SOME CONSIDERATION CONCERNING THE USE OF THE LAW OF MIXTURE IN THE IDENTIFICATION OF THE MECHANICAL PROPERTIES OF THE COMPOSITES

Abstract

In the case of the composite materials, made by two or more materials, currently is used the law of mixtures to compute the mechanical constants. The relations for these constants, obtained at the beginning of the XIX century by Reuss and Voigt, has the great advantage to write these in terms of percent of the phases, without taking into account the geometrical and structural properties. It is natural for these relations to approximate very good the values of the elastic constants only for some particular cases. The problem is how good are the presented formulas when is necessary to compute the values of the engineering constants and if it is necessary to use other formulas, that have the disadvantage to be complicated. The paper refers to the composite materials reinforced with long fibres in an elastic matrix.