ACOUSTIC-EMISSION AND NONDESTRUCTIVE EVALUATION OF BIOMATERIALS AND TISSUES

Acoustic emission (AE) is an acoustic wave generated by the release of energy from localized sources in a material subjected to an externall y applied stimulus. This technique may be used nondestructively to ana lyze tissues, materials, and biomaterial/tissue interfaces. Applicatio ns of AE include use as an early warning tool for detecting tissue and material defects and incipient failure, monitoring damage progression , predicting failure, characterizing failure mechanisms, and serving a s a tool to aid in understanding material properties and structure-fun ction relations. All these applications may be performed in real time. This review discusses general principles of AE monitoring and the use of the technique in 3 areas of importance to biomedical engineering: (1) analysis of biomaterials, (2) analysis of tissues, and (3) analysi s of tissue/biomaterial interfaces. Focus in these areas is on detecti on sensitivity, methods of signal analysis in both the time and freque ncy domains, the relationship between acoustic signals and microstruct ural phenomena, and the uses of the technique in establishing a relati onship between signals and failure mechanisms.