基于光栅式激光超声声谱的残余应变测量方法研究  

The residual strain measurement based on laser grating ultrasonic spectrum

作　　者：寇兴 张亚平[2] 裴翠祥[1] 钟志民[2] 陈振茂[1] Kou Xing;Zhang Yaping;Pei Cuixiang;Zhong Zhimin;Chen Zhenmao(Shaanxi Engineering Research Center of NDT and Structural Integrity Evaluation,State Key Laboratory for Strength and Vibration of Mechanical Structures,Xi'an Jiaotong University,710049,Xi'an,China;Department of Equipment and Maintenance,State Nuclear Power Plant Service Co.Ltd.,200233,Shanghai,China)

机构地区：[1]西安交通大学航天航空学院机械结构强度与振动国家重点实验室陕西省无损检测与结构完整性评价工程技术研究中心,西安710049 [2]国核电站运行服务技术有限公司设备与维修业务部,上海200233

出　　处：《应用力学学报》2021年第5期1877-1883,共7页Chinese Journal of Applied Mechanics

基　　金：国家重大专项大型先进压水堆及高温气冷堆核电站项目(2018ZX06002008);国家自然科学基金(12072255)。

摘　　要：提出了一种基于光栅激光超声进行残余应变测量的新型非接触超声检测方法。该方法利用光栅激光源激发具有特定波长的窄频带的相干表面波,通过测量表面波声谱的变化实现残余应变的测量。建立了考虑声弹效应的激光超声有限元模型,模拟了光栅激光超声在施加了预应变的介质中产生的相干表面波,研究了表面波中心频率与材料表面残余应变之间的变化关系,考察了该方法的检测能力。模拟结果表明,光栅激光超声产生的表面波(SW)波速与应变的大小呈线性关系;当应变场深度小于波长(0.05mm)时,表面波的中心频率有明显的下降,之后逐渐趋于平缓。最后,利用拉伸试验得到的具有不同残余塑性应变的试件进行实验测试,验证了基于光栅激光超声的残余应变测量方法的有效性。测量结果表明,相干表面波的波速与塑性应变呈线性关系。In this paper,a novel noncontact ultrasonic testing method based on laser grating is proposed for residual strain measurement.In this method,the laser grating technique is utilized to generate coherent surface waves with a specific wavelength in narrow frequency bandwidth.A numerical method based on finite element model is established to simulate the coherent surface waves generated by the laser grating in pre-strained media to determine the capability and sensitivity of this method.The relationship between the strain and frequency spectrum of the coherent surface wave is studied.Finally,an experiment validation of the laser grating based UT of residual strain is carried out with using specimen with different plastic strain by tensile test.

关 键 词：残余应变 超声检测 光栅激光超声 超声声谱 

分 类 号：TB559[理学—物理]