ELASTO-PLASTIC LARGE DISPLACEMENT ANALYSIS OF SPATIAL SKELETAL STRUCTURES

In order to reduce the computational amount of the elasto-plastic analysis on skeletal structures appropriately, the plastic deformation is assumed being concentrated on both ends of an beam element. The end cross-sections of the beam element are discretized into several small areas. The elasto-plastic behavior of each small area is represented by the elasto-plasticity on its center which is analyzed to form the elasto-plastic stiffness of the end cross-section. The element#x02019;s elasto-plastic tangent stiffness is obtained from the integration of cross-section stiffness along the element by using Gauss-Lobatto quadrature scheme. The incremental constitutive relationship between the small areas is set up, which includes the isotropic hardening of material, and an effective algorithm is presented to correct the stresses which drift from the yield surface during material nonlinear analysis. Numerical examples show that this method is accurate, efficient and reliable.