furthermore, the initial sheet thicknesses of the joining partners are varied in several steps. In addition to the geometric joint formation used to describe the undercut, the rivet head end position and the residual sheet thickness, the joining process, is also analyzed during the investigations. Further, the innovative joining process is evaluated by comparing it with a conventional self-piercing riveting process. The knowledge obtained represents a basis for the identification and evaluation of the versatility of the process combination. }},
author = {{Wituschek, Simon and Kappe, Fabian and Meschut, Gerson and Lechner, Michael}},
issn = {{1464-4207}},
journal = {{Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications}},
keywords = {{Mechanical Engineering, General Materials Science}},
publisher = {{SAGE Publications}},
title = {{{Geometric and mechanical joint characterization of conventionally and tumbled self-piercing riveting joints}}},
doi = {{10.1177/14644207221135400}},
year = {{2022}},
}
@article{34242,
author = {{Neuser, Moritz and Kappe, Fabian and Ostermeier, Jakob and Krüger, Jan Tobias and Bobbert, Mathias and Meschut, Gerson and Schaper, Mirko and Grydin, Olexandr}},
issn = {{1438-1656}},
journal = {{Advanced Engineering Materials}},
keywords = {{Condensed Matter Physics, General Materials Science}},
number = {{10}},
publisher = {{Wiley}},
title = {{{Mechanical Properties and Joinability of AlSi9 Alloy Manufactured by Twin‐Roll Casting}}},
doi = {{10.1002/adem.202200874}},
volume = {{24}},
year = {{2022}},
}
@article{31360,
abstract = {{The adaptive joining process employing friction-spun joint connectors (FSJC) is a promising method for the realization of adaptable joints and thus for lightweight construction. In addition to experimental investigations, numerical studies are indispensable tools for its development. Therefore, this paper includes an analysis of boundary conditions for the spatial discretization and mesh modeling techniques, the material modeling, the contact and friction modeling, and the thermal boundary conditions for the finite element (FE) modeling of this joining process. For these investigations, two FE models corresponding to the two process steps were set up and compared with the two related processes of friction stir welding and friction drilling. Regarding the spatial discretization, the Lagrangian approach is not sufficient to represent the deformation that occurs. The Johnson-Cook model is well suited as a material model. The modeling of the contact detection and friction are important research subjects. Coulomb’s law of friction is not adequate to account for the complex friction phenomena of the adaptive joining process. The thermal boundary conditions play a decisive role in heat generation and thus in the material flow of the process. It is advisable to use temperature-dependent parameters and to investigate in detail the influence of radiation in the entire process.}},
author = {{Oesterwinter, Annika and Wischer, Christian and Homberg, Werner}},
issn = {{2075-4701}},
journal = {{Metals}},
keywords = {{General Materials Science, Metals and Alloys}},
number = {{5}},
publisher = {{MDPI AG}},
title = {{{Identification of Requirements for FE Modeling of an Adaptive Joining Technology Employing Friction-Spun Joint Connectors (FSJC)}}},
doi = {{10.3390/met12050869}},
volume = {{12}},
year = {{2022}},
}
@article{34224,
abstract = {{Crack growth in structures depends on the cyclic loads applied on it, such as mechanical, thermal and contact, as well as residual stresses, etc. To provide an accurate simulation of crack growth in structures, it is of high importance to integrate all kinds of loading situations in the simulations. Adapcrack3D is a simulation program that can accurately predict the propagation of cracks in real structures. However, until now, this three-dimensional program has only considered mechanical loads and static thermal loads. Therefore, the features of Adapcrack3D have been extended by including contact loading in crack growth simulations. The numerical simulation of crack propagation with Adapcrack3D is generally carried out using FE models of structures provided by the user. For simulating models with contact loading situations, Adapcrack3D has been updated to work with FE models containing multiple parts and necessary features such as coupling and surface interactions. Because Adapcrack3D uses the submodel technique for fracture mechanical evaluations, the architecture of the submodel is also modified to simulate models with contact definitions between the crack surfaces. This paper discusses the newly implemented attribute of the program with the help of illustrative examples. The results confirm that the contact simulation in Adapcrack3D is a major step in improving the functionality of the program.}},
