Enhancement of steel/carbon fibre-reinforced polymer adhesively-bonded joints at elevated temperatures through curing

Abstract

Although carbon fibre-reinforced polymer (CFRP) a promising approach to the strengthening of existing steel structures, such an adhesively-bonded system exhibits a significant loss of stiffness and strength in an elevated temperature range. Curing at elevated temperature is examined in this paper, in order to enhance the mechanical performance in the elevated temperature range. Two types of epoxies - with and without carbon nanotube (CNT) modification - were used to prepare steel/CFRP adhesively-bonded joints and both were cured at room temperature (20 degreesC) and at an elevated temperature (80 degreesC), and then tested in tension at temperatures from 20 to 80 degreesC. Remarkable enhancement of stiffness and strength was found for the joints, with or without CNT modification, cured at the elevated temperature, compared to corresponding joints cured at room temperature. The partial safety factors used for laminates by hand lay-up were further evaluated for designing such joints under elevated temperatures.