Evaluation of Glass Fibre Reinforced Polymer Composites Under the Exposure to Up and Down-Thermal Shocks

摘要

The choice of GFRP composites for use as structural components in aerospace, marine and civil infrastructures has already gained momentum. Such a choice demands evaluation of the material under exposure to thermal shock during real time applications. The present work is an attempt in this direction. The GFRP composite test specimens are exposed to up and down thermal shocks of different lengths of time. The 3-point bend test reveals general decreasing trend in ILSS for both the shock treated composite samples, despite of a little enhancement in the same for the initial duration of up-thermal shock and final duration of down-thermal shock. The huge misfit of strain at the interface due to large thermal gradient would have been resulted the diminution of ILSS values. The glass transition temperature (T_g) of the composite specimens being the function of thermal shock treatment observed to be less in case of up-thermal shock. The increase in T_g value of composite specimens exposed to down-thermal shock puts a signature of post-curing phenomenon in polymeric resin. Scanning electron micrographs of fractured surface of virgin and shock treated composites exhibit some chief mode of failures being fibre pull-out, fiber/matrix debonding, matrix cracking and crazing, fibre breakage etc.