Effects of TVSR process on the dimensional stability and residual stress of 7075 aluminum alloy parts

Abstract Residual stress generated during the blank forming and machining process significantly influences the dimensional stability of the mechanical parts. The equivalent bending stiffness and thermal vibration stress relief (TVSR) are two factors that affect the deformation of thin-walled workpiece. To increase the machining accuracy, on the one hand, increase the equivalent bending stiffness in manufacturing, and on the other hand, usually conduct the stress relief process to reduce the residual stress in manufacturing. In the present study, morphology optimization and TVSR process are conducted on a thin-walled part Specimen B of 7075 aluminum alloy to control the residual stress and machining deformation before finish machining. As a contrast, Specimen A is machined in one step. The deformations vary with time of Specimen A and B are measured. The corresponding finite element model is built to further study the stress and distortion during the machining process. Results showed that (1) deformation decreased with the increase of equivalent bending stiffness, compared with Specimen A, the maximum deformation of Specimen B decreased by 58.28%. (2) The final maximum deformation of Specimen B can be reduced by 38.33% by topology reinforcement to improve the equivalent stiffness and TVSR to reduce the residual stress.

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Effects of residual stress and equivalent bending stiffness on the dimensional stability of the thin-walled parts

The International Journal of Advanced Manufacturing Technology ◽

10.1007/s00170-021-08252-3 ◽

2022 ◽

Author(s):

Hanjun Gao ◽

Xin Li ◽

Qiong Wu ◽

Minghui Lin ◽

Yidu Zhang

Keyword(s):

Residual Stress ◽

Dimensional Stability ◽

Bending Stiffness ◽

Equivalent Bending Stiffness ◽

Thin Walled

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Effects of Residual Stress and Equivalent Bending Stiffness on the Dimensional Stability of the Thin-Walled Parts

10.21203/rs.3.rs-511993/v1 ◽

2021 ◽

Author(s):

Hanjun Gao ◽

Xin Li ◽

Qiong Wu ◽

Minghui Lin ◽

Yidu Zhang

Keyword(s):

Residual Stress ◽

Dimensional Stability ◽

Removal Rate ◽

Optimization Technique ◽

Bending Stiffness ◽

Topological Optimization ◽

Machining Deformation ◽

Equivalent Bending Stiffness ◽

Measuring Machine ◽

Thin Walled

Abstract The monolithic thin-walled parts are widely used in the aeronautic and astronautic field because of its excellent mechanical performance and light weight, but the thin-walled parts are vulnerable to the machining deformation due to its low stiffness and high material removal rate. According to the relative basic theory, the stiffness and internal residual stress of the part are the critical factors affecting the dimensional stability. In this work, the influences of equivalent bending stiffness and residual stress on the dimensional stability of thin-walled parts are studied. Nine typical thin-walled parts in three groups with two materials (7075 aluminum alloy for A1~A3 and B1~B3, and Ti6Al4V titanium alloy for B4~B6) are machined and treated with different processes. Topology optimization technique is used to optimize the structure of parts to enhance the bending stiffness. Corresponding finite element method (FEM) simulations are carried out to further investigate the generation mechanism. The deformations in 312 hours after machining are measured using coordinate measuring machine, and the deformation changes of the parts are obtained and analyzed. Finally, based on topological optimization and stress relief technology, a machining deformation control method for the monolithic thin-walled parts is proposed. Results show that the maximum and average deformations of thin-walled are evidently decreased using the proposed method.

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Finite Element Simulation Analysis on Residual Stress Relief of 7075 Aluminum Alloy Ring

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1032.135 ◽

2021 ◽

Vol 1032 ◽

pp. 135-140

Author(s):

Shao Feng Wu ◽

Xiang Sheng Gao ◽

Xian Rang Zhang ◽

Han Jun Gao

Keyword(s):

Residual Stress ◽

Aluminum Alloy ◽

Simulation Analysis ◽

Material Model ◽

Stress Relief ◽

Isotropic Hardening ◽

7075 Aluminum Alloy ◽

Vibration Stress ◽

Structural Parts ◽

Creep Constitutive Model

Vibration stress relief (VSR) and thermal stress relief (TSR) are important method to eliminate the residual stress of structural parts. The thermal vibratory stress relief (TVSR) is a new method to decrease and homogenize the residual stress. Based on the stress relaxation tests and the equivalent vibration equation of modal analysis, the creep constitutive model and the bilinear isotropic hardening plasticity material model (BISO) are combined to establish the numerical simulation model of TVSR of 7075 aluminum alloy ring part. The simulation results show that four different initial blank residual stress levels are obtained after quenching process, and the residual stress elimination and homogenization effect of TSR and TVSR is better than that of VSR. TVSR has a better effect on both residual stress elimination and homogenization, and the residual stress relief rate can reach more than 20%.

