Comparison of composite material degradation assesment methods using acoustic analysis and laser vibrometry

Assessment of degradation rate of material can be carried out by many experimental techniques differing in complexity and sophistication. A relatively simple method based on acoustic analysis is described in this contribution. Degradation of material’s properties due to fatigue loading is detectable in decrease of their modulus of elasticity that can be derived from natural frequencies of specimens. These measurements utilize self-designed device capable of specimen excitation and acquisition of its vibration. The recorded signal is then processed by spectral analysis enabling determination of natural frequencies. Usefulness of the above mentioned acoustic method can be seen in the fact that the measured changes of material’s parameters are comparable to those obtained by laser vibrometry, which is by several orders more expensive technique