Nondestructive Crack Detection by High-Speed Digital Holographic Interferometry and Impact-Induced Traveling Waves

The mechanical behavior and performance of engineered components are severely affected by the nucleation of surface and internal cracks or voids that could potentially lead to detrimental mechanical failures. In this paper, progress on the development of a high-resolution nondestructive method for detection and quantification of micro-surface and subsurface defects is presented. The experimental process comprises the use of manufactured samples with engineered cracks stimulated by impact-induced surface traveling waves. Micro- to nanoscale distortions of the traveling wavefronts are quantified in full field-of-view (FOV) using high-speed digital holographic interferometry (DHI). The experimental results are compared and validated with laser Doppler vibrometer (LDV). We report the performance of the currently under development approach for detection and quantification of surface cracks found in engineered components using high-speed DHI.