Ductile Crack Propagation under Monotonic Loading

Abstract

For specimens with relatively uniform stress and strain distribution, e.g., smooth tension coupons, a crack propagates almost simultaneously as the crack initiates. For most of the cases, a ductile crack propagation rule is required to accurately evaluate the whole cracking process. In this chapter, a crack propagation rule based on an energy balance approach is added to the crack initiation rule in the previous chapter, where deterioration of material is also considered. A method to calibrate the crack propagation correlated parameter using tension coupon test results is proposed. A series of single-edge V-notched and U-notched tension coupons made of high-strength steel are manufactured and experimentally pulled to rupture under quasi-static loading. Numerical cracking simulation is also conducted and compared with the experimental results. Comparison results indicate that the ductile fracture model can well predict both crack initiation and crack propagation of structural steel under high triaxialities.