Ductile fracture prediction in thin-walled structures through a novel damage model

Abstract

Damage models have significantly advanced predictions of ductile fractures in large, thin-walled structures like automobiles, ships, and aircraft. However, accurately predicting these fractures remains challenging due to variations in strain localization, ranging from biaxial compression to tension. This study introduces a specialized damage model for shell elements, utilizing data from shear, uniaxial, and plane tension tests. Our model notably improves failure displacement prediction under shear stress by 50 % compared to the digital image correlation technique. Additionally, by employing ratios from necking to failure displacements observed in tension tests, we regularized the fracture locus for 3.0 mm shell elements, encompassing the spectrum from biaxial compression to tension. Our proposed damage model offers enhanced accuracy in predicting the occurrence, shape, and force-displacement characteristics of ductile fractures in simulated three-point bending tests, compared to the Walters model. This advancement holds promise for improving the precision of ductile fracture predictions in practical engineering applications.

Keywords

• Shell element
• Ductile fracture
• Mesh dependence
• Stress triaxiality dependence
• Damage