A Research Initiation Award will fund a study of advanced nondestructive testing of structural materials by acoustic emission. A combination of model development and experimental validation will be used. The model will use an acoustic signal source which is an actual crack propagation and arrest event and which includes crack location and orientation, crack tip velocity and duration of propagation, component geometry, and mode of fracture. The dynamic stresses will be calculated at each point by the integral method. From the stresses the local dynamic displacements will be calculated and used to determine the expected acoustic emission signal waveform.