Research On Residual Stress Evolution And Deformation Behavior During Machining Of 7055 Aluminum Alloy Thick Plate

With the increasing demand for weight reduction and service life in the aerospace industry,the application of aluminum alloy structural components is becoming more and more widespread.However,due to its extremely high material removal ratio and complex thermal coupling relationship,the use of aluminum alloy structural components in machining processes can easily cause significant deformation,resulting in a substantial reduction in the yield rate of structural components and causing serious resource waste.This article uses a combined approach of finite element numerical simulation and experiments to study the influence of initial stress state and machining strategies on the deformation of 7055 aluminum alloy thick plates.The goal is to clarify the stress evolution and deformation behavior of aluminum alloy plates under different machining conditions and provide guidance for deformation control during the machining process.The main work and achievements include:The distribution law of residual stress inside the plate after asymmetric spraying was studied.After asymmetric spraying,the plate exhibited a typical stress state distribution of"external compression and internal tension".For plates sprayed asymmetrically along the thickness direction,the surface residual stress of the high spraying flow rate side was greater,and as the spraying intensity on the low spraying flow rate side decreased,the maximum stress in the core of the plate gradually shifted towards the high spraying flow rate side.For plates sprayed asymmetrically along the width direction,the surface stress level on the high spraying flow rate side was greater than that on the low spraying flow rate side.The stress level obtained from simulations was experimentally verified,and the results were in good agreement with the simulation results.The influence of the initial stress state on the deformation of the plate during machining was studied.The results showed that the initial stress state was a key factor affecting the deformation of the plate during machining.Under the same machining strategy,the larger the initial stress level,the greater the final machining deformation of the structural component For plates with stress levels asymmetric along the width direction,the maximum deformation at the bottom of the structural component after machining would shift towards the side with higher stress level.The influence of machining strategies on the deformation of the plate during machining was studied.The results showed that the flipping machining strategy had a significant impact on the deformation of the plate during machining.In the flipping machining strategy,as the amount of material removed from the top increased gradually,the deformation of the structural component showed a trend of decreasing first and then increasing,and the deformation form changed from "convex" to "concave".Compared with removing 10 mm of material from the top,the maximum machining deformation of the structural component decreased by 95%when only 3 mm of material was removed from the top.Different machining methods and sequences had a small influence on the machining deformation of the plate,with overall deformation differences within 5%.For plates with stress levels asymmetric along the thickness direction,the orientation of the frame had a significant impact on the machining deformation of the structural component,with the final machining deformation being smaller when the frame faced the side with higher stress level.The influence of the coupled initial stress state and machining strategy on the deformation of the plate during machining was studied.The results showed that under different machining strategies,the influence of the initial stress state on the deformation pattern of the structural component was relatively small,and the optimal machining strategy was basically the same under different initial stress states.The initial stress state significantly affected the machining deformation of the plate,with larger initial stress levels resulting in larger final deformation of the overall structural component.