Temperature dependence of interfacial strength of carbon-fiber-reinforced temperature-resistant polymer composites

In the present study, the temperature-dependence of fiber/matrix interfacial strength is discussed through temperature-controlled microbond testing and its numerical simulation. The tests are carried out from room temperature to 100 °C. The micromechanical testing machine debonds the interface and the load at which debonding occurs is measured. In the numerical simulation, thermal residual stress is calculated by considering the relaxation modulus and the time-temperature superposition principle for the resin, i.e. thermo-viscoelasticity, in order to obtain an accurate thermal residual stress. In order to reproduce the damage of resin unique to the microbond test, continuum damage mechanics and Christensen's failure criterion for multi-axial stress states are applied from ambient temperature to 100 °C. Interfacial debonding is simulated using a cohesive zone model. The interfacial strength is determined by comparing the analysis results with the experimental results. Results show that there is no obvious temperature dependence on interfacial strength; similar interface strengths are obtained over the range of temperatures studied.