Strength equation of composite materials and fractal dimension of cracks

The paper presents the derivation of a strength equation of composite materials that can be represented in the form of polydisperse systems. The theoretical analysis shows that the process of composite material structure formation is anti-persistent. A structural transition was revealed at a volume defect concentration of 0.65, which leads to a sharp decrease in the relative material strength. The dependence for calculating the crack system fractal dimension based on the experimental dependences of the material strength and porosity is justified.