Wrinkling Limit in Tube Bending

2000 ◽  
Vol 123 (4) ◽  
pp. 430-435 ◽  
Author(s):  
Xi Wang ◽  
Jian Cao
Keyword(s):  
Material Properties ◽  
Deformation Theory ◽  
Energy Approach ◽  
Tube Bending ◽  
Predictive Tool ◽  
Bending Process ◽  
Thin Walled Tube ◽  
Bending Radius ◽  
Thin Walled ◽  
Doubly Curved

Thin-walled tube bending has found many of its applications in the automobile and aerospace industries. This paper presents an energy approach to provide the minimum bending radius, which does not yield wrinkling in the bending process, as a function of tube and tooling geometry and material properties. A doubly-curved sheet model is established following the deformation theory. This approach provides a predictive tool in designing/optimizing the tooling parameters in tube bending.

Wrinkling Limit in Tube Bending

2000 ◽  
Author(s):  
Xi Wang ◽  
Jian Cao
Keyword(s):  
Material Properties ◽  
Deformation Theory ◽  
Energy Approach ◽  
Tube Bending ◽  
Predictive Tool ◽  
Bending Process ◽  
Thin Walled Tube ◽  
Bending Radius ◽  
Thin Walled ◽  
Doubly Curved

Abstract Thin-walled tube bending has found many of its applications in the automobile and aerospace industries. This paper presents an energy approach to provide the minimum bending radius, which does not yield wrinkling in the bending process, as a function of tube and tooling geometry and material properties. A doubly-curved sheet model is established following the deformation theory. This approach provides a predictive tool in designing/optimizing the tooling parameters in the tube bending.

Theoretical, Numerical and Experimental Investigation of the Effects of Manufacturing Process Parameters on Thin-Walled Tube Bending Defects

2009 ◽  
Vol 83-86 ◽  
pp. 1107-1112
Author(s):  
J. Taheri Kahnamouei ◽  
Mohammad Sedighi
Keyword(s):  
Cross Section ◽  
Wall Thickness ◽  
Thickness Ratio ◽  
Outer Diameter ◽  
Tube Bending ◽  
Effective Parameters ◽  
Bending Process ◽  
Thin Walled Tube ◽  
Bending Radius ◽  
Thin Walled

The aim of this paper is to survey thin-walled tube bending process (without use of mandrel and booster). In tube bending process there are several effective parameters such as wall thickness, outer diameter-to-wall thickness ratio, and centerline bending radius-to-outer diameter ratio. Any mismatch in selecting these parameters would cause defects like wrinkling, variation in wall thickness, and cross section distortion. Firstly, the effects of these parameters on the initiation of the wrinkle, depth of wrinkling, change in wall thickness, and cross section distortion are studied. For this purpose, an FE commercial code has been used to simulate the process. Then, a series of experimental tests have been carried out to verify the results simulation. A comparison between analytical and experimental results shows a reasonable agreement with each other. Based on this comparison, it has been observed that there is a critical bending radius for any tube with a certain radius and thickness, in which the wrinkling begins to occur. For a certain bending angle and radius, it have been observed that the depth of wrinkling, change in wall thickness, and cross section distortion increase with reduction in wall thickness and outer diameter-to-wall thickness ratio

Wrinkling Limit Based on FEM Virtual Experiment during NC Bending Process of Thin-Walled Tube

2004 ◽  
Vol 471-472 ◽  
pp. 498-502 ◽  
Author(s):  
Heng Li ◽  
He Yang ◽  
Mei Zhan ◽  
L.G. Guo ◽  
R.J. Gu
Keyword(s):  
Forming Limit ◽  
Virtual Experiment ◽  
Prediction System ◽  
Tube Bending ◽  
Forming Parameters ◽  
Bending Process ◽  
Thin Walled Tube ◽  
Thin Walled ◽  
Definition Of ◽  
Nc Bending

A definition of forming limit is given with minimum centerline radius min R before wrinkling for NC bending process of thin-walled tube. Based on the developed FEM wrinkling prediction system TBWS-3D, an effective searching algorithm of wrinkling limit is proposed and forming limit can be obtained conveniently. Thus influence laws of main forming parameters on wrinkling limit are investigated and revealed. Measures to improve forming limit is put forward consequently. The achievements may help to both practice of thin-walled precise tube bending and research of plastic wrinkling.

