Measurement method of bolt hole assembly stress based on the combination of ultrasonic longitudinal and transverse waves

Abstract

Accurate measurement of the assembly stress of the aero-engine rotor bolt hole is of great significance for improving the assembly quality and safety of the aero-engine. The bolt hole is covered by the nut and the bolt's head so that the assembly stress cannot be directly and effectively measured. Aiming at this problem, this paper uses the ultrasonic method to measure the assembly stress of bolt holes based on the principle of wave mode conversion and acoustoelastic effect. On the basis of analyzing the influence of stress on the propagation velocity of longitudinal and transverse waves, an assembly stress measurement model for bolt holes based on the combination of longitudinal and transverse waves is established. The reflected signal of the bolt hole wall is analyzed by the finite element calculation software. The experimental results show that the method based on the combination of ultrasonic longitudinal and transverse waves realized the bolt hole assembly stress measurement. The average measurement error and average relative error of this method are 2.230 MPa and 5.456%, respectively. This study provides a promising method for accurately measuring the assembly stress of the aero-engine rotor bolt hole.