@inproceedings{36839,
  author       = {{Neumann, Stefan and Meschut, Gerson and Otroshi, Mortaza and Kneuper, Florian and Schulze, Andre and Tekkaya, Erman}},
  title        = {{{Mechanically Joined Extrusion Profiles for Battery Trays}}},
  year         = {{2023}},
}

@article{27186,
  abstract     = {{The presented paper aims to characterize the damage and fracture behavior of HX340LAD Micro-Alloyed steels using small punch test. Variations with respect to punch geometries and cutting clearance are made to describe the damage behavior of the material under different loading conditions. Experimental investigations are conducted to identify the crack initiation in the specimens. Furthermore, the numerical FEM simulations are performed to identify the stress state at crack initiation. It is shown that different stress states from shear to biaxial tension can be achieved by changing the geometries of punch and varying the cutting clearance. Moreover, it is presented how changing the configurations can influence the stress state variables: Triaxiality and lode angle parameter.}},
  author       = {{Otroshi, Mortaza and Meschut, Gerson}},
  issn         = {{1350-6307}},
  journal      = {{Engineering Failure Analysis}},
  keywords     = {{Ductile damage, stress state, small punch test, triaxiality, lode angle parameter}},
  number       = {{c}},
  publisher    = {{Elsevier}},
  title        = {{{Influence of cutting clearance and punch geometry on the stress state in small punch test }}},
  doi          = {{10.1016/j.engfailanal.2022.106183}},
  volume       = {{136}},
  year         = {{2022}},
}

@inproceedings{34152,
  author       = {{Otroshi, Mortaza and Meschut, Gerson}},
  location     = {{Rostock}},
  publisher    = {{Europäische Forschungsgesellschaft für Blechverarbeitung e.V. }},
  title        = {{{Methodenentwicklung zur Verbesserung der Schädigungsmodellierung in der numerischen 3D-Belastungssimulation mechanischer Fügeverfahren unter Berücksichtigung der fügeinduzierten Vorbeanspruchung}}},
  year         = {{2022}},
}

@inproceedings{34153,
  author       = {{Otroshi, Mortaza and Meschut, Gerson}},
  publisher    = {{Europäische Forschungsgesellschaft für Blechverarbeitung e.V.}},
  title        = {{{Schädigungsmodellierung von Hilfsfügeelementen beim mechanischen Fügen von Stahlwerkstoffen}}},
  year         = {{2022}},
}

@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}},
}

@phdthesis{33499,
  author       = {{Otroshi, Mortaza}},
  isbn         = {{978-3-8440-8777-2}},
  issn         = {{1434-6915}},
  pages        = {{128}},
  publisher    = {{Shaker Verlag}},
  title        = {{{Damage modeling in the numerical simulation of mechanical joining processes}}},
  doi          = {{https://doi.org/10.2370/9783844087772}},
  year         = {{2022}},
}

@inproceedings{30123,
  author       = {{Otroshi, Mortaza and Meschut, Gerson}},
  location     = {{Pittsburg, Pennsylvania, USA}},
  title        = {{{Investigation of the three-dimensional stress state during loading of self-piercing riveted joints}}},
  year         = {{2022}},
}

@inproceedings{36838,
  author       = {{Neumann, Stefan and Meschut, Gerson and Otroshi, Mortaza and Kneuper, Florian and Schulze, Andre and Tekkaya, Erman}},
  title        = {{{MECHANICALLY JOINED EXTRUSION PROFILES FOR BATTERY TRAYS}}},
  year         = {{2022}},
}

@article{30963,
  abstract     = {{<jats:title>Abstract</jats:title><jats:p>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.</jats:p>}},
  author       = {{Ewenz, Lars and Bielak, Christian Roman and Otroshi, Mortaza and Bobbert, Mathias and Meschut, Gerson and Zimmermann, Martina}},
  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{21280,
  author       = {{Masendorf, Lukas and Wächter, Michael and Esderts, Alfons and Otroshi, Mortaza and Meschut, Gerson}},
  title        = {{{Simulationsbasierte Lebensdauerabschätzung einer stanzgenieteten Fügeverbindung unter zyklischer Belastung}}},
  year         = {{2021}},
}

