Study of The Regularities of Postcritical Behavior and Failure of Specimens in the Tests of Composite Materials

Abstract

New experimental data on the regularities of deformation and fracture of layered GFRP and CFRP composites with various reinforcement schemes were obtained. Particular attention is paid to the manifestation of the postcritical behavior of composites, which is characterized by a decrease in the load that the sample is able to perceive, with a monotonous increase in displacements. In this case, the postcritical deformation stage is associated with the development of damage accumulated during the loading process, interaction of defects and subsequent partial destruction of the structural elements of the composite material. The tests were carried out on the samples of various shapes under three-point bending in a wide range of temperatures. The influence of temperature on the regularities of deformation and fracture of polymer composites and the realization degree of the postcritical deformation stage has been estimated. Methodical issues of experimental study of the effect of the rigidity of the loading system on the postcritical deformation and destruction of polymer composites under three-point bending and interlayer shear (short beam method) are considered when using various combinations of disc springs in the loading circuit. Experimental data on the effect of the rigidity of the loading system on the realization of the equilibrium stage of postcritical deformation during the destruction of composite materials during the interlayer shear are obtained. The structure of the destroyed prototypes was analyzed.