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

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

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.

scholarly journals Improving accuracy of bulk residual stress characterization in ribbed geometries through equivalent bending stiffness

Procedia CIRP ◽  
2021 ◽  
Vol 102 ◽  
pp. 325-330
Author(s):  
Maria Aurrekoetxea ◽  
Iñigo Llanos ◽  
Oier Zelaieta ◽  
Luis Norberto Lopez de Lacalle
Keyword(s):  
Residual Stress ◽  
Bending Stiffness ◽  
Equivalent Bending Stiffness ◽  
Improving Accuracy

Analysis of circumferentially welded thin-walled cylinders to study the effects of tack weld orientations and joint root opening on residual stress fields

2009 ◽  
Vol 223 (5) ◽  
pp. 1037-1049 ◽  
Author(s):  
N U Dar ◽  
E M Qureshi ◽  
A M Malik ◽  
M M I Hammouda ◽  
R A Azeem
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Arc Welding ◽  
Operating Conditions ◽  
Stress Fields ◽  
Welded Structures ◽  
Prime Concern ◽  
Thin Walled ◽  
Tack Weld ◽  
Welding Processes

In recent years, the demand for resilient welded structures with excellent in-service load-bearing capacity has been growing rapidly. The operating conditions (thermal and/or structural loads) are becoming more stringent, putting immense pressure on welding engineers to secure excellent quality welded structures. The local, non-uniform heating and subsequent cooling during the welding processes cause complex thermal stress—strain fields to develop, which finally leads to residual stresses, distortions, and their adverse consequences. Residual stresses are of prime concern to industries producing weld-integrated structures around the globe because of their obvious potential to cause dimensional instability in welded structures, and contribute to premature fracture/failure along with significant reduction in fatigue strength and in-service performance of welded structures. Arc welding with single or multiple weld runs is an appropriate and cost-effective joining method to produce high-strength structures in these industries. Multi-field interaction in arc welding makes it a complex manufacturing process. A number of geometric and process parameters contribute significant stress levels in arc-welded structures. In the present analysis, parametric studies have been conducted for the effects of a critical geometric parameter (i.e. tack weld) on the corresponding residual stress fields in circumferentially welded thin-walled cylinders. Tack weld offers considerable resistance to the shrinkage, and the orientation and size of tacks can altogether alter stress patterns within the weldments. Hence, a critical analysis for the effects of tack weld orientation is desirable.

Analysis of circumferentially arc welded thin-walled cylinders to investigate the residual stress fields

2008 ◽  
Vol 46 (12) ◽  
pp. 1391-1401 ◽  
Author(s):  
Afzaal M. Malik ◽  
Ejaz M. Qureshi ◽  
Naeem Ullah Dar ◽  
Iqbal Khan
Keyword(s):  
Residual Stress ◽  
Stress Fields ◽  
Thin Walled

Uphill Quenching of Aluminum Alloys

2019 ◽  
Author(s):  
Wellington da Silva Mattos ◽  
George Edward Totten ◽  
Lauralice de Campos Franceschini Canale
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Residual Stress ◽  
Aluminum Alloys ◽  
Temperature Gradient ◽  
Dimensional Stability ◽  
Steam Chamber ◽  
Conventional Heat Treatment ◽  
Quenching Process ◽  
Uphill Quenching

This article describes the concept of uphill quenching process applied in the heat treatment of aluminum alloys. Uphill quenching is interesting since residual stress reductions of up to 80% has been reported. In addition, substantial improvements in dimensional stability have been achieved for several types of aluminum parts. Often, uphill quenching is applied after quenching and before aging during the heat treatment of aluminum alloys. The uphill quenching process consists of the immersion of the part in a cryogenic environment, and after homogenization of the temperature, the part is transferred to the hot steam chamber to obtain a temperature gradient that will maintain the mechanical properties gained with this process. The results obtained are lower residual stress and better dimensional stability. The aim of this article is to provide a review of this process and to compare it with conventional heat treatment.

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.

Investigation of redistribution mechanism of residual stress during multi-process milling of thin-walled parts

2019 ◽  
Vol 103 (1-4) ◽  
pp. 1459-1466
Author(s):  
Miaoxian Guo ◽  
Xiaohui Jiang ◽  
Yi Ye ◽  
Zishan Ding ◽  
Zhenya Zhang
Keyword(s):  
Residual Stress ◽  
Redistribution Mechanism ◽  
Thin Walled
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