@article{25476,
  abstract     = {{This study deals with the damage behavior of metallic materials by the application of different manufacturing processes and using different optical measurement methods to identify the crack initiation in the damage specimen. The study is intended to highlight the importance of considering manufacturing processes and optical measurement methods in a numerical simulation when analyzing the damage behavior of metallic materials. To describe the damage behavior of the material in the process chain simulations, it is important to calibrate the parameters of damage model more accurately. These parameters are determined using experimental investigation of desired damage specimens. In this regard, a selected damage specimen manufactured by different cutting processes is first experimentally and then numerically investigated. It is shown that the manufacturing process and the optical measurement methods influence the stress state analyzed in the numerical simulation.}},
  author       = {{Otroshi, Mortaza and Meschut, Gerson and Nesakumar, Aathavan}},
  journal      = {{Journal of Manufacturing Engineering}},
  keywords     = {{Damage behaviour, Stress triaxiality, Manufacturing process and Optical measurement}},
  number       = {{3}},
  pages        = {{70--76}},
  title        = {{{The influence of manufacturing processes and optical measurement methods on the damage behavior of HX340LAD micro-alloyed steels}}},
  doi          = {{https://doi.org/10.37255/jme.v16i3pp070-076}},
  volume       = {{16}},
  year         = {{2021}},
}

@article{21810,
  author       = {{Otroshi, Mortaza and Meschut, Gerson and Bielak, Christian Roman and Masendorf, Lukas and Esderts, Alfons}},
  issn         = {{1662-9795}},
  journal      = {{Key Engineering Materials}},
  pages        = {{35--40}},
  publisher    = {{Trans Tech Publications Ltd}},
  title        = {{{Modeling of Stiffness Anisotropy in Simulation of Self-Piercing Riveted Components}}},
  doi          = {{https://doi.org/10.4028/www.scientific.net/KEM.883.35}},
  volume       = {{883}},
  year         = {{2021}},
}

@article{21545,
  author       = {{Masendorf, Lukas and Wächter, Michael and Esderts, Alfons and Otroshi, Mortaza and Meschut, Gerson}},
  issn         = {{8756-758X}},
  journal      = {{Fatigue & Fracture of Engineering Materials & Structures}},
  pages        = {{15}},
  title        = {{{Service life estimation of self‐piercing riveted joints by linear damage accumulation}}},
  doi          = {{10.1111/ffe.13446}},
  year         = {{2021}},
}

@techreport{20145,
  abstract     = {{Der Karosseriebau ist zunehmend durch die Verwendung unterschiedlicher Werkstoffe in Mischbauweise gekennzeichnet, was zu einem Einsatz von mechanischen Fügeverfahren geführt hat. Hieraus resultieren die Zielsetzungen, die mechanischen Fügeverfahren in ihrer Effizienz und ihren Einsatzbereichen zu erweitern, sowie die Anzahl der Experimente zu reduzieren und Entwicklungszyklen zu verkürzen. Dies erfolgt mit Unterstützung der numerischen Simulation. Neben der Beschreibung des plastischen Verhaltens gilt es auch, das Schädigungsverhalten abzubilden.

Der Fügeprozess bzw. die Fügerichtung erfolgt senkrecht zur Blechoberfläche und führt somit zu einem dreidimensionalen Zustand der Fügelemente. Hieraus leitet sich die Herausforderung ab, das Werkstoffversagen in Abhängigkeit der Beanspruchungssituation zu beschreiben. Ein einfacher Ansatz zur Abbildung des Durchdringens ist ein geometrisches Trennkriterium.

Ein solches Kriterium basiert i.d.R. auf einem experimentell beobachteten Verhalten und ist somit nicht prognosefähig für Variationen bzgl. Werkzeugkonfigurationen, Blechdicken- und Werkstoffgüten-Kombinationen. In diesem Projekt wird das Schädigungsmodell GISSMO (Generalized Incremental Stress State dependent damage Model) verwendet, um die Entwicklung der duktilen Schädigung zu beschreiben und den Bruchbeginn während des Stanzniet- und Schneidclinchens vorherzusagen.

Der Spannungszustand während der Prozesssimulation wird untersucht und die verschiedenen Schädigungsproben werden experimentell erprobt, um die Versagenskurven zu charakterisieren. Die Versagenskurven werden im Schädigungsmodell GISSMO definiert. Um die Genauigkeit des Modells zu gewährleisten, wird die Verifizierung des Modells durch die Simulation von Schädigungsproben mit dem Schädigungsmodell durchgeführt.

