Resonance acoustic spectroscopy of lossy materials

Abstract

Resonance acoustic spectroscopy (RAS) is known as an efficient tool for determining the elastic and dissipative parameters of materials. However, its use for diagnostics of a variety of materials with a low quality factor (including materials with defects) is often impeded by overlapping of resonance responses at different modes. Here, a method of processing experimental data is suggested which enables one to determine resonance frequencies and Q-factors in cases of broad and overlapping resonances. In experiments, both undamaged and cracked samples were studied. A swept-frequency excitation was used for polycarbonate samples, whereas an impulse method with impact excitation was used for concrete samples. Signal processing was performed with the use of the suggested algorithm. In particular, the decrease of the Q-factor and splitting of resonance frequencies due to crack formation were registered. This method, which demonstrates a high efficiency even at a significant resonance overlapping, can be used for nondestructive testing of a broad class of materials.