Evaluation and Optimization of the GISSMO Damage Model in AH36 Steel

Abstract In ship structural analysis, evaluating damage is essential for maintaining the safety and reliability of vessels under various operational conditions. Ships are often subjected to unpredictable and complex loading scenarios, requiring advanced methodologies to predict material failure behavior. The GISSMO (Generalized Incremental Stress State-dependent MOdel) is widely applied across various engineering fields, including automotive crash analysis, metal forming, and extrusion, to predict material damage and fracture. In this study, tensile tests were performed on five AH36 steel specimens with varying central geometries to capture a range of stress states. Finite element simulations were conducted using LS-DYNA, and the GISSMO parameters were optimized through LS-OPT. The calibrated parameters were validated against drop test results to assess their ability to replicate the actual material behavior. The findings confirm that the GISSMO model effectively captures damage evolution across various stress conditions, demonstrating its applicability for ship structure analysis.