Numerical simulation of crack propagation and coalescence in marine cast iron materials using ordinary state-based peridynamics

Abstract

Fracturing is one of the major failure modes in marine structures. It is important to investigate the crack propagation and fracture behavior of cast iron material to prevent brittle failure and protect the structural safety of ship equipment. Classical continuum mechanics (CCM) has intrinsic shortcomings in simulating the fracture of solid materials. Peridynamics (PD) is a new nonlocal form of CCM that is highly suitable for the investigations of material failure. In the present study, a damage model, fracture criterion, and nonlinear characteristic are incorporated into the extended ordinary state-based peridynamics (OSPD) to simulate the initiation, propagation and coalescence of the preexisting flaws in marine cast iron materials subjected to tensile loads. First, the linear and nonlinear force functions of the failure process of the extended OSPD were constructed, and a new damage model and corresponding failure criterion were adopted. Then, the initiation, propagation and coalescence of the cracks in cast iron specimens with a single notch, double notch and multiple flows were investigated. Finally, the effects of arrays of cracks, Poisson's ratio and plate thickness on the crack propagation behaviors and peak loads were analyzed. The numerical results are in good agreement with the previous numerical and experimental observations.