Peridynamics methodology for elasto-viscoplastic ductile fracture

Abstract

This paper presents a novel peridynamics (PD) methodology and implementation approach for predicting the ductile fracture of elasto-viscoplastic materials. The proposed analysis model consists of three components: 1) an elasto-viscoplastic constitutive model based on modified Bodner-Partom (BP) constitutive theory; 2) bond damage prediction based on Wang’s unified damage theory; 3) crack growth prediction using the PD critical bond stretch criterion. The PD model for BP materials is realized under the ordinary state-based PD framework to define the bond-wise relationship between deformation state and force state. The use of a unified constitutive theory endows the present model with the characteristic of no yield criterion. In addition, the non-local nature of the PD framework allows discontinuities to naturally occur, thereby ensuring the present model can capture the initiation and propagation of ductile fracture. Simulations of the standard tension tests and mode-I compact tension tests were carried out to demonstrate the use of the PD model for BP materials in practical problems. Particle-wise indicators, representing the intensities of plasticity, damage and fracture, were extracted for post-processing. An in-depth analysis shows that the presented PD model for BP materials can effectively reproduce ductile fractures at the macro-scale, allowing a general PD description of ductile behavior, which brings a new outlook for the application of PD methods.