🤖 AI Summary
This study addresses persistent bottlenecks in simulating plastic instability, including difficulties in experimental correlation, computational non-convergence, and mesh sensitivity. To overcome these challenges, this work proposes a damage-like variational framework that characterizes plastic softening as an internal variable, thereby decoupling hardening and softening behaviors. Furthermore, a field-independent constitutive model is established to bridge the theoretical gap between plastic instability and continuum damage mechanics, incorporating regularization techniques from fracture mechanics. The proposed approach effectively suppresses spurious localization, significantly enhances numerical convergence, and provides a unified description of diverse plastic instability phenomena.
📝 Abstract
Yield point phenomena in metals, anticracks in soils and snows, or planewise collapses in lattice metamaterials, are different manifestations of plastic instabilities characterized by stress softening and strain localization. Several independent constitutive descriptions exist and suffer from similar challenges: experimental difficulties to link local events to global measurements, and computational lack of convergence, spurious localization and mesh sensitivity. This work proposes a minimal field-agnostic constitutive framework where plastic softening is represented by a damage-like internal variable which explicitly separates stable hardening behavior from unstable softening. The resulting formulation admits a variational structure and can leverage regularization tools originally developed by the ductile fracture community. The framework aims at emphasizing similarities within plastic instability phenomena and establishing a bridge with continuum damage mechanics, to open a path towards regularized variational formulations of localized plastic flows.