# Effect of Plate Thickness on Residual Stress Distribution of GH3039 Superalloy Subjected to Laser Shock Peening

## TL;DR

This study examines how plate thickness affects residual stress in a superalloy after laser shock peening, using simulations and experiments.

## Contribution

A modified Johnson-Cook constitutive equation is proposed to accurately predict the mechanical behavior of GH3039 under ultra-high strain rates.

## Key findings

- The modified J-C equation accurately predicts residual stress fields in GH3039 alloy plates of different thicknesses.
- Residual stress distribution varies with plate thickness due to differences in bending stiffness and wave coupling effects.
- Simulated results align well with experimental measurements, validating the modified model.

## Abstract

To accurately assess the effect of different plate thicknesses on the residual stress field of laser shock peened GH3039 superalloy, residual stress measurements were performed on GH3039 alloy plates with thicknesses of 2 mm and 5 mm after laser shock peening (LSP) treatment. Both quasi-static and high strain rate mechanical tests of GH3039 were conducted, and the Johnson-Cook (J-C) constitutive equation for GH3039 alloy at specific strain rates was fitted based on the experimental results. To obtain the parameter C in the J-C constitutive equation of GH3039 alloy under ultra-high strain rates, a modified method was proposed based on LSP experiment and finite element simulation results. Using the modified GH3039 alloy J-C constitutive equation, numerical simulations and comparative analyses of the residual stress field of GH3039 alloy plates of different thicknesses under LSP were carried out using ABAQUS software. The simulated residual stress fields of laser-shocked GH3039 alloy plates of different thicknesses were in good agreement with the experimental measurements, indicating that the modified GH3039 alloy J-C constitutive equation can accurately predict the mechanical behavior of GH3039 alloy under ultra-high strain rates. Based on the modified GH3039 alloy J-C constitutive equation, the effect of different plate thicknesses on the residual stress distribution of laser-shocked GH3039 alloy was studied, along with the underlying mechanisms. The unique distribution characteristics of residual stresses in laser-shocked GH3039 plates with varying thicknesses are primarily attributed to differences in plate bending stiffness and the detrimental coupling effects of reflected tensile waves.