Modeling and experimental study on electrical impedance response to damage accumulation in 2D C/SiC composites

Abstract

The electrical properties of C/SiC composites could be used for online and in-situ damage monitoring. To investigate alternating current (AC) impedance response to damage in the C/SiC composites, monotonic and incremental cyclic tensile tests were performed. Both AC impedance and acoustic emission (AE) techniques were applied to clarify the damage evolution during the tests. The relationship between damage and electrical impedance response was investigated and validated via macroscopic equivalent circuit models. The effects of longitudinal deformation and damage on AC impedance characteristics, including impedance magnitude and phase angle, were obtained from the models. Results showed that the longitudinal deformation increases the impedance magnitude and the phase angle, and the damage causes the impedance magnitude to increase and the phase angle to decrease. The phase angle is significantly sensitive to fiber breakage, which makes the AC-based method more suitable for online damage monitoring and final failure warning.