Local stress analyses of composite materials using finite element methods. 1st report Saint-Venant's end effects of laminate media.

Abstract

Saint-Venant's end effects to composite materials are frequently different from those to isotropic and homogeneous materials, therefore, the estimation of its effects is an important subject in relation to the evaluation of strength of composite materials. This paper is intended to establish the general method to estimate this Saint-Venant's end effects to composite materials, and the contents are as follows: (1) The finite element formulation to estimate Saint-Venant's end effects is established using the principle of virtual work and some example problems of laminate media are analysed by deyeloped method. It is shown, through these analyses, that the newly-defined characteristic length le is useful to evaluate the rate of attenuation of non-uniform local stress distribution. (2) The conventional elastic-plastic finite element analyses are carried out to the same examples, and the availability of developed method is confirmed. The end effects in case that plastic deformation occurs, are also discussed.