Research On The Residual Stress For Laser Shot Peening On The Damaged Aircraft Components Based On Online Repairing

In the process of service time,there would be lots of corrosion damage in aircraft structural components which were worked in poor conditions.Surface strengthening technical was usually used to repair the damaged aircraft components.Because of these characteristics of flexible,controllable and effective,laser shot peening had wide application prospects in aircraft repairing.At the same time,laser shot peening is very suitable for online repairing,which can decrease the repairing cost and reparing cycle.Laser shot peening can induce compressive residual stresses on the impacted area of the material which are beneficial for the material.There are lots of connections between compressive residual stresses and the fatigue life of the damaged aircraft components.So,it is very necessary to research on the residual stress for laser shot peening on the damaged aircraft components based on online repairing.In this paper,7075-T6 aluminium alloy aircraft components with corrosion damage were selected as the research object,a integrated method of combining theoretical analysis,numerical simulation and experiment study were used to research the distribution of residual stress.The discipline of residual stress distribution under different laser shot peening parameters and geometrical features were obtained,and the experiments were carried out to verify the simulation results.According to the research needs of this paper,a single point with upright shot model,a single point with diagonal shot model and multipoint with upright shot model were establishd.Based on the geometrical features of damaged aircraft parts which had been polished,multipoint shot with complex geometrical features model were establishd.Set the time when the internal energy tends to be stable and the kinetic energy tends to zero as the solution time.Applied the load with spatial distribution by creating many local coordinate system,and according to set some boundary conditions,the finite element model of laser shot peening had been establishd,which provided a powerful technical support for the study of the discipline of residual stress distribution with different laser shot peening parameters and geometrical features.Based on the finite element model previously established,laser shot peening was simulated under different peak pressure,shot times,the sizes of the beam spot,overlapping rates and incidence angles.According to analysis the simulation results,the discipline of residual stress distribution with different laser shot peening parameters is acquired.The simulation of laser shot peening were carried out by FE simulation software ABAQUS under different surface shape and surface curvature.The results of numerical simulation indicates that the surface residual compressive stress range from high to low was biconcave surface,concave surface,male and female surface,plane,convex surface,biconvex surface.For biconcave surface,concave surface,male and female surface,the surface residual compressive stress increases with the increases of surface curvature,on the contrary,for convex surface,biconvex surface,the surface residual compressive stress decreases with the increases of surface curvature.It is very easily to be the intensity weak region for convex surface and biconvex surface after repairing.So,it is better to choose smaller surface curvature to polish these region.Using the Nd:YAG laser shot peening equipment to carry out the laser shot peening experiments,and measuring the residual stress of the specimen.Comparing the simulation results and experimental results,it shows that the maximum relative error is-9.55%,which indicates that the simulation results have high reliability...