Failure Prediction in Structural Ceramics Using Acoustic Emission

Crack propagation in a typical structural ceramic (porcelain) is accompanied by acoustic emission. Two types of emission are detected. The first type is caused by slow growth of the fracture‐initiating flaw; the emission rate depends primarily on crack velocity. Failure prediction using this source of emission can be effective, however, only if low‐level emission, which may be related exclusively to crack growth, can be detected. The second source of emission, which occurs during bulk stressing, is the cracking associated with second‐phase particles (quartz particles in porcelain) as a result of the combined action of the applied stress and local thermal and mechanical stresses. An analysis for predicting emission rates is developed and forms the basis for using this source of acoustic emission in failure prediction.