Calculation for path-domain independent J integral with elasto-viscoplastic consistent tangent operator concept-based boundary element methods

This paper presents an elasto-viscoplastic consistent tangent operator (CTO ) based boundary element formulation, and application for calculation of pa th-domain independent J integrals (extension of the classical J integrals) in nonlinear crack analysis. When viscoplastic deformation happens, the eff ective stresses around the crack tip in the nonlinear region is allowed to exceed the loading surface, and the pure plastic theory is not suitable for this situation. The concept of consistency employed in the solution of inc rement viscoplastic problem, plays a crucial role in preserving the quadrat ic rate asymptotic convergence of iterative schemes based on Newton's metho d. Therefore, this paper investigates the viscoplastic crack problem, and p resents an implicit v.scoplastic algorithm using the CTO concept in;a bound ary element framework for path-domain independent J integrals. Applications are presented with two numerical examples for viscoplastic crack problems and J integrals.