DEPENDENCE OF GLARE DESTRUCTION MECHANISMS ON THE ELONGATION OF SAMPLES IN TESTS TO THREE-POINT FLEXURAL
Minggong Sha, Oleg A. Prokudin, Yury Solyaev, Sergey N. VAKHNEEV
Abstract
Tests on bending are one of the effective ways to experimentally determine the elasticity and shear moduli. An important task in the implementation of composite materials in aerospace structures is the development of methods for determining the physical and mechanical characteristics of materials. The paper presents of tests for three-point bending of samples of metal-polymer composite material "GLAss-REinforced" Fibre Metal Laminate (GLARE) are presented. Examined samples, consisting of 17 layers, for which apparent interlayer strength of the results of tests on three-point bending was established by the method of "short beam". It was established that for the studied samples, interlayer shear mechanisms were realized at the ratio of dimensions of length to thickness of at least 10. Localization of fracture occurs in the area of the central layer, which corresponds to the requirements of standards for conducting tests of the method of short beams. Nonetheless, such GLARE tests are always accompanied by the occurrence of significant plastic deformations associated with the presence of aluminum layers in the structure of the material. With the elongation of samples of more than 10, a fracture mechanism is realized in them, during which delamination and loss of stability of the outer layers on the compressed side of the sample occur. When the elongation of samples of less than 4 four is implemented in samples takes place, the mechanism of destruction of indentation type with large nonlinear deformations. According to the test results, the dependence of the realised fracture mechanisms on the elongation of the samples is determined.