[{"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","keyword":["Finite plasticity","Ductile damage","Gradient-enhancement","Stress-state dependency","Failure"],"language":[{"iso":"eng"}],"year":"2025","title":"Modelling of stress-state-dependent ductile damage with gradient-enhancement exemplified for clinch joining","publisher":"Elsevier BV","date_created":"2025-01-31T17:04:12Z","status":"public","type":"journal_article","article_type":"original","article_number":"106026","_id":"58492","project":[{"grant_number":"418701707","_id":"130","name":"TRR 285: TRR 285:  Methodenentwicklung zur mechanischen Fügbarkeit in wandlungsfähigen Prozessketten"},{"name":"TRR 285 - A: TRR 285 - Project Area A","_id":"131"},{"_id":"139","name":"TRR 285 – A05: TRR 285 - Subproject A05"}],"user_id":"84990","intvolume":"       196","citation":{"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>.","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>","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>","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>.","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} }","short":"J. Friedlein, J. Mergheim, P. Steinmann, Journal of the Mechanics and Physics of Solids 196 (2025)."},"publication_identifier":{"issn":["0022-5096"]},"publication_status":"published","doi":"10.1016/j.jmps.2025.106026","date_updated":"2025-01-31T17:06:22Z","volume":196,"author":[{"first_name":"Johannes","full_name":"Friedlein, Johannes","last_name":"Friedlein"},{"first_name":"Julia","full_name":"Mergheim, Julia","last_name":"Mergheim"},{"last_name":"Steinmann","full_name":"Steinmann, Paul","first_name":"Paul"}]},{"title":"Material Parameter Identification for a Stress-State-Dependent Ductile Damage and Failure Model Applied to Clinch Joining","publisher":"MDPI AG","date_created":"2025-01-31T16:59:13Z","year":"2024","issue":"4","keyword":["ductile damage","stress-state dependency","failure","parameter identification","punch test","clinching"],"language":[{"iso":"eng"}],"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>"}],"publication":"Journal of Manufacturing and Materials Processing","doi":"10.3390/jmmp8040157","date_updated":"2025-01-31T17:03:34Z","author":[{"last_name":"Friedlein","full_name":"Friedlein, Johannes","first_name":"Johannes"},{"first_name":"Max","last_name":"Böhnke","full_name":"Böhnke, Max"},{"first_name":"Malte","last_name":"Schlichter","full_name":"Schlichter, Malte"},{"first_name":"Mathias","full_name":"Bobbert, Mathias","last_name":"Bobbert"},{"first_name":"Gerson","full_name":"Meschut, Gerson","last_name":"Meschut"},{"last_name":"Mergheim","full_name":"Mergheim, Julia","first_name":"Julia"},{"first_name":"Paul","full_name":"Steinmann, Paul","last_name":"Steinmann"}],"volume":8,"citation":{"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>","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>","short":"J. Friedlein, M. Böhnke, M. Schlichter, M. Bobbert, G. Meschut, J. Mergheim, P. Steinmann, Journal of Manufacturing and Materials Processing 8 (2024).","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>.","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} }"},"intvolume":"         8","publication_status":"published","publication_identifier":{"issn":["2504-4494"]},"article_number":"157","project":[{"name":"TRR 285: TRR 285:  Methodenentwicklung zur mechanischen Fügbarkeit in wandlungsfähigen Prozessketten","_id":"130","grant_number":"418701707"},{"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","status":"public","type":"journal_article"}]