ANALYSIS OF ROTATING CRACK MODEL

This paper extends the standard rotating crack (RC) model to a formula tion with multiple orthogonal cracks. The corresponding stress evaluat ion algorithm is described, and a derivation of the tangent stiffness matrix is presented. The derivation is extended to the case of equal p rincipal strains, in which the classical formula for the tangent shear modulus fails. A condition excluding snapback of the stress-strain di agram for an arbitrary loading path is derived. Attention then shifts to stress locking, meaning here spurious stress transfer across widely opening cracks. The problem is illustrated by numerical examples. The mechanism of stress transfer is thoroughly analyzed, and the source o f locking is detected. A remedy and extension of the model to a nonloc al formulation is described in a separate paper.