Minimizing self-heating based fatigue degradation in polymeric composites by air cooling

The self-heating effect occurs during cyclic loading or vibrations of composite elements, which may significantly intensify structural degradation due to the rapid temperature increase, especially in the case of development of the non-stationary selfheating scenario. The self-heating temperature may pass its critical value during loading and dominate fatigue fracture of a structure. For minimizing the influence of self-heating during fatigue of polymeric composites the air cooling can be used in order to cool down the surface. In this study, the influence of air cooling on the fatigue and residual life of a cyclically loaded composite structure is investigated by theoretical analysis and preliminary experimental studies. The phenomenological model of self-heating of a composite structure during air cooling is presented and discussed with identification of possible scenarios of self-heating temperature evolution and including the forced cooling by the high-speed airflow. The preliminary experimental results show that the surface cooling has significant influence on the residual life of a structure, and, by heat removing, the durability of a structure being under the influence of the self-heating effect can be significantly extended. These observations allow for posing a conjecture that appropriately controlled air cooling of a surface of a loaded structure may prevent or at least minimize structural degradation during fatigue caused by the self-heating effect. 2019 The Authors. Published by Elsevier B.V.