Zur Validierung des Modells wird die Simulation des Fügeprozesses mit dem Schädigungsmodell durchgeführt und die Ergebnisse von Simulation und Experiment verglichen. Darüber hinaus werden Sensitivitätsanalysen durchgeführt, um die Einflüsse der Fertigungsprozesse, der Lackierung und des Diskretisierungsgrades auf das Schädigungsverhalten des Materials zu identifizieren.
Das IGF-Vorhaben „Methodenentwicklung zur Schädigungsmodellierung für die numerische Prozesssimulation mechanischer Fügeverfahren" der Forschungsvereinigung EFB e.V. wurde unter der Fördernummer AiF 19452N über die Arbeitsgemeinschaft industrieller Forschungsvereinigungen (AiF) im Rahmen des Programms zur Förderung der Industriellen Gemeinschaftsforschung (IGF) vom Bundesministerium für Wirtschaft und Energie aufgrund eines Beschlusses des Deutschen Bundestages gefördert. Der Abschlussbericht ist als EFB-Forschungsbericht Nr. 527 erschienen und bei der EFB-Geschäftsstelle und im Buchhandel erhältlich.}},
  author       = {{Otroshi, Mortaza and Meschut, Gerson}},
  isbn         = {{978-3-86776-582-4}},
  pages        = {{182}},
  publisher    = {{Europäische Forschungsgesellschaft für Blechverarbeitung e.V.}},
  title        = {{{Methodenentwicklung zur Schädigungsmodellierung für die numerische Prozesssimulation mechanischer Fügeverfahren}}},
  year         = {{2020}},
}

@inproceedings{20146,
  abstract     = {{Joining technology is regarded as a key technology for reducing energy consumption and CO2 imitation as well as the use of innovative materials and development of new, resource-saving products. Punch riveting is a widely used and established joining process in many sectors. The white and brown goods, electrical engineering, construction and, in particular, the automotive industry are some of the sectors mentioned here.

Since the design and assessment of punch rivet components with regard to structural durability can only be carried out experimentally using prototypes due to a lack of experience and calculation concepts, the improvement of this uneconomical and time-consuming procedure is the goal of this contribution.

Therefore, a numerical simulation and design method for cyclically loads punched riveted joints shall be introduced. This concept shall be based on the notch strain concept.

The following steps are necessary to achieve the goal shown above:

    Tensile tests on all materials involved in the joint for determination of tensile strength and quasi-static stress-strain curves
    Estimation of the cyclic material properties from the tensile strength in order to obtain the strain-life curve and the cyclic stress-strain curve
    Estimation of mean stress sensitivity from the tensile strength to conduct an amplitude transformation for variable amplitude loadings.
    Execution of a 2D forming simulation of the joining process to determine the geometry and the stresses and degrees of deformation present in the connection
    Transferring the results of the forming simulation into a static-mechanical load simulation for determining the relation between the external load and the elastic-plastic strain at the critical point
    Estimation of the service life by means of the damage parameter Wöhler curves calculated from the strain-life curve

In order to verify the simulation and calculation method, service life investigations have been carried out on punched riveted components under constant and variable amplitude load.

The test results, as well as the workflow through the fatigue assessment and its accuracy in estimation the fatigue life will be shown in this contribution.}},
  author       = {{Masendorf, Lukas and Wächter, Michael and Horstmann, Stephan and Otroshi, Mortaza and Esderts, Alfons and Meschut, Gerson}},
  isbn         = {{978-3-9820591-0-5}},
  keywords     = {{punch rivet, notch strain conept, structural durability}},
  location     = {{Darmstadt, Germany}},
  publisher    = {{Deutscher Verband für Materialforschung und -prüfung e.V.}},
  title        = {{{Linear damage accumulation of self-pierce riveted joints}}},
  year         = {{2020}},
}

@article{20170,
  author       = {{Otroshi, Mortaza and Meschut, Gerson}},
  issn         = {{0300-3167}},
  journal      = {{Umformtechnik Blech Rohre Profile}},
  number       = {{7/20}},
  pages        = {{48--50}},
  title        = {{{Spannungszustandsabhängige Schädigungsmodellierung zum Halbhohlstanznieten}}},
  year         = {{2020}},
}

