三维残余应力场超声无损检测原理和方法

The accurate measurement of the residual stress profile is the effective characterization of the different distribution of residual stress. The phenomenon of residual stress and its uneven distribution exist inevitably in high temperature and high pressure container, oil and gas pipelines, aircrafts, aerospace and other large equipments and products. Therefore, the accurate assessment and judgment of residual stress is very important for the stability and reliability of the components and large equipment. This project is based on acousto-elastic mechanism and ultrasonic nondestructive testing technology and combined with one-dimensional stress and two-dimensional stress field theory. It carrys out in-depth study on ultrasonic nondestructive testing principles and methods of 3D residual stress field and find out the stress distribution rule of residual stress in the depth direction. It's also explores the dissemination and mechanism of action of ultrasonic in residual stress component. And furthermore, it looks for the ultrasonic characterization theory of 3D residual stress vector field and sets up the ultrasonic testing method of 3D residual stress field, thus solving the scientific problems of ultrasonic nondestructive testing mechanism and ultrasound 3D characterization method of the residual stress field. By researching the ultrasonic nondestructive testing principles and methods of 3D residual stress and clearing the status of residual stress in each part of the component, the accurate judgment and evaluation for the sizes and distribution of residual stresses have very important theoretical research value and requirements of engineering applications.

残余应力场的准确测量是对不同分布的残余应力的有效表征。在高温高压容器、石油天然气管道、飞机、航空航天等大型装备和产品中，不可避免存在着残余应力以及残余应力分布的不均匀现象。因此，对残余应力准确评估和判断直接影响到构件及大型装备的稳定性和可靠性。本项目基于声弹性机理及超声无损检测技术，结合一维应力和二维应力场理论，开展对三维残余应力场超声无损检测原理和方法的深入研究，找出残余应力在深度方向应力分布规律，探索超声波在残余应力构件内的传播及作用机理，寻找三维残余应力矢量场的超声法表征理论，建立三维残余应力场的超声检测方法，从而解决残余应力场超声无损检测机理及残余应力场超声三维表征方法的科学问题。通过对三维残余应力的超声无损检测原理和方法的研究，明确构件各部位的残余应力状态，对残余应力大小及分布的准确判断和评估具有十分重要的理论研究价值和工程应用需求。

随着社会工业化程度的不断提高，天然气输送管线的泄漏、发动机叶片的疲劳损伤、军车传动轴的断裂等安全隐患对国家财产和人民生活造成巨大的危害，构件内部残余应力分布不均匀是导致这些有害现象出现的一个非常重要的影响因素，所以对这些构件内部残余应力状态进行准确测量及表征技术的研究是十分必要的。本项目基于声弹性原理及超声无损检测技术，结合一维和二维应力场理论，开展了对三维残余应力场超声无损检测原理和方法的深入研究。提出了运用不同频率的临界折射纵波来检测构件不同深度残余应力分布状态，找出了残余应力在深度方向应力分布规律，探索了超声波在残余应力构件内的传播及作用机理，寻找了三维残余应力矢量场的超声法表征理论。通过横纵波结合的方法和不同频率临界折射纵波检测深度不同建立了三维残余应力场的超声检测方法，从而解决了残余应力场超声无损检测机理及残余应力场超声三维表征方法的科学问题。最后，通过实验来验证运用不同频率临界折射纵波检测构件不同深度残余应力分布的可行性，然后运用变频法对厚壁管的应力梯度进行检测。对三维残余应力的超声无损检测原理和方法的研究，明确构件各部位的残余应力状态，对残余应力大小及分布的准确判断和评估具有十分重要的理论研究价值和工程应用需求。