基于声弹性理论，使用自主研发的基于压电传感器的激光超声场检测仪对Q235钢的表面应力与激光激发表面波速间的关系进行了研究，并与采用表面波压电探头测得的试验结果进行对比；采用该试验装置得到了铸铁制动盘表面应力与激光激发表面波速的关系，应用激光激发表面波法测得制动盘表面不同位置的残余应力，并与X射线应力法的测试结果进行了对比。结果表明：采用激光激发表面波法测得Q235钢的声弹性系数为1.02×10^-5 MPa^-1，与采用表面波压电探头测得的结果非常接近，测试精度较高；采用X射线应力法和激光激发表面波法测得的铸铁制动盘不同位置的残余应力均为压应力，应力大小不同但变化趋势一致。

The relationship between surface stress and laser-generated surface wave velocity of Q235 steel was studied by self-developed laser ultrasonic detector based on piezoelectric sensor with the help of the acoustoelasticity theory, and was compared with experiment results tested by surface wave piezoelectric probe. The relationship between surface stress and laser-generated surface wave velocity of cast iron brake disc was obtained by the detector. The residual stresses at different positions of the cast iron brake disc were detected by laser-generated surface wave technique and compared with that measured by X-ray stress analyzer. The results show that the acoustoelasticity coefficient of Q235 steel detected by laser-generated surface wave technique was 1.02×10^-5 MPa^-1, and was very close to that measured by surface wave piezoelectric probe. The stresses at different positions of the cast iron brake disc measured by laser-generated surface wave technique and X-ray stress technique were all compressive stress. The values of the stesses by the two techniques were different, but the stresses had the same trend.