Push-bending method development of thin-walled tube with relative bending radius of 1 using sectional elastomers as mandrel

2019 ◽  
Vol 105 (1-4) ◽  
pp. 995-1008 ◽  
Author(s):  
Xuefeng Xu ◽  
Kongwei Wu ◽  
Yiwang Wu ◽  
Chunlin Fu ◽  
Yubin Fan
Keyword(s):  
Method Development ◽  
Thin Walled Tube ◽  
Bending Radius ◽  
Thin Walled

A STUDY ON STEPWISE OPTIMIZATION OF FORMING PARAMETERS FOR THIN-WALLED TUBE NC BENDING

2008 ◽  
Vol 07 (01) ◽  
pp. 15-20 ◽  
Author(s):  
JIE XU ◽  
HE YANG ◽  
MEI ZHAN ◽  
HENG LI
Keyword(s):  
Optimization Design ◽  
Expert Knowledge ◽  
Complex Method ◽  
Fem Model ◽  
Forming Parameters ◽  
Thin Walled Tube ◽  
Bending Radius ◽  
Thin Walled ◽  
Extension Length ◽  
Nc Bending

The optimization design of forming parameters for thin-walled tube NC bending is a complicated problem with multi-objectives, multi-variables and multi-constraints. A stepwise optimizing strategy is proposed to solve the problem. Initial values are determined according to the databases and expert knowledge, and then the forming parameters are optimized by adopting diverse methods after reducing their range gradually. The optimization processes implementing the strategy are carried out for the bending of stainless steel and aluminum alloy tubes with thickness of 1 mm, outside diameter of 38 mm, and bending radius of 57 mm. The FEM model established by ABAQUS/Explicit is used. Free wrinkling, the allowed cross-section distortion degree and other engineering demands are constraint conditions, and the minimum wall thinning ratio is defined as the optimization objective. The optimal values of the number of mandrel balls and the clearance between mandrel balls are obtained step by step respectively. Then the mandrel extension length and the boosting velocity of the pressure die are optimized by the complex method. The experiments are performed to verify the optimization results.

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.

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 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.

A New Bionic Elastic Mandrel for Application in the Spatial Consecutive RDB with no Straight Line

2015 ◽  
Vol 25 ◽  
pp. 12-18 ◽  
Author(s):  
Lan Fang Jiang ◽  
Wei Ming Lin ◽  
Dong Hui Wen ◽  
Hong Liu ◽  
Cong Da Lu ◽  
...  
Keyword(s):  
Structural Characteristics ◽  
Internal Surface ◽  
Forming Process ◽  
Straight Line ◽  
Space Saving ◽  
Thin Walled Tube ◽  
Bending Radius ◽  
Continuous Support ◽  
Thin Walled ◽  
Draw Bending

Thin-walled spatial bending tube can not only provide engineering design with higher flexibility and lighter structure, but also enhance the construction of space saving and aerodynamics improvement. Based on rotary draw bending technique, a new method for spatial consecutive bending with no straight line for thin-walled tube was put forward. Firstly, a new bionic elastic mandrel was developed by analyzing the structural characteristics of the squilla. It mainly consisted of bowl-shaped mandrel balls, an elastomer and a mandrel shank. The bowl-shaped mandrel balls, nested matching one another, generated a non-smooth surface which can provide continuous support for internal surface of the tube wall. It could also achieve small bending radius. The elastomer featured of certain bending stiffness and enough tensile strength. Secondly, a curved clamping die was advanced to clamp the spatial consecutive bending tube with no straight line effectively. Based on the shape of the bending tube after the former bending forming process, the curved clamping dies which can match the shape of the former bending tube were designed for the later bending. Lastly, bending experiments was performed. A thin-walled tube made of Q235 with two passes, one bending angle 90° and the other 180° was taken for example and the spatial consecutive bending tube with no straight line was successfully obtained. It is of significant importance in enriching the spatial bending tube technique and achieving the small bending radius.

NICROBRAZ 50

Alloy Digest ◽  
1994 ◽  
Vol 43 (8) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Honeycomb Structures ◽  
Thin Walled Tube ◽  
Thin Walled ◽  
Low Solubility

Abstract NICROBRAZ 50 is a low-melting, free-flowing filter metal for honeycomb structures and thin-walled tube assemblies. It has low solubility. This datasheet provides information on composition, physical properties, and hardness. It also includes information on corrosion resistance as well as joining. Filing Code: Ni-460. Producer or source: Wall Colmonoy Corporation.

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.

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