| Nonlinear Ultrasonic Testing Method |
| function Summary |
| By utilizing the nonlinear coefficients tested by nonlinear ultrasonic to characterize the fatigue damage of metal components such as micro plastic deformation, micro cracks and residual stress etc. Through the relationship between nonlinear coefficient and stress, the residual stress can be measured quantitatively. |
| Technical features |
Non-contact measurement for residual stress |
| Continuously rapid detection in robotic non-destructive testing system |
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| Block Diagram and Real System of Nonlinear Ultrasonic Testing System |
| Technical principle |
| RITEC high power ultrasonic transceiver system generates excitation signal to drive the surface wave transducer which center frequency is f, then an acoustic signal is generated in metal specimen. In order to highlight the harmonic amplitude of received signal, a surface wave receiving transducer which center frequency is 2f is used and the received signal waveform is transformed by FFT. Then measure the fundamental amplitude A1 and higher harmonic amplitude A2, A3 to determine the second order relative nonlinear coefficient β' and the third order relative nonlinear coefficient δ'. |
| Where A1, A2, A3 is the fundamental amplitude, the second-harmonic amplitude and third-harmonic amplitude of received signal, respectively. |
| Applications |
| By using the nonlinear ultrasonic method for welding aluminum plate residual stress measurement, by using the manipulator to realize water coupling scanning automatically and the automatic, non-contact, rapid nondestructive testing. |
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| The water coupling nonlinear ultrasonic testing |
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| The air coupling nonlinear ultrasonic testing |
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