Theoretical-experimental investigation of temperature evolution in laminated composites due to fatigue loading

摘要

A method based on the first law of thermodynamics has been developed to predict the temperature evolution in the laminated composite during the fatigue process. The damage energy, frictional energy, and irreversible works are calculated to obtain the dissipated energy in each cycle. A lot of experiments on T300/EPL1012 carbon/epoxy laminates has been carried out to characterize and evaluate the proposed procedure. An IR thermography camera has been set up to monitor the temperature of the external surface of the specimen undergoing cyclic loading. The results show that the temperature increases rapidly in the first 20% of total life, then increases gradually until final failure and suddenly increases at the instance of fracture. The variations of the slope of temperature evolution during the fatigue process could be utilized for estimation of the stage of fatigue life. The results show that in 90 degrees plies, the temperature grows more rapidly relative to 0 degrees plies and increases about 20 degrees C up to final failure. The developed model has the capability to predict the temperature evolution of laminated composites during cyclic loading which can be used in entropy-based models of fatigue life assessment and also for evaluating the temperature-dependent properties of the matrix during fatigue process.