Ultrasonic characterization of CFRP anisotropy

In the paper, a new method for evaluation of CFRP (carbon fiber-reinforced plastic) anisotropy is presented. Such material is composed of carbon fabric, i. e. epoxy layers with different orientation, which makes material stronger and lighter. These specific properties are generally used in aerospace and automotive industry. Measurement method is based on a special multi-directional ultrasonic probe with eight built-in piezoceramic elements used for elastic wave propagation measurement. CFRP anisotropy evaluation is twofold: the first method is based on determination of the wave propagation velocities in different directions. The second way exploits the spectral non-linearity between harmonic frequencies’ ratios and signal amplitude, which is an important parameter for defects’ detection in NDT (non-destructive testing). Both experimental data were statistically validated and the obtained results are promising for further use in the field of research and industry