Automatic Measurement of Contact Stress and Connection Force of Interference Components by Ultrasound

Tiny interference components play an important role in the aerospace and instrumentation fields. Contact stress and connection force are important factors in evaluating the reliability and service life of components. In this study, the ultrasonic method is used to measure the stress distribution and the connection force on the mating interface. Based on statistical microcontact theory, the virtual thin-layer model, and the asperity interaction model, the contact acoustic model is optimized. On this basis, the mapping relationship between contact stress and contact stiffness can be further obtained. This relationship was obtained by calibration experiments. Then, the stress distribution on the interface with two different structures, namely the uniform cylinder and the step cylinder, was measured and compared with the theoretical results of the thick-walled cylinder theory. The results show that the two have good consistency. Finally, based on the stress distribution, the connection force was calculated and compared with the experimental results. The results show that the ultrasonic measurement method can accurately measure the connection force, and the relative error is within 16%. Therefore, this study can provide a good method for the quality assessment of interference components.