[{"intvolume":"       196","citation":{"bibtex":"@article{Friedlein_Mergheim_Steinmann_2025, title={Modelling of stress-state-dependent ductile damage with gradient-enhancement exemplified for clinch joining}, volume={196}, DOI={<a href=\"https://doi.org/10.1016/j.jmps.2025.106026\">10.1016/j.jmps.2025.106026</a>}, number={106026}, journal={Journal of the Mechanics and Physics of Solids}, publisher={Elsevier BV}, author={Friedlein, Johannes and Mergheim, Julia and Steinmann, Paul}, year={2025} }","mla":"Friedlein, Johannes, et al. “Modelling of Stress-State-Dependent Ductile Damage with Gradient-Enhancement Exemplified for Clinch Joining.” <i>Journal of the Mechanics and Physics of Solids</i>, vol. 196, 106026, Elsevier BV, 2025, doi:<a href=\"https://doi.org/10.1016/j.jmps.2025.106026\">10.1016/j.jmps.2025.106026</a>.","short":"J. Friedlein, J. Mergheim, P. Steinmann, Journal of the Mechanics and Physics of Solids 196 (2025).","apa":"Friedlein, J., Mergheim, J., &#38; Steinmann, P. (2025). Modelling of stress-state-dependent ductile damage with gradient-enhancement exemplified for clinch joining. <i>Journal of the Mechanics and Physics of Solids</i>, <i>196</i>, Article 106026. <a href=\"https://doi.org/10.1016/j.jmps.2025.106026\">https://doi.org/10.1016/j.jmps.2025.106026</a>","ama":"Friedlein J, Mergheim J, Steinmann P. Modelling of stress-state-dependent ductile damage with gradient-enhancement exemplified for clinch joining. <i>Journal of the Mechanics and Physics of Solids</i>. 2025;196. doi:<a href=\"https://doi.org/10.1016/j.jmps.2025.106026\">10.1016/j.jmps.2025.106026</a>","ieee":"J. Friedlein, J. Mergheim, and P. Steinmann, “Modelling of stress-state-dependent ductile damage with gradient-enhancement exemplified for clinch joining,” <i>Journal of the Mechanics and Physics of Solids</i>, vol. 196, Art. no. 106026, 2025, doi: <a href=\"https://doi.org/10.1016/j.jmps.2025.106026\">10.1016/j.jmps.2025.106026</a>.","chicago":"Friedlein, Johannes, Julia Mergheim, and Paul Steinmann. “Modelling of Stress-State-Dependent Ductile Damage with Gradient-Enhancement Exemplified for Clinch Joining.” <i>Journal of the Mechanics and Physics of Solids</i> 196 (2025). <a href=\"https://doi.org/10.1016/j.jmps.2025.106026\">https://doi.org/10.1016/j.jmps.2025.106026</a>."},"publication_identifier":{"issn":["0022-5096"]},"publication_status":"published","doi":"10.1016/j.jmps.2025.106026","volume":196,"author":[{"full_name":"Friedlein, Johannes","last_name":"Friedlein","first_name":"Johannes"},{"full_name":"Mergheim, Julia","last_name":"Mergheim","first_name":"Julia"},{"full_name":"Steinmann, Paul","last_name":"Steinmann","first_name":"Paul"}],"date_updated":"2025-01-31T17:06:22Z","status":"public","type":"journal_article","article_type":"original","article_number":"106026","user_id":"84990","_id":"58492","project":[{"_id":"130","name":"TRR 285: TRR 285:  Methodenentwicklung zur mechanischen Fügbarkeit in wandlungsfähigen Prozessketten","grant_number":"418701707"},{"name":"TRR 285 - A: TRR 285 - Project Area A","_id":"131"},{"name":"TRR 285 – A05: TRR 285 - Subproject A05","_id":"139"}],"year":"2025","title":"Modelling of stress-state-dependent ductile damage with gradient-enhancement exemplified for clinch joining","date_created":"2025-01-31T17:04:12Z","publisher":"Elsevier BV","abstract":[{"text":"A coupled finite plasticity ductile damage and failure model is proposed for the finite element simulation of clinch joining, which incorporates stress-state dependency and regularisation by gradient-enhancement of the damage variable. Ductile damage is determined based on a failure indicator governed