Photoelastic visualization and measurement of ultrasonic scattering fields and dynamic stress concentrations at crack tips

Ultrasonic scatterings and dynamic stress concentrations occur at crack tips. The quantitative measurement and evaluation of cracks rely on the physical interaction of ultrasonic wave and the crack tip. In the scope of linear theory, ultrasonic scattering field at the crack tip is similar to the Lamb problem in elastic dynamics, while the nonlinear response is much more complicated. Dynamic photoelastic technique plays an important role in theoretical results verification and quantitatively experimental research on both the linear and nonlinear ultrasonic scatterings and dynamic stress concentrations through photoelastic images or videos captured by a state-of-the-art system. As a result, it will promote the development of ultrasonic research and nondestructive testing techniques.