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.

scholarly journals Cold Forging Effect on the Microstructure of Motorbike Shock Absorbers Fabricated by Tube Forming in a Closed Die

2021 ◽  
Vol 11 (5) ◽  
pp. 2142
Author(s):  
Trung-Kien Le ◽  
Tuan-Anh Bui
Keyword(s):  
Material Flow ◽  
Cold Forging ◽  
Technological Parameters ◽  
Forming Process ◽  
Tube Forming ◽  
Shock Absorbers ◽  
Thin Walled Tube ◽  
Thin Walled ◽  
Quality Of Products ◽  
Forming Defects

Motorbike shock absorbers made with a closed die employ a tube-forming process that is more sensitive than that of a solid billet, because the tube is usually too thin-walled to conserve material. During tube forming, defects such as folding and cracking occur due to unstable tube forming and abnormal material flow. It is therefore essential to understand the relationship between the appearance of defects and the number of forming steps to optimize technological parameters. Based on both finite element method (FEM) simulations and microstructural observations, we demonstrate the important role of the number and methodology of the forming steps on the material flow, defects, and metal fiber anisotropy of motorbike shock absorbers formed from a thin-walled tube. We find limits of the thickness and height ratios of the tube that must be held in order to avoid defects. Our study provides an important guide to workpiece and processing design that can improve the forming quality of products using tube forming.

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

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

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