Investigation on the influence of the equivalent bending stiffness of the thin-walled parts on the machining deformation

2018 ◽  
Vol 101 (5-8) ◽  
pp. 1171-1182 ◽  
Author(s):  
Bianhong Li ◽  
Hanjun Gao ◽  
Hongbin Deng ◽  
Hai Pan ◽  
Baoguo Wang
Keyword(s):  
Bending Stiffness ◽  
Machining Deformation ◽  
Equivalent Bending Stiffness ◽  
Thin Walled

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

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.

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

2021 ◽  
Vol 60 (1) ◽  
pp. 631-642
Author(s):  
Yan Xu ◽  
Zhongjun Shi ◽  
Bianhong Li ◽  
Zhang Zhang
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Dimensional Stability ◽  
Stress Relief ◽  
Bending Stiffness ◽  
Machining Process ◽  
7075 Aluminum Alloy ◽  
Maximum Deformation ◽  
Equivalent Bending Stiffness ◽  
Thin Walled

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.

Study on Machining Deformation Errors in Spiral Finish Milling of Thin-Walled Blades

2011 ◽  
Vol 314-316 ◽  
pp. 1773-1777
Author(s):  
Wei Wei Liu ◽  
Pei Chen ◽  
Xiao Juan Gao ◽  
Chen Wei Shan ◽  
Min Wan
Keyword(s):  
Geometric Dimension ◽  
Beam Theory ◽  
Milling Process ◽  
Simplified Model ◽  
Machining Deformation ◽  
Proposed Model ◽  
Thin Walled ◽  
The Relationship ◽  
Torsion Deformation

In this paper, a new procedure is proposed to study the deformation errors for spiral milling process of blade, which can be simplified as a stepwise beam based on the geometry and clamping characteristics. Kirchhoff beam theory is adopted to analyze the bending and torsion deformation. The relationship between machining deformation errors and the workpiece’s geometric dimension are also established based on the simplified model. Corresponding algorithms are realized by MATLAB codes. Experiment test shows that the results predicted by the proposed model are in well agreement with measured ones.

Bending of Pretwisted Beams

1955 ◽  
Vol 22 (3) ◽  
pp. 348-352
Author(s):  
J. Zickel
Keyword(s):  
General Theory ◽  
Bending Stiffness ◽  
Thin Strip ◽  
Principal Directions ◽  
Thin Walled ◽  
Lateral Deflections

Abstract The general theory of pretwisted beams and columns is applied to the bending of an initially straight and uniformly pretwisted beam of doubly symmetric thin-walled section. Pretwisting brings planes of various bending stiffness into play with a resulting stiffness which in a sense averages the stiffness of the beam in its principal directions. It is shown that compared with bending of an untwisted beam in its most flexible direction a thin strip can have its deflection in the plane of bending reduced 72 per cent by an initial twist of 0.83π. Simultaneously, however, lateral deflections of almost equal magnitude are induced. For pretwists above 2π, the lateral deflections become practically negligible and the deflections in the plane of bending are still reduced as much as 44 per cent. With increasing initial twist, however, the pretwisted beam becomes more flexible, and for an initial twist of 6.5π it is as flexible as the untwisted beam in its most flexible direction. Beams of equal flexibility in all directions simply become more flexible with initial twist, a fact which corresponds to the observations made by Den Hartog in some of his experiments.

Three-Dimensional Finite Element Simulation Analysis of Cutting Force of SiCp/Al Composite Thin-Walled Parts

2013 ◽  
Vol 589-590 ◽  
pp. 106-110 ◽  
Author(s):  
Yu Nan Liu ◽  
Shu Tao Huang ◽  
Li Zhou ◽  
Li Fu Xu
Keyword(s):  
Finite Element ◽  
Cutting Force ◽  
Simulation Analysis ◽  
Three Dimensional ◽  
Depth Of Cut ◽  
Milling Force ◽  
Machining Deformation ◽  
Al Composite ◽  
Radial Depth ◽  
Thin Walled

In milling process, cutting force is the main cause of machining deformation, and in machining of thin-walled parts, machining deformation is the major factor for machining error. In this paper, through finite element analysis software ABAQUS, three-dimensional simulation analysis on the machining of SiCp/Al composite thin-walled parts with a polycrystalline diamond tool have been carried out. It reveals the influence of radial depth of cut, cutting speed, and feed per tooth on cutting force. Analysis results show that: higher speed, small radial depth of cut and moderate feed per tooth can effectively reduce cutting force and inhibit deformation. In addition, a comparison is made between analysis results of milling force and high accuracy milling force prediction model, results from the two methods are similar.

Analysis of 45 Steel Rectangular Thin-Walled Parts Milling Deformation

2015 ◽  
Vol 667 ◽  
pp. 22-28 ◽  
Author(s):  
Jing Li ◽  
Zhan Li Wang ◽  
Ping Xi ◽  
Yang Jiao
Keyword(s):  
Prediction Model ◽  
Three Dimensional ◽  
Material Model ◽  
Machining Accuracy ◽  
Machining Deformation ◽  
Dimensional Finite Element ◽  
Prediction And Control ◽  
Length Direction ◽  
Thin Walled ◽  
Three Dimensional Finite Element

Aiming at the problem that the machining accuracy of 45 steel rectangular thin-walled parts are difficult to ensure because of poor rigidity, poor manufacturability and easy machining deformation, it used the three-dimensional finite element method, determined the material model of 45 steel and established a prediction model of 45 steel rectangular thin-walled parts milling deformation. The prediction results display that the deformation of the workpiece shows obvious parabola in length direction and a linear decreasing trend in width direction. It verifies the correctness of the prediction model through milling experiments and provides the method and basis for the prediction and control of machining deformation of 45 steel thin-walled parts.

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