Effects of temperature and loading speed on interface-dominated strength in fibre/polymer composites: An evaluation for in-situ environment

The present investigation intends to study the influence of crosshead velocity and in-situ environmental conditioning i.e. high temperature and cryogenic temperature on micromechanical performance of glass fibre/epoxy, carbon fibre/epoxy and Kevlar fibre/epoxy polymer composites. 3-point short beam shear tests were conducted on the conditioned specimens to evaluate the interfacial properties and failure modes which are related to mechanical properties of the composites. The effect of crosshead velocity (within the range 1-103 mm/min) on the interlaminar shear strength (ILSS) of all the three composite systems at different temperatures was studied. The glass transition temperature (T-g) of conditioned samples were measured by differential scanning calorimetry (DSC) in the temperature range of 25 degrees C to 150 degrees C temperature. At 1 mm/min loading rate, for both glass/epoxy and carbon/epoxy composites maximum increase in ILSS value was about 85.72% with respect to ambient, while for Kevlar/epoxy composite 31.77% reduction in ILSS was observed at -100 degrees C temperature. (C) 2014 Elsevier Ltd. All rights reserved.