EVALUATION OF THE EFFECT OF ELEVATED TEMPERATURE AND PRELIMINARY THERMAL AGING ON THE RESIDUAL MECHANICAL PROPERTIES OF A STRUCTURAL FIBERGLASS USING THE SIGNALS OF ACOUSTIC EMISSION

The paper presents the results of mechanical tests on an aviation structural fiberglass based on a VPS-48 prepreg during quasi-static tests in the uniaxial tension and interlaminar shear. The results of studies on the effect of elevated temperature and preliminary thermal aging on the residual mechanical properties of the material were shown. Results of a preliminary thermal aging (under different regimes) on the mechanical characteristics, the nature of deformation and the implementation of various mechanisms of destruction the composite during interlaminar shear tests were obtained. The laws of changes in the properties of the thermally aged fiberglass during tensile and interlaminar shear tests were studied on the basis of a comprehensive analysis of its mechanical characteristics and AE signals. The time dependences of AE signal parameters for fiberglass specimens were obtained. The paper illustrates distributions of the frequency of spectral maximum of acoustic emission signals obtained after the destruction of specimens with different regimes of preliminary thermal aging presented graphically. An analysis of the microstructure of the surface of specimens before and after a preliminary thermal aging was carried out.