A Method for Determining Intrinsic Strain of Laser Shot Peening Based on Computational Model

Abstract

The invention provides a method for determining the intrinsic strain of laser peening based on a calculation model, including performing laser peening single-point impact on materials, determining the time and space distribution model of laser impact pressure load, and establishing the continuous impact dynamics of laser peening The simulation model extracts the distribution model of the inherent strain along the depth direction in the two orthogonal directions of the plane and establishes a square plate calculation model based on this, and calculates the first bending deformation contour data of the square plate calculation model; laser shot peening scan is performed on the same material impacting, measuring and obtaining second bending deformation profile data; comparing the first bending deformation profile data with the second bending deformation profile data, and correcting the distribution model of the intrinsic strain along the depth direction in two orthogonal directions of the plane. The method provided by the invention has the characteristics of simplicity, accuracy and low cost, and can improve the accuracy of obtaining intrinsic strain.

Description

technical field [0001] The invention relates to the technical field of mechanical processing, in particular to a method for determining the intrinsic strain of laser shot peening based on a calculation model. Background technique [0002] Laser peening process is an emerging metal surface strengthening and plate forming technology. Compared with traditional mechanical shot peening, it has the outstanding characteristics of greater depth of plastic layer, stronger process controllability, and higher processing surface quality. Due to the above advantages, laser peening has broad application prospects in the engineering practice of aerospace and national defense, such as the aerodynamic shape forming of aircraft fuselage panels, the strengthening of aeroengine turbine blades, and the forming of launch vehicle fuel storage tanks. . [0003] The basic principle of laser peening is to cause plastic strain on the surface of the plate through laser shock, thereby introducing resid...

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Problems solved by technology

Although the inherent strain method has been widely used in the field of welding, it is still relatively scarce in the research of laser peening.

[0005] The existing patent "Method for Determining the Process Parameters of Laser Peening Forming of Complicated Curved Surface Shaped Workpieces" (application number CN201510102659.2) is the first in China to introduce the inherent strain method into the application of laser peening. According to the target surface shape optimization method to select the corresponding laser peening forming process parameters, but how to obtain the inherent strain distribution corresponding to different laser peening parameters is not introduced in this patent

In his paper, American scholar DeWald proposed a method of measuring the residual stress and establishing a semi-analytic formula to reverse the intrinsic strain. However, the implementation process of this method is complicated, and it is difficult to accurately measure the residual stress, and it is difficult to obtain the intrinsic strain in the depth direction.

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