Interface stiffness measurement of rough surface contact: A novel acoustic method based on robust reflection features

The in-situ structural health monitoring of interface stiffness is of great significance to the modeling of connection system and the revelation of interface evolution law. However, the highly sensitive reflection method for measuring ultrasonic interface stiffness relies on high excitation amplitude, and the mechanism of the interaction between contact nonlinearity and ultrasonic propagation has not been deeply explored. The existing interface stiffness measurement does not consider the randomness of boundary parameters, which limits the robustness of interface stiffness measurement. In this paper, we proposed a novel acoustic model without reference feature based on reflection mode (AMRR). A novel interface stiffness detection index is constructed to ensure the robustness of detection results. In order to verify the accuracy and robustness of the proposed model, the results are compared with those obtained by interface displacement method. The sensitivity of ultrasound signals under different excitation amplitudes was discussed and analyzed. The results showed that the proposed method has potential for in-situ detection of interface stiffness, which demonstrates the method’s potential engineering utility.