MODELING OF THE ULTIMATE STRENGTH CHARACTERISTICS OF POLYMER FRICTIONAL COMPOSITES WITH CHAOTICALLY ORIENTED GLASS FIBERS AND DISPERSED ADDITIVES OF RUBBER, ALUMINA, GRAPHITE AND BARITE

The paper solves the problem of constructing a model and carrying out numerical calculations of the values of the ultimate strength indicators for uniaxial compression of polymeric frictional composites. Epoxyphenol-based composites reinforced with short E-glass fibers randomly oriented in the space of the material and dispersed additives of rubber, alumina, graphite and barite are considered. In the simulation original method for predicting the ultimate strength characteristics of matrix composites is used, according to which a compressive load applied to the composite in a certain direction becomes destructive when the internal stress in the polymer matrix begins to exceed its ultimate strength. This method is based on the generalized singular approximation of random field theory, the concept of the stress concentration operator (tensor of the fourth rank), which connects the local (internal) values of the stress tensor with the average (external) stresses over the material, and information on the strength properties of the matrix. The dependences of the values of the ultimate strength indicators under uniaxial compression of polymeric frictional composites on variations in the volume concentrations of fillers – E-glass fibers, dispersed inclusions of rubber and mineral powder, consisting of alumina, graphite and barite in equal volume fractions – have been investigated. As a result of the carried out model calculations, it was found that an increase in the volumetric content of rubber inclusions leads to a weakening of the strength indicators of model composites, which in this case change according to a law close to linear. It is shown that an increase in the concentration of other fillers (both glass fibers and inclusions of mineral powder) leads to a significant improvement in the ultimate strength characteristics of polymeric frictional composite materials, while the nature of the dependences is monotonic.

modeling, polymeric frictional composite, inclusion, matrix, stress concentration operator, mechanical strength