Novel technique of NDE in ceramic bearing balls

A new technique for the nondestructive evaluation (NDE) of ceramic bearing balls is presented. The technique is based on measuring the quality factor (𝒬) of various surface waves. Thus, the existence of surface cracks will lower the surface wave resonance 𝒬´s. A simple experimental set-up capable of exciting and detecting the various resonances on the bearing balls and their 𝒬´s was constructed. Low-frequency resonances of torsional and spheroidal modes are used to measure the shear wave velocity V_s and Poisson´s ratio ν. High-frequency resonances of the surface waves are used to determine the presence of surface defects