Infrared Thermography for Non-destructive Evaluation of 2D C/SiC Composites Under Fatigue Loading

摘要

Fatigue tests of 2D C/SiC composites were performed on an Instron material testing machine.Constant-amplitude cyclic loading,with stress ratio (σmin/σmax) of 0.1 and sinusoidal frequency of 10Hz,were applied on plain and centre-holed plate specimens.Utilizing an infrared (IR) thermography system,the evolution of the surface temperature fields were monitored during the fatigue process.Damage evolution was discussed based on the variations of the modulus and the maximum temperature increment (△T) derived from IR image.At lower stress levels,△T rose quickly in the early cyclic stage and went steady as cycles processed.When the applied stress exceeded the fatigue endurance limit,△T rose rapidly until specimen failure.By analyzing △T during fatigue loading,it was possible to evaluate the damage evolution.△T had fairly well agreement with the damage evolution derived from modulus,and it could be used to predict the damage evolution of 2D C/SiC composites.