描述:
In this study, we apply the noncollinear shear wave mixing technique to detect and visualize fatigue damage in aerospace titanium alloy components that are invisible to conventional methods. This technique exploits the nonlinear interaction between two columns of shear waves and fatigue damage in titanium alloy components, which generates a sum-frequency longitudinal wave. By adjusting the relative position and separation distance of the excitation transducers and the receiving transducer in the nonlinear mixing system, we can effectively control the mixing beam in the horizontal/vertical direction of the detection position. We test the nonlinear characteristics of 63 detection points near the fatigue crack. The experimental results show that the mixing nonlinear coefficient exhibits a “step” trend when the fatigue crack is inside the titanium alloy, and the “step” width increases with the crack length. The distribution of the mixing nonlinear coefficient can be used to effectively characterize the length of invisible fatigue crack in the vertical direction. Moreover, we can visualize the fatigue damage area near the invisible fatigue crack inside the metal component by using the contour map of the normalized mixing nonlinear coefficient of 63 detection points near the fatigue crack.
描述:
In this study, we apply the noncollinear shear wave mixing technique to detect and visualize fatigue damage in aerospace titanium alloy components that are invisible to conventional methods. This technique exploits the nonlinear interaction between two columns of shear waves and fatigue damage in titanium alloy components, which generates a sum-frequency longitudinal wave. By adjusting the relative position and separation distance of the excitation transducers and the receiving transducer in the nonlinear mixing system, we can effectively control the mixing beam in the horizontal/vertical direction of the detection position. We test the nonlinear characteristics of 63 detection points near the fatigue crack. The experimental results show that the mixing nonlinear coefficient exhibits a “step” trend when the fatigue crack is inside the titanium alloy, and the “step” width increases with the crack length. The distribution of the mixing nonlinear coefficient can be used to effectively characterize the length of invisible fatigue crack in the vertical direction. Moreover, we can visualize the fatigue damage area near the invisible fatigue crack inside the metal component by using the contour map of the normalized mixing nonlinear coefficient of 63 detection points near the fatigue crack.