Element-Size Independent Analysis of Elasto-Plastic Damage Behaviors of Framed Structures

The adaptively shifted integration (ASI) technique and continuum damage mechanics are applied to the nonlinear finite element analysis of framed structures modeled by linear Timoshenko beam elements. A new form of evolution equation of damage, which is a function of plastic relative rotational angles, is introduced in order to remove the mesh-dependence caused by the strain-dependence of damage. The elasto-plastic damage behavior of framed structures including yielding, damage initiation and growth can be accurately and efficiently predicted by the combination of the ASI technique and the new damage evolution equation. Some numerical studies are carried out in order to show the validity, especially the mesh-independence of the proposed computational method.