A Nonlocal Damage-enhanced Lattice Particle Model for Ductile Fracture Analysis

Ductile fracture of metallic materials typically involves the elastoplastic deformation and associated damaging process. The nonlocal lattice particle method (LPM) can be extended to model this complex behavior. Recently, a distortional energy-based model is formulated into LPM to simulate J2 plasticity. However, this model is based on the incremental updating algorithm which needs very small loading steps to get reasonable results. This is time-consuming and unstable for large systems. Therefore, in this paper, a tensor-based return-mapping algorithm is proposed to deal with these deficiencies. The material deterioration process is modelled as a nonlocal damage evolution process. The particle-size/lattice dependency of macroscopic mechanical responses are handled properly by using the proposed model. Numerical examples of predicting the elastoplastic behavior of engineering structures with/without damage and fracture are also provided. A multi-threaded implementation of LPM using C is available on the website: https://github.com/ymlasu/LPM-C.