Strain Energy Density Fracture Criterion in Elastodynamic Mixed Mode Crack Propagation.

摘要

Sih's fracture criterion based on strain energy density, S, for mixed mode crack extension under static loading is extended to dynamic mixed mode, K(I), and K(II), crack propagation. Influence of the second order term, sigma(ox), which represents the non-singular constant stress acting parallel to the direction of crack propagation, on the S distribution surrounding the crack tip, is demonstrated. Numerical studies show that positive sigma(ox) enhances the fracture angle and negative sigma(ox) reduces the fracture angle irrespective of the sign of K(II)/K(I), when S is measured at a critical distance r(c) from the crack tip. This fracture criterion is verified by the crack curving results of dynamic photoelastic fracture specimens. Omission of sigma(ox) term leads to predicted fracture angles which are at variance with experimental data.