by a failure surface in stress space. The latter is exemplary chosen as a combination of the Hosford–Coulomb and Cockcroft–Latham–Oh failure criteria for the high and low stress triaxiality range, respectively, to cover the wide stress range encountered in forming. Damage is coupled to elasto-plasticity to capture the damage-induced degradation of the stiffness and flow stress. This affects the material behaviour up to failure, thereby realistically altering the stress state. Consequently, especially for highly ductile materials, where substantial necking and localisation precede material fracture, the failure prediction is enhanced. The resulting stress softening is regularised by gradient-enhancement to obtain mesh-objective results. The analysis of a modified punch test experiment emphasises how the damage-induced softening effect can strongly alter the actual stress state towards failure. Moreover, the impact of successful regularisation is shown, and the applicability of the damage and failure model to clinch joining is proven.","lang":"eng"}],"publication":"Journal of the Mechanics and Physics of Solids","language":[{"iso":"eng"}],"keyword":["Finite plasticity","Ductile damage","Gradient-enhancement","Stress-state dependency","Failure"]},{"publication":"Journal of Manufacturing and Materials Processing","abstract":[{"lang":"eng","text":"<jats:p>Similar to bulk metal forming, clinch joining is characterised by large plastic deformations and a variety of different 3D stress states, including severe compression. However, inherent to plastic forming is the nucleation and growth of defects, whose detrimental effects on the material behaviour can be described by continuum damage models and eventually lead to material failure. As the damage evolution strongly depends on the stress state, a stress-state-dependent model is utilised to correctly track the accumulation. To formulate and parameterise this model, besides classical experiments, so-called modified punch tests are also integrated herein to enhance the calibration of the failure model by capturing a larger range of stress states and metal-forming-specific loading conditions. Moreover, when highly ductile materials are considered, such as the dual-phase steel HCT590X and the aluminium alloy EN AW-6014 T4 investigated here, strong necking and localisation might occur prior to fracture. This can alter the stress state and affect the actual strain at failure. This influence is captured by coupling plasticity and damage to incorporate the damage-induced softening effect. Its relative importance is shown by conducting inverse parameter identifications to determine damage and failure parameters for both mentioned ductile metals based on up to 12 different experiments.</jats:p>"}],"keyword":["ductile damage","stress-state dependency","failure","parameter identification","punch test","clinching"],"language":[{"iso":"eng"}],"issue":"4","year":"2024","publisher":"MDPI AG","date_created":"2025-01-31T16:59:13Z","title":"Material Parameter Identification for a Stress-State-Dependent Ductile Damage and Failure Model Applied to Clinch Joining","type":"journal_article","status":"public","project":[{"grant_number":"418701707","name":"TRR 285: TRR 285:  Methodenentwicklung zur mechanischen Fügbarkeit in wandlungsfähigen Prozessketten","_id":"130"},{"name":"TRR 285 - A: TRR 285 - Project Area A","_id":"131"},{"_id":"139","name":"TRR 285 – A05: TRR 285 - Subproject A05"}],"_id":"58491","user_id":"84990","article_number":"157","publication_status":"published","publication_identifier":{"issn":["2504-4494"]},"citation":{"mla":"Friedlein, Johannes, et