依据声弹性理论中超声波传播速度与材料内部应力的关系，提出采用超声横波和纵波联合的方式，使用横纵波一体化探头对已紧固发动机螺栓轴向应力进行测量的方法。对不同材料螺栓在高载荷时的栓体轴向应力测量系数进行研究，给出了螺栓材料系数的标定方法。主要对发动机缸体和轴承高强度螺栓在加载到140 kN左右时的测量结果进行了分析，实测结果显示应力超声测量的误差小于5 kN。

According to the relationship between the ultrasonic velocity and the internal stress of the material in the theory of acoustic elasticity, a method of measuring the axial stress of the fastening engine bolt by using the integrated longitudinal and transverse wave probe is proposed. The measurement coefficient of axial stress of bolts with different materials under high load is studied and the calibration method of bolt material coefficient is given. This paper mainly analyzes the measurement results of engine cylinder block and bearing high strength bolts during loading to about 140 kN. The experimental results show that the error range of ultrasonic stress measurement is within 5 kN.