Critical self-heating temperature during fatigue of polymeric composites under cyclic loading
Andrzej Katunin
Quarterly No. 1, 2012 pages 72-76
DOI:
keywords: polymeric layered composites, self-heating effect, critical self-heating temperature, thermal fatigue
abstract This paper deals with the results of an experimental study of the occurrence of the self-heating effect during cyclic fatigue loading of plates made of polymeric composites. The evolution of self-heating temperature distributions was registered by infrared camera from the beginning of loading till the breakdown of the specimens. During the experiments it was observed that the process of thermal fatigue of the composite elements could be divided to three phases. It was observed, that on the transition border of the second and third phases of thermal fatigue, a crack initiates, which is caused both by increasing the self-heating temperature and mechanical fatigue. This moment corresponds w to the value of self-heating temperature, which is critical for given loading parameters. The critical self-heating temperature is strongly dependent on the excitation frequency, which results from the tim-temperature superposition principle. The influence of the excitation frequency and length of the specimens on the value of critical self-heating temperature was investigated. Based on experimental data, the empirical model of thermal fatigue, which uses the master curve of dynamic storage modulus, was proposed. The obtained experimental results and proposed fatigue model could be used in operation and structural health monitoring problems for the prediction of critical loading parameters of elements made of polymeric composites.