Modeling and Experimental Validation of the Effect of Sand Filling on Avoiding Wrinkling Phenomenon in Thin-Walled Tube Bending Process

2010 ◽  
Author(s):  
Jalal Taheri Kahnamouei ◽  
Bashir Behjat
Keyword(s):  
Wall Thickness ◽  
Experimental Tests ◽  
Element Model ◽  
Thickness Ratio ◽  
Outer Diameter ◽  
Tube Bending ◽  
Effective Parameters ◽  
Bending Process ◽  
Bending Radius ◽  
Thin Walled

This paper investigates a method to avoid the wrinkling in thin-walled tubes in bending process. In the tube bending process there are several effective parameters such as wall thickness, outer diameter-to-wall thickness ratio, centerline bending radius-to-outer diameter ratio. Any mismatch in the selection of the process parameters would cause defects like wrinkling, serve changes in wall thickness, and cross section distortion. For example, the depth of wrinkling increases with reduction in wall thickness and outer diameter-to-wall thickness ratio for a certain bending angle and radius. In this research, to avoid wrinkle initiation, tube is filled by sand and then bended. This sandy core is supported the tube from inner, and tube is prepared to bending. After bending process, sand is removed. In this work, to study the process numerically, a 3D finite element model of the horizontal bending process is built using ANSYS software. Then, experimental tests have been carried out to verify the simulation results and are developed to provide additional insight. A comparison between numerical and experimental results shows a reasonable agreement. It shows that wrinkle initiation can be avoided with filler material like sand.

scholarly journals Optimal Design of the Shape of a Non-Ball Mandrel for Thin-Walled Tube Small Radius Cold Bending

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1221
Author(s):  
Lu Bai ◽  
Jun Liu ◽  
Ziang Wang ◽  
Shuanggui Zou
Keyword(s):  
Ideal Point ◽  
Small Radius ◽  
Grey Wolf Optimizer ◽  
Forming Quality ◽  
Hollow Section ◽  
Cold Bending ◽  
Bending Process ◽  
Before And After ◽  
Thin Walled Tube ◽  
Thin Walled

In the field of cold bending, it is necessary to use ball mandrels, especially to bend thin-walled tubes with a small radius. However, the bending process with a ball mandrel is complex and expensive, and it is easy to jam the core ball inside the tube. To solve these issues, we designed two kinds of hollow non-ball mandrel schemes with low stiffness that were suitable for the small radius bending of thin-walled tubes. We evaluated the forming quality of cold bending numerically and the influence of the hollow section length and thickness on the forming indices. Our results showed that the thickness of the hollow section has a greater influence on forming quality than the length. As the hollow section’s thickness increased, the wrinkling rate first declined by approximately 40% and then increased by above 50%. When the thickness was 11 mm in scheme 1 and 13 mm in scheme 2, the wrinkling rate reached minimum values of 1.32% and 1.50%, respectively. As the hollow section’s thickness increased, the flattening rate decreased by more than 60% and the thinning rate increased by about 40%. A multi-objective optimization of forming indices was carried out by ideal point method and grey wolf optimizer. By comparing the forming results before and after optimization, the feasibility of using the proposed hollow mandrel was proved, and the hollow mandrel scheme of standard cylinder is therefore recommended.

Investigation on the influence of mandrel on the forming quality of thin-walled tube during free bending process

2021 ◽  
Vol 72 ◽  
pp. 215-226
Author(s):  
Cheng Cheng ◽  
Hao Chen ◽  
Jiaxin Guo ◽  
Xunzhong Guo ◽  
Yuanji Shi
Keyword(s):  
Forming Quality ◽  
Bending Process ◽  
Thin Walled Tube ◽  
Thin Walled ◽  
Free Bending

Computational Modeling and Energy Absorption Behavior of Thin-Walled Tubes with the Kresling Origami Pattern

2021 ◽  
Vol 62 (2) ◽  
pp. 71-81
Author(s):  
Jiaqiang Li ◽  
Yao Chen ◽  
Xiaodong Feng ◽  
Jian Feng ◽  
Pooya Sareh
Keyword(s):  
Energy Absorption ◽  
Material Properties ◽  
Rotation Angle ◽  
Programming Model ◽  
Mixed Integer ◽  
Element Analysis ◽  
Cross Sectional ◽  
Thin Walled Tube ◽  
Absorption Performance ◽  
Thin Walled

Origami structures have been widely used in various engineering fields due to their desirable properties such as geometric transformability and high specific energy absorption. Based on the Kresling origami pattern, this study proposes a type of thin-walled origami tube the structural configuration of which is found by a mixed-integer linear programming model. Using finite element analysis, a reasonable configuration of a thin-walled tube with the Kresling pattern is firstly analyzed. Then, the influences of different material properties, the rotation angle of the upper and lower sections of the tube unit, and cross-sectional shapes on the energy absorption behavior of the thin-walled tubes under axial compression are evaluated. The results show that the symmetric thin-walled tube with the Kresling pattern is a reasonable choice for energy absorption purposes. Compared with thin-walled prismatic tubes, the thin-walled tube with the Kresling pattern substantially reduces the initial peak force and the average crushing force, without significantly reducing its energy absorption capacity; moreover, it enters the plastic energy dissipation stage ahead of time, giving it a superior energy absorption performance. Besides, the material properties, rotation angle, and cross-sectional shape have considerable influences on its energy absorption performance. The results provide a basis for the application of the Kresling origami pattern in the design of thin-walled energy-absorbingstructures.

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