al. “Material Parameter Identification for a Stress-State-Dependent Ductile Damage and Failure Model Applied to Clinch Joining.” <i>Journal of Manufacturing and Materials Processing</i>, vol. 8, no. 4, 157, MDPI AG, 2024, doi:<a href=\"https://doi.org/10.3390/jmmp8040157\">10.3390/jmmp8040157</a>.","short":"J. Friedlein, M. Böhnke, M. Schlichter, M. Bobbert, G. Meschut, J. Mergheim, P. Steinmann, Journal of Manufacturing and Materials Processing 8 (2024).","bibtex":"@article{Friedlein_Böhnke_Schlichter_Bobbert_Meschut_Mergheim_Steinmann_2024, title={Material Parameter Identification for a Stress-State-Dependent Ductile Damage and Failure Model Applied to Clinch Joining}, volume={8}, DOI={<a href=\"https://doi.org/10.3390/jmmp8040157\">10.3390/jmmp8040157</a>}, number={4157}, journal={Journal of Manufacturing and Materials Processing}, publisher={MDPI AG}, author={Friedlein, Johannes and Böhnke, Max and Schlichter, Malte and Bobbert, Mathias and Meschut, Gerson and Mergheim, Julia and Steinmann, Paul}, year={2024} }","apa":"Friedlein, J., Böhnke, M., Schlichter, M., Bobbert, M., Meschut, G., Mergheim, J., &#38; Steinmann, P. (2024). Material Parameter Identification for a Stress-State-Dependent Ductile Damage and Failure Model Applied to Clinch Joining. <i>Journal of Manufacturing and Materials Processing</i>, <i>8</i>(4), Article 157. <a href=\"https://doi.org/10.3390/jmmp8040157\">https://doi.org/10.3390/jmmp8040157</a>","ieee":"J. Friedlein <i>et al.</i>, “Material Parameter Identification for a Stress-State-Dependent Ductile Damage and Failure Model Applied to Clinch Joining,” <i>Journal of Manufacturing and Materials Processing</i>, vol. 8, no. 4, Art. no. 157, 2024, doi: <a href=\"https://doi.org/10.3390/jmmp8040157\">10.3390/jmmp8040157</a>.","chicago":"Friedlein, Johannes, Max Böhnke, Malte Schlichter, Mathias Bobbert, Gerson Meschut, Julia Mergheim, and Paul Steinmann. “Material Parameter Identification for a Stress-State-Dependent Ductile Damage and Failure Model Applied to Clinch Joining.” <i>Journal of Manufacturing and Materials Processing</i> 8, no. 4 (2024). <a href=\"https://doi.org/10.3390/jmmp8040157\">https://doi.org/10.3390/jmmp8040157</a>.","ama":"Friedlein J, Böhnke M, Schlichter M, et al. Material Parameter Identification for a Stress-State-Dependent Ductile Damage and Failure Model Applied to Clinch Joining. <i>Journal of Manufacturing and Materials Processing</i>. 2024;8(4). doi:<a href=\"https://doi.org/10.3390/jmmp8040157\">10.3390/jmmp8040157</a>"},"intvolume":"         8","date_updated":"2025-01-31T17:03:34Z","author":[{"full_name":"Friedlein, Johannes","last_name":"Friedlein","first_name":"Johannes"},{"first_name":"Max","full_name":"Böhnke, Max","last_name":"Böhnke"},{"first_name":"Malte","last_name":"Schlichter","full_name":"Schlichter, Malte"},{"first_name":"Mathias","full_name":"Bobbert, Mathias","last_name":"Bobbert"},{"first_name":"Gerson","last_name":"Meschut","full_name":"Meschut, Gerson"},{"first_name":"Julia","last_name":"Mergheim","full_name":"Mergheim, Julia"},{"first_name":"Paul","full_name":"Steinmann, Paul","last_name":"Steinmann"}],"volume":8,"doi":"10.3390/jmmp8040157"},{"year":"2023","intvolume":"        99","citation":{"chicago":"Friedlein, Johannes, Julia Mergheim, and Paul Steinmann. “Efficient Gradient Enhancements for Plasticity with Ductile Damage in the Logarithmic Strain Space.” <i>European Journal of Mechanics - A/Solids</i> 99 (2023). <a href=\"https://doi.org/10.1016/j.euromechsol.2023.104946\">https://doi.org/10.1016/j.euromechsol.2023.104946</a>.","ieee":"J. Friedlein, J. Mergheim, and P. Steinmann, “Efficient gradient enhancements for