ELASTO-PLASTIC ANALYSIS OF ISOTROPIC AND ANISOTROPIC PLATES

Abstract

For many-years, the analysis and design of structures have been based on a linear theory of elasticity, assuming isotropic behaviour of the constituent materials. However, present day numerical capabilities readily allow the collapse behaviour to be modelled, accounting for stress redistribution due to plastic behaviour. Also it is well known that most of structural materials exhibit some degree of anisotropy. Some materials, such as timber, are naturally anisotropic; cold-worked metal sheet manifest predominant directional properties which are intensified with increasing degree of plastic deformation. Recent interest and increase usage of advanced fibrous composite materials has made the assessments of the effects of anisotropy on the behaviour of the structural elements mandatory. In the present work, elasto-plastic analysis of plates has been carried out by means of finite element method. The accommodation of variable material properties not only along the surface of the structures but also through the thickness is made possible by the discrete layered approach. A numerical model applicable for the analysis of anisotropic plate is. developed using 9 noded Lagrange element. The finite element procedure adopted for elasto-plastic analysis follows the initial stress approach. Linear geometric behaviour is assumed and plastic yielding based on Huber-Mises yield surface is adopted in the present work. It has been found out the anisotropic material shows more stiffer behaviour