An experimental investigation on the repeated impact response of glass/epoxy composites subjected to thermal ageing

In this study, the effect of thermal ageing on low velocity impact response of E-glass/epoxy composites was investigated. Together with single impact case, repeated impact response of the composite samples was also investigated. Impact energies were chosen as 20J, 40J, 60J, 80J and 100J for single impact tests while 20 J was chosen for repeated impact tests. The test coupons were cut out from composite panels with stacking sequence of [0/90](4s) and the dimensions of the specimens were 100 mm x 100 mm, with the nominal thickness of 4.2 mm. The conditioning humidity and temperature were chosen respectively as 70% and 95 degrees C, considering the glass-transition temperature (T-g) of the intact composites which was determined as 78 degrees C. The samples were exposed to ageing durations of 100, 400, 700,1000 and 1300 h by using a climatic test cabin. Along with images of damaged samples, variations of the impact characteristics such as absorbed energy, maximum contact force, maximum deflection and contact duration for successive impacts until perforation of the samples are provided. As a result of the study it is found that in addition to the mechanical properties, damage resistance of the E-glass/epoxy composites is significantly affected by the thermal ageing. (C) 2015 Elsevier Ltd. All rights reserved.