THE INFLUENCE OF STRUCTURE FORMING FACTORS ON LOW-CYCLE FATIGUE OF A POLYMER COMPOSITE MATERIAL BASED ON FURFURAL ACETONE MONOMER (FAM)

Abstract

Research studies of polymer concretes are frequently carried out under the action of static loads while the material is affected by cyclic loads, most often, low-cycle as a result of its work in the structure. In the case when the level of stresses caused by these loads exceeds a certain limit, irreversible damage accumulation processes begin to occur in the material, which lead to the formation of cracks. In the future, the stress concentration at the edge of the crack contributes to its development. Most often cracks occur at the surface of the part, but sometimes in the thickness of the material. This process weakens the section and after some time, when the crack reaches a critical length, the part or structure is destroyed. As a rule, they are destroyed without visible residual deformations, even in cases when they are made of plastic materials. It was suggested that under the influence of variable stresses material gradually degenerates over time, as if "gets tired" (fatigued). Material fatigue is a process of gradual accumulation of damage under the influence of variable stresses, leading to the formation of cracks and destruction of the material. The peculiarities influencing low-cycle stresses on strength characteristics of polymer concretes based on furfural acetone monomer (FAM) are considered in the article. The regression equation has been obtained as a result of experimenting on a polymeric composite material which allowed constructing the response surface of the low-cycle fatigue of the polymeric composite material based on the resin of furfural acetone monomer. A second-order plan for three factors studying low-cycle fatigue of a tested composite material is also presented in the paper. It has been established that the ratio of the polymer component to the filler and the coarse aggregate spreading factor are the fundamental ideas influencing the cyclic durability of polymer concretes while the thickness of the polymer bonding layer is an insignificant factor.