Abstract
In this paper we introduce a formula for the calculus of resistance to fracture for the composite plates with a random reinforcement’s distribution. Also, we give a formula for the calculus of upper limit of resistance to fracture for the composite plates, described as depending on the volumetric proportion of reinforcement. As applications, we give the variation of resistance to fracture depending on the volumetric proportion for two types of composite materials and, in addition, we determine the characteristic curves and the resistance to fracture for a traction test considering the two composite materials. Keywords: composite materials, strength to rupture, traction