plasticity with ductile damage in the logarithmic strain space,” <i>European Journal of Mechanics - A/Solids</i>, vol. 99, Art. no. 104946, 2023, doi: <a href=\"https://doi.org/10.1016/j.euromechsol.2023.104946\">10.1016/j.euromechsol.2023.104946</a>.","bibtex":"@article{Friedlein_Mergheim_Steinmann_2023, title={Efficient gradient enhancements for plasticity with ductile damage in the logarithmic strain space}, volume={99}, DOI={<a href=\"https://doi.org/10.1016/j.euromechsol.2023.104946\">10.1016/j.euromechsol.2023.104946</a>}, number={104946}, journal={European Journal of Mechanics - A/Solids}, publisher={Elsevier BV}, author={Friedlein, Johannes and Mergheim, Julia and Steinmann, Paul}, year={2023} }","short":"J. Friedlein, J. Mergheim, P. Steinmann, European Journal of Mechanics - A/Solids 99 (2023).","mla":"Friedlein, Johannes, et al. “Efficient Gradient Enhancements for Plasticity with Ductile Damage in the Logarithmic Strain Space.” <i>European Journal of Mechanics - A/Solids</i>, vol. 99, 104946, Elsevier BV, 2023, doi:<a href=\"https://doi.org/10.1016/j.euromechsol.2023.104946\">10.1016/j.euromechsol.2023.104946</a>.","ama":"Friedlein J, Mergheim J, Steinmann P. Efficient gradient enhancements for plasticity with ductile damage in the logarithmic strain space. <i>European Journal of Mechanics - A/Solids</i>. 2023;99. doi:<a href=\"https://doi.org/10.1016/j.euromechsol.2023.104946\">10.1016/j.euromechsol.2023.104946</a>","apa":"Friedlein, J., Mergheim, J., &#38; Steinmann, P. (2023). Efficient gradient enhancements for plasticity with ductile damage in the logarithmic strain space. <i>European Journal of Mechanics - A/Solids</i>, <i>99</i>, Article 104946. <a href=\"https://doi.org/10.1016/j.euromechsol.2023.104946\">https://doi.org/10.1016/j.euromechsol.2023.104946</a>"},"publication_identifier":{"issn":["0997-7538"]},"publication_status":"published","title":"Efficient gradient enhancements for plasticity with ductile damage in the logarithmic strain space","doi":"10.1016/j.euromechsol.2023.104946","publisher":"Elsevier BV","date_updated":"2026-02-24T14:37:05Z","volume":99,"date_created":"2024-09-10T15:23:49Z","author":[{"first_name":"Johannes","last_name":"Friedlein","full_name":"Friedlein, Johannes"},{"full_name":"Mergheim, Julia","last_name":"Mergheim","first_name":"Julia"},{"first_name":"Paul","last_name":"Steinmann","full_name":"Steinmann, Paul"}],"abstract":[{"text":"We contrast different gradient-enhancements for plasticity-damage material models in the logarithmic strain space and compare them to reference models based on multiplicative plasticity. The models being compared include plasticity - gradient-damage, where the gradient-enhancement is applied on the local damage variable, and gradient-plasticity - damage with a gradient-enhanced plastic hardening variable. Thereby, gradient-plasticity proved to be able to simultaneously regularise plastic and ductile (plasticity-driven) damage localisation as confirmed by numerical localisation analyses. This appears to be especially advantageous for logarithmic strain space plasticity-damage, because of the observed plastic localisation even for the case of plasticity with hardening. Even though gradient-plasticity appears to be numerically more demanding, two numerical examples indicate a good robustness and mesh objectivity in the softening regime. Moreover, the internal length for plasticity is able to adjust the damage zone width, similarly to gradient-damage, however ensuring a priori that damage takes place exclusively inside the plastic zone.","lang":"eng"}],"status":"public","publication":"European Journal of Mechanics - A/Solids","type":"journal_article","keyword":["Finite plasticity","Logarithmic strain space","Ductile damage","Gradient-enhancement","Gradient-plasticity","Gradient-damage","Loss of ellipticity"],"article_type":"original","article_number":"104946","language":[{"iso":"eng"}],"_id":"56097","project":[{"_id":"130","name":"TRR 285: TRR 285"},{"name":"TRR 285 - A: TRR 285 - Project Area A","_id":"131"},{"_id":"139","name":"TRR 285 – A05: TRR 285 - Subproject A05"},{"name":"TRR 285:  Methodenentwicklung zur mechanischen Fügbarkeit in wandlungsfähigen Prozessketten","_id":"130"}],"user_id":"84990"},{"keyword":["Ductile damage","stress state","small punch test","triaxiality","lode angle parameter"],"language":[{"iso":"eng"}],"abstract":[{"text":"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.","lang":"eng"}],"publication":"Engineering Failure Analysis","title":"Influence of cutting clearance and punch geometry on the stress state in small punch test ","publisher":"Elsevier","date_created":"2021-11-07T20:34:51Z","year":"2022","quality_controlled":"1","issue":"c","article_type":"original","_id":"27186","department":[{"_id":"157"}],"user_id":"71269","status":"public","type":"journal_article","doi":"10.1016/j.engfailanal.2022.106183","date_updated":"2022-04-25T07:48:20Z","volume":136,"author":[{"id":"71269","full_name":"Otroshi, Mortaza","last_name":"Otroshi","orcid":"0000-0002-8652-9209","first_name":"Mortaza"},{"first_name":"Gerson","orcid":"0000-0002-2763-1246","last_name":"Meschut","full_name":"Meschut, Gerson","id":"32056"}],"intvolume":"       136","citation":{"ama":"Otroshi M, Meschut G. Influence of cutting clearance and punch geometry on the stress state in small punch test . <i>Engineering Failure Analysis</i>. 2022;136(c). doi:<a href=\"https://doi.org/10.1016/j.engfailanal.2022.106183\">10.1016/j.engfailanal.2022.106183</a>","ieee":"M. Otroshi and G. Meschut, “Influence of cutting clearance and punch geometry on the stress state in small punch test ,” <i>Engineering Failure Analysis</i>, vol. 136, no. c, 2022, doi: <a href=\"https://doi.org/10.1016/j.engfailanal.2022.106183\">10.1016/j.engfailanal.2022.106183</a>.","chicago":"Otroshi, Mortaza, and Gerson Meschut. “Influence of Cutting Clearance and Punch Geometry on the Stress State in Small Punch Test .” <i>Engineering Failure Analysis</i> 136, no. c (2022). <a href=\"https://doi.org/10.1016/j.engfailanal.2022.106183\">https://doi.org/10.1016/j.engfailanal.2022.106183</a>.","mla":"Otroshi, Mortaza, and Gerson Meschut. “Influence of Cutting Clearance and Punch Geometry on the Stress State in Small Punch Test .” <i>Engineering Failure Analysis</i>, vol. 136, no. c, Elsevier, 2022, doi:<a href=\"https://doi.org/10.1016/j.engfailanal.2022.106183\">10.1016/j.engfailanal.2022.106183</a>.","bibtex":"@article{Otroshi_Meschut_2022, title={Influence of cutting clearance and punch geometry on the stress state in small punch test }, volume={136}, DOI={<a href=\"https://doi.org/10.1016/j.engfailanal.2022.106183\">10.1016/j.engfailanal.2022.106183</a>}, number={c}, journal={Engineering Failure Analysis}, publisher={Elsevier}, author={Otroshi, Mortaza and Meschut, Gerson}, year={2022} }","short":"M. Otroshi, G. Meschut, Engineering Failure Analysis 136 (2022).","apa":"Otroshi, M., &#38; Meschut, G. (2022). Influence of cutting clearance and punch geometry on the stress state in small punch test . <i>Engineering Failure Analysis</i>, <i>136</i>(c). <a href=\"https://doi.org/10.1016/j.engfailanal.2022.106183\">https://doi.org/10.1016/j.engfailanal.2022.106183</a>"},"publication_identifier":{"issn":["1350-6307"]},"publication_status":"published"}]