Health monitoring of carbon/carbon, woven reinforced composites: Damage assessment by using advanced signal processing techniques. Part II: Acousto–ultrasonics monitoring of damage development

In the second part of this work, the acousto–ultrasonics waveforms acquired during the tests described in part I are processed using wavelet-based techniques in order to extract parameters capable of monitoring the damage accumulation in the C/C test coupons. A 10 level decomposition using the discrete wavelet transform is applied upon each one of the acquired acousto–ultrasonics waveforms. The continuous wavelet transform was also used and the wavelet grey moment was calculated for each waveform. Some of the parameters extracted from the wavelet-based analysis show an interesting monotonic variation and thus can be used as potential candidates for monitoring the damage development in the tested materials.