Residual stress measurement method based on femtosecond laser processing

Abstract

A residual stress measuring method based on femtosecond laser processing comprises the following steps: firstly, arranging a measuring system for femtosecond laser processing, and then polishing a to-be-measured part of a sample piece; smearing an adhesive on the bottom surface of a strain gauge, scraping, aligning to a to-be-measured part of the sample piece, and flatly placing the bottom surfaceof the strain gauge on the sample piece downwards; aligning a round hole in the middle of a wiring terminal with the bonded strain gauge, horizontally placing the wiring terminal on a sample piece, and respectively connecting a strain gauge lead and a test lead to the corresponding wiring terminal; respectively connecting the strain gauge and a compensation gauge to the ports of the strain gauge;checking the insulation degree and resistance change condition of the strain gauge and the sample piece, setting corresponding parameters of a laser, and then focusing femtosecond laser pulses to theto-be-measured surface of the sample piece for processing to obtain a line; and measuring strain value data released by the corresponding processing area, and calculating residual stress. According to the invention, the ultrashort pulse femtosecond laser is innovatively applied to process the material, so that the heat affected zone is reduced from hundreds of microns to several microns, and theprocessing precision is extremely high.

Description

technical field [0001] The invention relates to the technical field of optical design, in particular to a method for measuring residual stress based on femtosecond laser processing. Background technique [0002] Residual stress exists in almost all materials, which will cause problems such as cracking and deformation of materials in the actual production process. Residual stress may be the main factor leading to material failure. Therefore, it is very important to effectively measure the residual stress in materials. [0003] The traditional machining measurement method will generate additional additional mechanical stress due to the direct contact between the equipment and the sample. This additional stress has great uncertainty and affects the measurement accuracy of residual stress. At the same time, traditional mechanical processing will also produce thermal effects, which will affect the performance of materials on the one hand and generate additional thermal stress on...

AI Technical Summary

Problems solved by technology

[0003] The traditional mechanical processing measurement method will generate additional additional mechanical stress due to the direct contact between the equipment and the sample. This additional stress has great uncertainty and affects the measurement accuracy of residual stress.

At the same time, traditional mechanical processing will also produce thermal effects, which will affect the performance of the material on the one hand, and will also generate additional thermal stress on the other hand.

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