Method for testing multiple welding residual stress components via three-dimensional optical contour method

Abstract

The invention relates to a method for testing multiple welding residual stress components via a three-dimensional optical contour method. Pretreatment is carried out before welding; and after welding, a low speed wire is used to cut a tested plate for multiple time, the primary cutting direction is vertical to the weld seam direction of the test plate, and cutting is carried out along the middle cross section. XJTU-OM scanning is carried out on cutting planes of the test plate, and calculated measurement point cloud data is obtained; and an established data processing platform is used to carry out positive conversion, de-noising, displacement calculating, discretion, and boundary condition output on the point cloud data. The stress is calculated and analyzed to obtain vertical residual stress distribution of primary cutting. The secondary cutting direction is vertical to the first cutting direction and along the middle cross section, the same scanning and data processing are carried out on the cutting surface contour after secondary cutting, the stress is calculated by taking the secondary cutting plane contour data as boundary conditions, and stress elasticity calculation of the secondary cutting plane is realized. Thus, the method has theoretical and engineering significance in testing the multiple residual stress components of a welding member.

Description

technical field [0001] The invention relates to the technical field of engineering measurement residual stress, in particular to a method for testing multiple welding residual stress components by three-dimensional optical profilometry. Background technique [0002] Since the development of residual stress testing, there have been dozens of testing methods for different working conditions, which are divided into mechanical (destructive) measurement methods and physical (non-destructive) measurement methods, each of which has its own advantages and disadvantages. Destructive methods include blind hole method, strip cutting method, elastic deformation method, etc. Among them, the small hole method is used more. The small hole release method is suitable for measuring welded components with large stress gradient changes due to its simple operation, and it is also suitable for measuring The advantages of small destructive components have been widely used in recent years, and it h...

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Problems solved by technology

However, both of these two commonly used methods measure the surface residual stress and cannot measure the internal residual stress of the workpiece.

Other internal residual stress testing methods, such as the layer-by-layer peeling method and the crack flexibility method, can measure the uniform residual stress distribution state of thick plates, but for welding residual stress fields with large stress gradient changes, they cannot accurately measure longitudinal stress and Transverse stress gradient, and complex and cumbersome, while the neutron diffraction method is too costly, time-consuming and limited to large-scale components

The contour method can only obtain the normal stress of the cut surface in a single cutting process, but the welding stress problem of thick plates often involves residual stress in multiple directions

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