Evaluating plastic loads in torispherical heads using a new criterion of collapse

In ASME Design by Analysis, the plastic load of pressure vessels is established using the Twice Elastic Slope criterion of plastic collapse. This is based on a characteristic load-deformation plot obtained by inelastic analysis. This study investigates an alternative plastic criteria based on plastic work dissipation where the ratio of plastic to total work is monitored. Two sample analyses of medium thickness torispherical pressure vessels are presented. Elastic-perfectly plastic and strain hardening material models are considered in both small and large deformation analyses. The calculated plastic loads are assessed in comparison with experimental results from the literature.