Finite-Element Simulation of Ductile Fracture in Reduced Section Pull-Plates Using Micromechanics-Based Fracture Models

Abstract

Micromechanics-based models that capture interactions of stress and strain provide accurate criteria to predict ductile fracture in finite-element simulations of structural steel components. Two such models—the void growth model and the stress modified critical strain model are applied to a series of twelve pull-plate tests that represent reduced (or net) section conditions in bolted and reduced beam section connections. Two steel varieties, A572 Grade 50 and a high-performance Grade 70 bridge steel are investigated. The models are observed to predict fracture much more accurately than basic longitudinal strain criteria, by capturing stress–strain interactions that lead to fracture. The flat stress and strain gradients in these pull plates allow the use of relatively coarse finite-element meshes providing economy of computation while capturing fundamental material behavior and offering insights into localized ductile fracture effects.