@techreport{21152,
  abstract     = {{In modern lightweight designs, it is important to find a compromise between the strength and the weight of the construction detail. Hence, hybrid structures made of aluminum and steel materials are increasingly being used in automotive applications. Due to limitations in the quality of resistance spot welding, self-piercing riveting can be used as an alternative process to join sheets from different material groups. The aim of this project is to develop a computational method to assess the self-piercing riveted components subjected to the cyclic loads. To achieve this goal, two approaches are followed: Evaluation unsing internal forces: A substitute model is developed to describe the stiffness of self-piercing riveted joints subjected to different loading conditions. The parameters of the substitute model are identified and the internal force components acting on the joint are evaluated. The model provides the basis for the subsequent fatigue life estimation of self-piercing riveted components. For joints subjected to low bending moments, the fatigue life of components can be estimated accurately. Due to lack of specimen geometries producing pure bending and the combination of tension-bending forces, it is not possible to estimate the fatigue life of complex components subjected to high bending moments. Based on the results of [Mesc 16], the methodology is further developed to determine the stresses acting on the joint and to characterize the joining point with the use of simulations. The local concept proposed in the FKM guideline nonlinear provides the basis for the analytical assessment of self-piercing riveted components. In this regard, the cyclic behavior of the material and the local stresses are required as input data. The cyclic behavior of the aluminum EN AW-6181A-T6 and steel HX340LAD sheets were already determined in the previous project. Subsequently, in this project the properties of the rivet made of 38B2 steel are identified. The finite element analysis using elastic-plastic material behavior is used to determine the stresses in the joint subjected to the cyclic loads. To verify the model, the results of simulations and experiments are compared concerning the crack initiation zone as well as the determined number of cycles. To determine the stresses that can be used for the analytical assessment, the damage relevant load components need to be identified. In this regard, it is recommended to use the normal stress perpendicular to the crack propagation direction, the stress of crack opening mode I. Using the damage parameter PRAM and considering the support factors according to the FKM guideline nonlinear, a reliable estimation of the crack initiation zone within the joint is possible. Regarding the joint made of aluminum sheet EN AW-6181A, the methodology is able to provide promising results. However, regarding the joints made of aluminum EN AW-6181A and steel HX340LAD sheets, there is still potential to improve the results. The reasons for this are described in chapter 7.2.5 and 7.2.6. An analytical fatigue assessment is relatively easy to achieve with procedure 1. However, contrary to the objective formulated above, expensive fatigue tests are necessary to determine the failure conditions (strength values). This disadvantage can be circumvented by determining the strength information of individual joining points under different load types using procedure 2. The latter, in return, is not suitable for the assessment of complex components with several joining points. Due to the increasing calculation times of the simulation, the application in this case is not economically reasonable. By the described combination of method 1 and 2, the disadvantages of the two individual concepts can be compensated. An analytical fatigue assessment of self-piercing riveted components can be carried out based on the cyclic material behavior. The objective of the project was achieved.}},
  author       = {{Otroshi, Mortaza and Meschut, Gerson and Masendorf, Lukas and Esderts, Alfons}},
  isbn         = {{978-3-86776-602-9}},
  pages        = {{282}},
  publisher    = {{Europäische Forschungsgesellschaft für Blechverarbeitung e.V. (EFB)}},
  title        = {{{Simulationsbasierte Betriebsfestigkeitsanalyse stanzgenieteter Bauteile}}},
  year         = {{2020}},
}

@inproceedings{20567,
  author       = {{Otroshi, Mortaza and Meschut, Gerson and Masendorf, Lukas and Esderts, Alfons}},
  location     = {{Rostock, Germany}},
  title        = {{{Simulationsbasierte Betriebsfestigkeitsanalyse stanzgenieteter Bauteile}}},
  year         = {{2020}},
}

@article{20143,
  author       = {{Otroshi, Mortaza and Rossel, Moritz and Meschut, Gerson}},
  journal      = {{Journal of Advanced Joining Processes}},
  keywords     = {{Self-pierce riveting, Ductile fracture, Damage modeling, GISSMO damage model}},
  publisher    = {{Elsevier}},
  title        = {{{Stress state dependent damage modeling of self-pierce riveting process simulation using GISSMO damage model}}},
  doi          = {{10.1016/j.jajp.2020.100015}},
  volume       = {{1}},
  year         = {{2020}},
}

@inproceedings{20147,
  author       = {{Otroshi, Mortaza and Meschut, Gerson and Masendorf, Lukas and Esderts, Alfons}},
  isbn         = {{978-3-86776-580-0}},
  location     = {{Braunschweig, Germany}},
  pages        = {{75--80}},
  publisher    = {{Europäische Forschungsgesellschaft für Blechverarbeitung e.V.}},
  title        = {{{Simulationsbasierte Betriebsfestigkeitsanalyse stanzgenieteter Bauteile}}},
  year         = {{2019}},
}