ELASTICITY LAWS OF SOME UNIDIRECTIONAL FIBERS-REINFORCED LAMINAE SUBJECTED TO IN-PLANE LOADS

Abstract

Distributions of the transformed compliances and rigidities in case of [45] unidirectional glass fibers-reinforced composite laminae versus the variation of their fibers disposal angle are computed and plotted. The basic elasticity constants of an epoxy/glass fibers unidirectional reinforced lamina with 40% fibers volume fraction, being in a stress plane state has been also determined. An [0] epoxy/boron fibers unidirectional reinforced lamina with 60% fibers volume fraction subjected to biaxial stresses σxx and σyy has been also considered in the computing model. Another lamina taken into consideration in this simulation process is a unidirectional [-45] epoxy/boron fibers-reinforced lamina with 60% fibers volume fraction subjected to biaxial stresses σxx and σyy to compute the lamina’s strains εxx, εyy and γxy. This computing model put into evidence the fact that although the loading of y-axis direction is half of that on x-axis direction, the εyy strain is eight times greater than that on x-axis direction which means that the tensile strength transverse to the fibers direction is very low in case of the [0] epoxy/boron lamina. Although the tangential stress τxy = 0, the biaxial stress field causes a γxy strain in case of a [-45] epoxy/boron lamina.