About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
|
| Symposium
|
Verification, Calibration, and Validation Approaches for Mechanical Modeling of Metals
|
| Presentation Title |
Inverse Identification of Johnson-Cook Parameters from Dynamic Simulations and Nelder-Mead Simplex Method |
| Author(s) |
Kah Choong, Dinakar Sagapuram, Mike Prime |
| On-Site Speaker (Planned) |
Kah Choong |
| Abstract Scope |
Accurately predicting material response to high-strain rate applications such as ballistic impact, blast loading, and crashworthiness design remains a critical engineering problem where structural performance depends on reliable constitutive models and determination of their parameters. Direct measurements of the stress and strain during dynamic plasticity are typically costly or intractable due to its inherent nonlinearity and sensitivity to other variables such as strain rate and temperature. In this preliminary work, we build a Nelder-Mead optimization scheme coupled with ABAQUS simulations of dynamic experiments including the classical Taylor Impact and Richtmeyer-Meshkov Instabilities (RMI) tests to determine parameters of the Johnson-Cook model. We demonstrate an objective function formulation based on the post-impact Taylor cylinder that sufficiently distinguishes between poorly and adequately calibrated fits. Despite the issue of non-uniqueness, the adequately fitted stress-strain responses, across the range of strain, strain rates, and temperatures explored, closely match those obtained from a "ground-truth" simulation. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Computational Materials Science & Engineering, Modeling and Simulation, Mechanical Properties |