A structure is often required to be loaded to the inelastic range with progressive stiffness degradation in Advanced Analysis, and therefore the post-yield response is monitored.

The basis of the plastic hinge method is cross-section plastification. Material yielding is accounted for by zero-length plastic hinges at one or both end of each element. Plasticity is assumed to be lumped only at the ends of an element, while the portion within the element is assumed to remain elastic throughout the analysis.

 

Figure1 A hybrid element with end springs for inelastic analysis

Figure2 Yield surface for plastic hinge