Theoretical determination of the spread in the strength of fiberglass

Abstract

It is well known that structural defects lead to a concentration of stresses, thereby lowering the strength of fiberglass. Since the position of these defects in actual specimens is to a large extent random, the strength of these samples fluctuates, i.e., there is a distribution associated with strength tests. This distribution, in contrast to the stress field inside the fiberglass, can easily be determined experimentally.

In this article, we present examples of the calculation of stress concentration caused by different systems of fiber ruptures and, based on the results obtained, we calculate the spread in the strength of fiberglass, in which the starting system of defects has some regularity, resulting from the appearance of a new defect at a random point. It is assumed that the fiberglass consists of alternating fibers and bonding layers, and in addition, that the fibers function only by stretching and compressing, while the bonding agent functions only in shear.