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Experimental Analysis and Prediction Model of Milling-Induced Residual Stress of Aeronautical Aluminum Alloys

Applied Sciences ◽

10.3390/app11135881 ◽

2021 ◽

Vol 11 (13) ◽

pp. 5881

Author(s):

Shouhua Yi ◽

Yunxin Wu ◽

Hai Gong ◽

Chenxi Peng ◽

Yongbiao He

Keyword(s):

Residual Stress ◽

Aluminum Alloy ◽

Prediction Model ◽

End Milling ◽

Orthogonal Experiment ◽

7075 Aluminum Alloy ◽

Side Milling ◽

Milling Parameters ◽

Thin Walled ◽

Machining Deformation Prediction

Aeronautical thin-walled frame workpieces are usually obtained by milling aluminum alloy plates. The residual stress within the workpiece has a significant influence on the deformation due to the relatively low rigidity of the workpiece. To accurately predict the milling-induced residual stress, this paper describes an orthogonal experiment for milling 7075 aluminum alloy plates. The milling-induced residual stress at different surface depths of the workpiece, without initial stress, is obtained. The influence of the milling parameters on the residual stress is revealed. The parameters include milling speed, feed per tooth, milling width, and cutting depth. The experimental results show that the residual stress depth in the workpiece surface is within 0.12 mm, and the residual stress depth of the end milling is slightly greater than that of the side milling. The calculation models of residual stress and milling parameters for two milling methods are formulated based on regression analysis, and the sensitivity coefficients of parameters to residual stress are calculated. The residual stress prediction model for milling 7075 aluminum alloy plates is proposed based on a back-propagation neural network and genetic algorithm. The findings suggest that the proposed model has a high accuracy, and the prediction error is between 0–14 MPa. It provides basic data for machining deformation prediction of aluminum alloy thin-walled workpieces, which has significant application potential.

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The Applications of Vibratory Stress Relief in High-Strength Aluminum Alloy Thick Plate

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.430-432.881 ◽

2012 ◽

Vol 430-432 ◽

pp. 881-885

Author(s):

Cai Jun Gan ◽

Kai Liao

Keyword(s):

Aluminum Alloy ◽

Residual Stresses ◽

Dimensional Stability ◽

Strain Energy ◽

Thick Plate ◽

High Strength ◽

Stress Relief ◽

High Strength Aluminum Alloy ◽

Mechanical Stretching ◽

Stretching Process

The level and distribution of residual stresses have great impact on dimensional stability, while Vibratory Stress Relief (VSR) is an effective technology to relax or homogenize residual stresses. Experimental study on residual stresses distribution, residual strain energy and machining deformation of 7075 high-strength aluminum alloy thick plate under different aging process status shows that VSR can effectively decrease the amplitude and strain energy density, and enhance stability of dislocation structures and phase states in metal microscopic volume, then internal residual stresses are homogenized to enhance components’ anti-deformation capacity. In addition, the capability in maintaining dimensional stability from VSR is better than that from traditional mechanical stretching process

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Effects of Cryogenic Treatment on the Microstructure and Residual Stress of 7075 Aluminum Alloy

Metals ◽

10.3390/met8040273 ◽

2018 ◽

Vol 8 (4) ◽

pp. 273

Author(s):

Lijun Wei ◽

Dawei Wang ◽

Haisheng Li ◽

Di Xie ◽

Fan Ye ◽

...

Keyword(s):

Residual Stress ◽

Aluminum Alloy ◽

Cryogenic Treatment ◽

7075 Aluminum Alloy

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Analysis and homogenization of residual stress in aerospace ring rolling process of 2219 aluminum alloy using thermal stress relief method

International Journal of Mechanical Sciences ◽

10.1016/j.ijmecsci.2019.04.040 ◽

2019 ◽

Vol 157-158 ◽

pp. 111-118 ◽

Cited By ~ 12

Author(s):

Qiong Wu ◽

Jian Wu ◽

Yi-Du Zhang ◽

Han-Jun Gao ◽

David Hui

Keyword(s):

Residual Stress ◽

Aluminum Alloy ◽

Thermal Stress ◽

Stress Relief ◽

Rolling Process ◽

Ring Rolling ◽

2219 Aluminum Alloy ◽

Ring Rolling Process

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Optimal Clamping Scheme of Thin-Walled Cavity Workpiece

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.189-193.2116 ◽

2011 ◽

Vol 189-193 ◽

pp. 2116-2120

Author(s):

Shi Min Geng ◽

Jun Wang

Keyword(s):

Finite Element ◽

Aluminum Alloy ◽

Machining Process ◽

Machining Accuracy ◽

Finite Element Models ◽

Thin Walled ◽

Clamping Sequence

The thin-walled cavity workpiece with insufficient rigid property is liable to deform during the machining process and the request of accuracy is very strict. The paper takes typical aeronautic aluminum-alloy for example, fixture is an important consideration in the operation. To reveal the influences of locating points, clamping sequence and loading ways on the distortion of thin-walled cavity part, finite element models were established to simulate the clamping operation. The result shows the preferable scheme is that the distance of the clamping locations are far each other, clamping forces are firstly applied on the surface with high rigid and all clamping forces are applied in many steps. The scheme can effectively control the deformation of clamp ,and furthermore improve the machining accuracy.

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Research on Vibration Stress Relief Based on FEM

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.42.35 ◽

2010 ◽

Vol 42 ◽

pp. 35-38

Author(s):

Chun Mei Li ◽

Feng Kui Cui

Keyword(s):

Residual Stress ◽

Finite Elements ◽

Stress Distribution ◽

Stress Relief ◽

Residual Stress Distribution ◽

Exciting Force ◽

Finite Elements Method ◽

Machining Process ◽

Exciting Frequency ◽

Vibration Stress

In order to improve VSR(Vibration Stress Relief) effect, finite elements method is applied to study VSR process factors. Simulation on moulding process, rough machining process and heat treatment are used to study the residual stress distribution of casting. The modal analysis is carried out to determine exciting frequency, exciting position and support position. Based on residual stress distribution, harmonic response analysis is applied to find relationship between dynamic stress and exciting force. Then the exciting force can be determined. The research results indicate that finite elements method can be used to determine VSR process parameters quickly and accurately.

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