author = {{Joy, Tintu David and Weiß, Deborah and Schramm, Britta and Kullmer, Gunter}},
issn = {{2076-3417}},
journal = {{Applied Sciences}},
keywords = {{Fluid Flow and Transfer Processes, Computer Science Applications, Process Chemistry and Technology, General Engineering, Instrumentation, General Materials Science}},
number = {{15}},
publisher = {{MDPI AG}},
title = {{{Further Development of 3D Crack Growth Simulation Program to Include Contact Loading Situations}}},
doi = {{10.3390/app12157557}},
volume = {{12}},
year = {{2022}},
}
@inproceedings{30726,
author = {{Weiß, Deborah and Schramm, Britta and Kullmer, Gunter}},
booktitle = {{Procedia Structural Integrity}},
issn = {{2452-3216}},
keywords = {{General Engineering, Energy Engineering and Power Technology}},
location = {{online}},
pages = {{139--147}},
publisher = {{Elsevier BV}},
title = {{{Influence of plane mixed-mode loading on the kinking angle of clinchable metal sheets}}},
doi = {{10.1016/j.prostr.2022.03.082}},
volume = {{39}},
year = {{2022}},
}
@article{34070,
author = {{Schramm, Britta and Harzheim, Sven and Weiß, Deborah and Joy, Tintu David and Hofmann, Martin and Mergheim, Julia 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 = {{{A Review on the Modeling of the Clinching Process Chain - Part III: Operational Phase}}},
doi = {{10.1016/j.jajp.2022.100135}},
year = {{2022}},
}
@article{34246,
author = {{Kullmer, Gunter and Weiß, Deborah and Schramm, Britta}},
issn = {{0013-7944}},
journal = {{Engineering Fracture Mechanics}},
keywords = {{Mechanical Engineering, Mechanics of Materials, General Materials Science}},
publisher = {{Elsevier BV}},
title = {{{Development of a method for the separate measurement of the growth of internal crack tips by means of the potential drop method}}},
doi = {{10.1016/j.engfracmech.2022.108899}},
year = {{2022}},
}
@article{34241,
abstract = {{Due to the increasing use of multi-material constructions and the resulting material incompatibilities, mechanical joining technologies are gaining in importance. The reasons for this are the variety of joining possibilities as well as high load-bearing capacities. However, the currently rigid tooling systems cannot react to changing boundary conditions, such as changed sheet thicknesses or strength. For this reason, a large number of specialised joining processes have been developed to expand the range of applications. Using a versatile self-piercing riveting process, multi-material structures are joined in this paper. In this process, a modified tool actuator technology is combined with multi-range capable auxiliary joining parts. The multi-range capability of the rivets is achieved by forming the rivet head onto the respective thickness of the joining part combination without creating a tooling set-up effort. The joints are investigated both experimentally on the basis of joint formation and load-bearing capacity tests as well as by means of numerical simulation. It turned out that all the joints examined could be manufactured according to the defined standards. The load-bearing capacities of the joints are comparable to those of conventionally joined joints. In some cases the joint fails prematurely, which is why lower energy absorptions are obtained. However, the maximum forces achieved are higher than those of conventional joints. Especially in the case of high-strength materials arranged on the die side, the interlock formation is low. In addition, the use of die-sided sheets requires a large deformation of the rivet head protrusion, which leads to an increase in stress and, as a result, to damage if the rivet head. However, a negative influence on the joint load-bearing capacity could be excluded.}},
author = {{Kappe, Fabian and Wituschek, Simon and Bobbert, Mathias and Lechner, Michael and Meschut, Gerson}},
issn = {{0944-6524}},
journal = {{Production Engineering}},
keywords = {{Industrial and Manufacturing Engineering, Mechanical Engineering}},
publisher = {{Springer Science and Business Media LLC}},
title = {{{Joining of multi-material structures using a versatile self-piercing riveting process}}},
doi = {{10.1007/s11740-022-01151-w}},
year = {{2022}},
}