Method for Determining Process Parameters of Laser Shot Peening Forming of Complicated Surface Shaped Workpieces

Abstract

The invention provides a method for determining the laser shot peening process parameters of complex curved surface shape workpieces, comprising the following steps: according to the curved surface parameter equation of the workpiece, the geometric characteristics of the curved surface of the workpiece are analyzed to calculate the principal strain direction, and then the laser beam is obtained. Laser pulse scanning direction in shot peening; establish a finite element model of workpiece bending deformation with the inherent strain distribution in the depth direction as the deformation source, and the inherent strain direction is the main strain direction. Through the optimization of the inherent strain field, the inherent strain along the depth direction at different positions of the workpiece is obtained distribution; according to the inherent strain response surface model under different laser shot peening process parameters and the inherent strain in the depth direction of different positions of the workpiece, the laser shot peening process parameters are optimized to obtain the best laser beam corresponding to the different inherent strain fields on the workpiece surface Shot peening process parameters. The invention can transform the inelastic deformation into the elastic deformation problem to improve the efficiency and accuracy of finite element simulation.

Description

technical field [0001] The invention relates to mechanical engineering technology, in particular to a method for determining technological parameters of laser shot-peening forming of workpieces with complex curved surfaces. Background technique [0002] The laser shot peening process has broad application prospects in the forming of complex curved surface workpieces of large structures such as aircraft wings, fuselages, and launch vehicle fuel tanks. Because the process uses laser as the energy source, the process parameters are highly controllable, which makes it easier to realize the precise forming of large workpieces. However, since the laser peening forming process is a moldless forming process, the forming of workpieces such as integral wall panels is realized by controlling the parameters and paths of laser peening on the forming surface. Since there is no definite mold to ensure the target shape is obtained, it brings great difficulties to the control of process par...

AI Technical Summary

Problems solved by technology

Since there is no determined mold to ensure the target shape is obtained, it brings great difficulties to the control of process parameters and shot blasting path

[0003] The invention with the application number 200510040116.9 discloses a method of laser peening forming of medium-thick plates. According to the curved surface shape of the processed parts, the required stress field distribution shape is simulated by the computer control system, and the shock wave pressure acting on the surface of the plate is optimized. And the distribution of shot peening trajectory, but this method does not pay attention to the root cause of surface deformation - inherent strain, does not provide a method for obtaining process parameters, and does not realize the optimization of process parameters. It is very difficult to form panels with complex curvatures; in addition , the invention of which the application number is 201310384814.5 discloses a digital shot peening method for integral wall panels. After analyzing the geometric information and material characteristics of the integral wall panels, the shot peening path and shot peening process parameters are determined. The selection of shot path and process parameters is completely based on geometric features, and the calculation efficiency and accuracy are difficult to meet the actual needs

[0004] To sum up, the determination of the process parameters in the existing laser shot peening process method relies too much on the geometric characteristics of the curved surface, without considering the essential characteristics that cause material deformation-intrinsic strain

Due to the complexity of the laser shot peening process, it is very difficult to manually adjust the parameters to achieve the same stress distribution as the target surface, and the forming accuracy of the surface with more complex shapes is not high

In addition, different process parameters can achieve the same deformation results, but there will be great differences in forming efficiency and energy consumption. The existing process methods ignore the problem of process parameter optimization

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