Ductile failure of flat plates containing two through-wall cracks: Experimental investigation and numerical

Multiple cracks are frequently detected in structural components and should be assessed aimed to judge whether they can be treated as individual cracks or be combined to a larger crack. To study the ductile failure and crack interaction behavior, tensile tests using flat plates with two through-wall cracks were conducted, and 3D digital image correlation method (3D-DIC) was applied to acquire the displacement and full-field strain measurement. A damage evolution model integrated with a non-monotonic fracture strain locus was implemented to model the ductile fracture and crack interaction. Simulation results including load-displacement curves and predicted crack coalescence results fit well to the experiment data. Effects of mesh size and cut-off value of stress on the simulation results were investigated to ensure the accuracy of finite element analysis. The findings show that FE predictions using non-monotonic fracture strain locus are not only superior to those using monotonic ones, but also more accurate than alignment and combination rules in fitness-for-service codes.

Automated summary

Studies were conducted on ductile failure and crack interaction in situations with multiple cracks, using tensile tests and 3D digital image correlation method. A damage evolution model was implemented to simulate ductile fracture and crack interaction, showing that using non-monotonic fracture strain locus in finite element predictions is more accurate and reliable.