Acoustic Emission (AE) has been studied as a nondestructive testing method for real time damage detection and location studies. The method relies on the propagation of the elastic waves due to the formation of new crack faces. While the method is capable of detecting damage initiation and location with an array of sensors, the variations in geometries and material properties, which change the output response, limit the capabilities of the method in further quantifications in terms of damage size and orientation. The ability to accurately model elastic waves offers significant potential for understanding the AE data; however, the oscillatory nature of wave equation requires very fine meshing and small time step for a stable numerical solution. In this paper, the AE signature of the damage initiation is predetermined using effective numerical models. The numerical model reduces the required degrees of freedom about 60% as compared to conventional finite element formulation and the computational time. Through studying different geometries and materials, it is demonstrated that the crack size and orientation can be identified if the magnitude and the phase of the surface motion are preserved without any modifications due to data acquisition electronics. When the AE sensors are positioned properly, the phase difference of two sensors indicates the crack orientation and direction. The numerical results are validated on monotonic testing of aluminum coupon samples with induced notches at different angles. Understanding the crack orientation provides the directions of the acoustic wave patterns, which improves the source location accuracy with proper wave velocity selection.

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