Cohesive element analysis of fatigue delamination propagation in composite materials with improved crack tip tracking algorism

Abstract

A novel approach for accurate delamination propagation simulation under high-cycle fatigue loading with cohesive element is proposed. Traditional bilinear traction–separation relationship of cohesive zone model is associated with Paris-law related fatigue damage evaluation. An improved crack tip tracking technique is proposed containing a non-local algorism for propagation direction and effective propagation length calculation. The major advantage of the non-local algorism is its applicability to two-dimensional propagation problems with non-orthogonal meshes used. Test cases are investigated for method verification and illustration including fatigue delamination of (i) Double Cantilever Beam, 4-point End Notch Flexure and Mixed Mode Bending specimen with orthogonal meshes, (ii) Double Cantilever Beam specimen with non-orthogonal meshes, and (iii) centrally-loaded circular plate.