Analytical method for prediction of the strength of composite laminates

Abstract

The problem of prediction of the strength of composite laminates based on the properties of the individual laminae and the structure of the composite has been solved for the general case, where parametric equations were obtained for the limiting surface for a composite of arbitrary structure. However, application of these equations for practical computations requires a computer. Here the authors propose a technique allowing them to solve the considered problem by a simpler method for a composite with a structure in which there are identical layers with orientation angles (+{phi}{sub j}) and ({minus}{phi}{sub j}) where j = {bar 1},n, n is the number of layers. There are not other constraints on the structure surface of a composite of structure ({+-}{phi}){sub c} using the hypothesis that the strain rate field is uniform over the thickness of the packet of layers. The theoretical results are compared with the corresponding experimental results of other authors. For prediction of the strength of a composite or arbitrary structure, the authors have used the Voigt model in the theory of mixtures. As an example, they solve the problem of the supporting capacity of the composite tube of the drive shaft of an automobile.