New Strain-Energy-Based Coupled Elastoplastic Two-Parameter Damage and Healing Models for Earth-Moving Processes

Abstract

Novel strain–energy-based coupled elastoplastic two-parameter damage and healing formulations for geomaterials are developed and implemented for a numerical simulation of two-dimensional earth-moving processes. A new class of elastoplastic damage–healing models is proposed within an initial-elastic strain–energy-based framework. The governing incremental damage and healing evolutions are coupled in volumetric and deviatoric parts and characterized through the effective stress concept. The plastic flow is established via an additive split of the stress tensor. Specifically, we introduce four characteristic energy norms of the tensile volumetric, tensile deviatoric, compressive volumetric, and compressive deviatoric strain tensors, respectively, for the corresponding volumetric and deviatoric damage and healing mechanisms. By adopting a micromechanics-motivated damage characterization (P⁺) and a healing characterization (P^–) in the volumetric and deviatoric parts, the proposed two-parameter damage–healing models are implemented to demonstrate considerable versatility on numerical simulations of earth-moving processes. New computational algorithms are systematically developed based on the two-step operator splitting methodology. The volumetric and deviatoric elastic-damage–healing predictor and the effective plastic corrector are implemented within the Reproducing Kernel Particle Method (RKPM) meshfree codes. Numerical examples under earth excavation, transport, and compaction are presented to illustrate salient features of soils such as shear band and partial recovery of soil stiffness due to compaction by the new two-parameter damage–healing models.