Plastic instability behavior explained by a new damage based model
Reformulating plastic instabilities within a damage-like variational framework
Computational Engineering, Finance, and Science
Summary
Materials like metals and soils can suddenly weaken and change shape in unexpected ways, causing things like cracks or collapses. This happens because of small zones where stress builds and softens the material, but studying these zones directly is difficult. The authors created a new mathematical way to describe this behavior by treating the weakening as if it were damage that grows inside the material. This approach helps connect different problems and can use advanced techniques to avoid common calculation problems in simulations.
What this means in practice
- •For structural engineers: Improve simulation tools to predict failure in metals and soils more reliably by reducing spurious localized softening effects during stress analysis.
- •For materials scientists: Use a unified framework for modeling plastic instabilities to design new metamaterials with predictable collapse behavior under stress.
Authors
Baptiste Reyne
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.