The numerical simulation of ultrasonic resonance in CFRP within voids

In order to identify the distribution character of void defects in carbon fiber reinforced polymer (CFRP), the ultrasonic resonance in CFRP containing voids was studied. The ideal model within no voids, model within uniformly distributed voids and model within centralized voids were built respectively based on finite element analysis software ANSYS. Then the ultrasonic spreading in the above models were numerically calculated. The ultrasonic echoes and their spectrums were analyzed. At last, the time-frequency images of the ultrasonic echo signals were generated for further analysis. The results are as follows. When the ultrasonic whose center frequency is close to the resonance frequency of the CFRP is used to test the CFRP, the ultrasonic in the ideal model within no voids can generate resonance and the frequency is consistent with the CFRP theoretical resonance frequency. The frequency of ultrasonic in model within uniformly distributed voids will slightly deviate from the theoretical resonance frequency. The frequency of ultrasonic in model within centralized voids will greatly deviate from the theoretical resonance frequency of CFRP. These conclusions can be used as the criterion for detecting void defects and the distribution of voids in CFRP.