裂纹尖端超声散射场及动应力集中的动态光弹观测

超声波在裂纹尖端发生散射和动应力集中。深入研究裂纹尖端与超声波的相互作用是进行裂纹精确检测与评价的物理基础。在线性声学范畴内,裂纹尖端的散射场与弹性动力学的经典Lamb问题类似,而非线性响应更加复杂。利用动态光弹观测技术,可给出超声波在裂纹尖端散射过程的直观物理图像。无论是用于理论结果的实验验证,还是定量分析线性散射场和动应力集中现象,抑或深入探索非线性响应,动态光弹观测技术都可起到重要作用,因此,相关研究将促进检测声学与无损检测技术的发展。 

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.