A Criterion for Evaluating Plastic Collapse Load: Plastic Work-Tangent Criterion

A new criterion: plastic work-tangent (PWT) criterion for evaluating plastic collapse load in pressure vessel design by analysis is presented in this paper. According to the plastic work-load curve, when the tangent variation is less than a given value in the plastic phase, the corresponding load is the plastic collapse load. Application of the proposed criterion is illustrated by considering the elastic-plastic response of lower head of reactor pressure vessel (RPV) and nozzle intersection of RPV. It is proposed that this is because the PWT criterion more conveniently to use in finite element soft ANSYS and more efficiently to evaluate the plastic collapse load.