A hybrid Meshless-FEM field transfer technique minimizing numerical diffusion and preserving extreme values: Application to ductile crack simulation

摘要

We propose a hybrid 3D field transfer operator based on a moving least-squares meshless interpolation and designed to reduce numerical diffusion as well as to preserve extrema values during the adaptive analysis of a metal-forming process. An isotropic information point selection based on both distance and direction is implemented in the construction of the Diffuse Interpolation to take account of the steep gradient of the physical field in highly localized zones. An information compensation process addresses the problems of loss of interpolation accuracy and lack of information points near the geometric boundary. Results of transferring an analytically highly localized field using different transfer operators are compared to show the improvement offered by our field transfer operator in situations where mesh gradation is large and field gradients are steep. Our method is implemented in an iterative 3D h-adaptive methodology to simulate metal-forming processes. Its effectiveness and robustness are validated through a simulation of crack initiation and propagation in a tensile test with a specimen made of rolled steel.