Numerical elastic fracture analysis of SENT test specimen subjected to non-linear loading

Abstract

Crack characterization of any component depends on specimen type and geometry, material properties, and loading pattern. The geometrical and material property dependency of crack description is well established in literature, but loading pattern influence is limited to classical Mode-I, II and III types. Here, an effort is made to relate the crack stress state for different load pattens and crack length to specimen width, (a/W) using 2D and 3D linear elastic fracture analysis. The crack stress state is characterized by KI and T-stress in the present analysis using ABAQUS software. The non-uniform load patterns were defined by a non-linear stress distribution term σ (x). The stress distributions applied on the crack faces and were classified as constant, linear, parabolic, and cubic. The a/W varied as 0.2, 0.4, 0.6, and 0.8 to account the in-plane dimension effect on crack driving parameters. The 3D normalized KI and T-stress magnitudes were directly proportional to a/W. The normalized KI magnitudes decreased in the stress distribution order of constant, linear, parabolic and cubic. 3D normalized KI and T-stress values represented the real stress state of the crack. To ease the complex computational simulations, simple equations were proposed to estimate the normalized KI and T-stress for the different load patterns and a/W. To avoid the conservatism in component design, an attempt is made to represent the real load patterns through constraint inclusiveness in the 3D fracture analysis.