Large deflection elasto-plastic analysis of frames using the weak-form quadrature element method

The newly developed weak-form quadrature element method is applied to large deflection elasto-plastic analysis of frames. Fiber section model is used to derive the nonlinear relation of section deformations and internal forces, and their interaction. Condensation of the internal degrees of freedom of an element to cater for large-scale structural analysis is introduced. One quadrature beam element is able to simulate the distributed plasticity of a frame member, taking into account large deflection effect, continuously varying cross sections and non-uniformly distributed loads. Three numerical examples are given to verify the convergence rate of the weak-form quadrature element method for large deflection elasto-plastic analysis of frames. As compared with those of other commonly-used methods, the weak-form quadrature element method is shown to be versatile, stable and efficient.

► A quadrature beam element for large deflection distributed plasticity analysis. ► The displacement-based quadrature element accommodates second-order effect. ► One quadrature element can simulate one frame member in elasto-plastic analysis. ► The quadrature element is more efficient than traditional finite elements for frames. ► The quadrature element has advantages over the force-based beam element.