Effects of Thermal and Cryogenic Conditionings on Mechanical Behavior of Thermally Shocked Glass Fiber-Epoxy Composites

Abstract

A very large thermal expansion mismatch may result in weakening the fiber-matrix interface and/or a possible matrix cracking due to thermal shock stress. The short beam shear specimens of glass-epoxy composite were treated at 40 C for a certain time and then exposed to 40 C for different conditioning times. The treatment was performed in the opposite direction of thermal cycle. The three-point bend test was carried out at room temperature with different crosshead speeds. The debonding effect of different natures of thermal shock (up- and down-cycles) and strengthening phenomena of thermal conditionings (above and subzero temperature conditionings) were assessed in the present study for the different durations of conditioning and different states of thermal conditionings (thermal and cryogenic). The state of the interactions between fiber and polymer matrix by the treatment was reflected in the shear values of the composites.