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

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.

Springback Analysis of Thin-Walled Stainless Steel Bellow in Hydroforming

2015 ◽  
Vol 1095 ◽  
pp. 855-858 ◽  
Author(s):  
Jing Liu ◽  
Yang Liu ◽  
Lan Yun Li ◽  
Xiao Li ◽  
Shao Fei Yang ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Stress Distribution ◽  
Radial Displacement ◽  
Axial Displacement ◽  
Fe Model ◽  
Forming Quality ◽  
Compressive Stresses ◽  
Thin Walled ◽  
Profile Change

Springback has an important influence on the forming quality of thin-walled stainless bellows hydroforming. By developing a FE model, the stress distribution is investigated and springback characteristics of two specification bellows are addressed. The results show that: (1) For tube Φ26×0.5, the maximum circumferential tensile/compressive stresses decrease by 32% and 29.1% after springback, respectively. The maximum longitudinal tensile/compressive stresses decrease by 51.8% and 39.6%, respectively. (2) Three indices are proposed to describe the bellow profile change after springback, namely, radial displacement of crown point; axial displacement of inner point; maximum convolution width. (3) For tube Φ26×0.1, after springback, the inward shrinkage of crown point increases by 0.7%, the bellow axial elongation is 0.76mm, the maximum convolution width increases by 30.3%.

Study and Build-Up of Deformation Zone at Cutting of Thin-Walled Tube by Torsion

2017 ◽  
Vol 746 ◽  
pp. 16-21
Author(s):  
S.G. Simagina
Keyword(s):  
Deformation Zone ◽  
Heating Temperature ◽  
Compression Force ◽  
Angular Deflection ◽  
Thin Walled Tube ◽  
Temperature Impact ◽  
Thin Walled ◽  
Force Range ◽  
Intensive Development

Intensive development of Russian aviation and aerospace industries put an emphasis to the problem of quality of using materials and workpieces and to the value of technical and economical indexes in the context of planned production level [1, 2]. Waste-free technologies are preferred. Cutting by torsion or cutting by shear are preferable technologies if thin-walled tube cutting is the main blanking operation. Build-up of workpiece deformation zone plays an important role in the cutting process. Deformation zone determines stability of details during further processing and exploitation. An extended research was conducted about tube separation process using torsion with an active counterpressure. Some parameters was defined in the result of research, in particular: distribution of deformation zone along length and thickness of workpiece, angular deflection and compression force and workpiece heating temperature impact on build-up of whisker disposition in the cut zone. It allows identifying optimum compression force range and temperature conditions. Compliance with recommended practices allows conducting thin-walled tube separation simultaneously with build-up on the workpieces whisker structure that is fortunate for further pressure treatment and exploitation.

scholarly journals Twist Springback of Asymmetric Thin-walled Tube in Mandrel Rotary Draw Bending Process

2014 ◽  
Vol 81 ◽  
pp. 2177-2183 ◽  
Author(s):  
Xin Xue ◽  
Juan Liao ◽  
Gabriela Vincze ◽  
Jose Gracio
Keyword(s):  
Rotary Draw Bending ◽  
Bending Process ◽  
Thin Walled Tube ◽  
Thin Walled ◽  
Twist Springback ◽  
Draw Bending

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.

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