Predicting AE attenuation in structures by geometric analysis

This paper investigates the feasibility of predicting the attenuation of AE signals travelling within a complex solid body. Such AE can occur due to external stimulation (e.g. impact) or internal events (i.e. crack propagation). The attenuation of these signals is affected not only by material properties but also by the geometry of the object. For example, wave propagation on a typical engine block is complex because of its intricate shape with variations and discontinuities in thickness and surface curvature. In contrast to much of the reported work in computer graphics (CG) literature that models the transmission of sound in rooms and buildings, this paper reports the development of a ray firing procedure to model the transmission of rays both across the surface and through the interior of a complex mechanical solid. The attenuation rate is proportional to the AE path length so the challenge of modelling the physical phenomena involves calculating the path lengths between the sensor and the source. The results of the computational simulation are compared with those obtained by experiment and found to be in good agreement.