Simulation of ductile fracture of structural steels with void growth model and a continuum damage criterion based on it

摘要

Ductile fracture of single-edge U-notched and V-notched specimens under monotonic tension was investigated. Both experimental and numerical studies were conducted. In the tests on eight specimens, all ductile fracture initiated at mid-thickness of the notch tips and propagated all the way across the width of the specimens. Obvious plastic deformation was observed during both the fracture initiation and propagation procedures. Ductile fracture of these specimens was then simulated with void growth model (VGM) and a continuum damage criterion based on VGM. Extremely fine mesh and relatively coarse mesh were adopted in finite element analysis for the simulation. Load-displacement curves and the entire ductile fracture procedures obtained with the two fracture criteria for all the eight specimens agreed well with corresponding test results or with each other, by which the accuracy of both fracture criteria was verified. The efficiency of the two fracture criteria was also discussed. It was found that the computational cost of VGM is unacceptably high due to the request of extremely fine mesh along the fracture surface. With the continuum damage criterion, the ductile fracture of structural steels can be simulated accurately enough at acceptable computational cost even for steel components or connections with complicated configurations.