Influence of carbon fibre orientation and heat flux on the thermomechanical response of CFRP using small-scale apparatus

Abstract

This study uses a small-scale apparatus to investigate the influence of carbon fibre orientation and heat flux on the thermomechanical response of carbon fibre reinforced polymer (CFRP). The proposed test apparatus allows the thermomechanical behaviour, relating to the mechanical performance degradation with particular surface temperature and temperature gradient of a CFRP, to be investigated. The motivation of this study is to understand the mechanical response of load-bearing CFRP materials during heating using a cone heater. Experiments were performed on CFRP specimens produced in four unique lay-ups to study their thermomechanical bending behaviour in terms of failure times, displacement, temperature distribution and failure modes. The results from this study show that different fibre orientations respond differently to thermomechanical loads. For example, it is observed that CFRP containing uni-directional [90°] fibres demonstrate the worst overall load-bearing response to thermomechanical loading conditions. In contrast, woven bi-directional [0°, 90°] fibres demonstrate the best. Uni-directional [0°] fibres and unwoven multi-directional [0°, ±45°, 90°] fibres present a modest overall load-bearing response to thermomechanical loading conditions. These results demonstrate that it is possible to systematically evaluate the performance of different fibre lay-ups and relate the failures to heating of the solid to the glass transition temperature and decomposition temperature of the polymer matrix.