The effect of damage and temperature on electrical impedance of SiCf/SiC mini-composites and a preliminary decoupling method

This letter presents a preliminary method for decoupling and monitoring damage and temperature in SiC fiberreinforced SiC matrix mini-composites using electrical impedance. The impact of damage on impedance characteristics during uniaxial tension is elucidated by decomposing the impedance data into real and imaginary components. An equivalent circuit model, which accounts for the influence of electrode effects, is developed to interpret the experimental findings. Impedance measurements were conducted on pristine and pre-damaged specimens under a temperature-controlled environment at frequencies ranging from 10 Hz to 5 MHz. The reactance is found to be strongly correlated with damage progression and remains unaffected by changes in resistivity due to thermoresistive effects. This finding facilitates the decoupling and concurrent monitoring of damage and temperature conditions in ceramic matrix composite structures using only electrical impedance.