A design-experiment study of nonlinear properties of coal-plastic

Abstract

A design-experiment method of estimating and forecasting nonlinear deformation of unidirectional and layered coal-plastic with different angles of layers placed under quasi-static loading is proposed. The elastic properties of a layer were determined on the basis of test results of crossing-reinforced flat samples under stretching. It was assumed that the nonlinearity of a layer and of a stack with multiple layers stowed at different angles is determined by nonlinear deformation of the layer at shear in the layer’s plane, which was described with the help of a piecewise-linear approximation. To construct the defining relations of the pack, the theory of laminated plates was used. The investigation results showed a satisfactory agreement of calculated and experimental data.