Effect of frictions on cross section quality of thin-walled tube NC bending

2006 ◽  
Vol 16 (4) ◽  
pp. 878-886 ◽  
Author(s):  
He YANG ◽  
Rui-jie GU ◽  
Mei ZHAN ◽  
Heng LI
Keyword(s):  
Cross Section ◽  
Thin Walled Tube ◽  
Thin Walled ◽  
Nc Bending

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

A Multi-Objective Optimization Method for Thin-Walled Tube NC Bending

2011 ◽  
Vol 213 ◽  
pp. 383-387
Author(s):  
Jie Xu ◽  
He Yang ◽  
Heng Li
Keyword(s):  
Uniform Design ◽  
Optimization Method ◽  
Maximum Height ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Thin Walled Tube ◽  
Design Values ◽  
Thin Walled ◽  
Aluminum Alloy Tube ◽  
Nc Bending

A multi-objective optimization method for thin-walled tube NC bending is presented. Firstly, a half-symmetry 3D elastic-plastic FEM model is established based on the initial design values, applying the dynamic explicit code ABAQUS/Explicit. Secondly, virtual orthogonal arrays are designed to optimize friction coefficients, with minimizing the maximum wall-thinning ratio, the maximum cross section distortion ratio and the maximum height of wrinkling waves as the multi-objectives. Lastly, the mandrel radius is optimized by sequential quadratic programming with approximate regressive models fit from uniform design values in the allowed range. Application is put forward for Ф50×1×100 (tube outside diameter ×tube wall thickness × central line bending radius) and Ф100×1.5×200 aluminum alloy tube bending. It is proved that the forming quality has been improved by the method.

Torsional Creep Buckling of Thin-Walled Open Tubes With a Cross Section Having an Axis of Symmetry

1962 ◽  
Vol 29 (1) ◽  
pp. 99-107
Author(s):  
George Lianis
Keyword(s):  
Cross Section ◽  
Closed Form Solution ◽  
Critical Time ◽  
Small Deformation ◽  
Form Solution ◽  
Creep Buckling ◽  
Thin Walled Tube ◽  
Axis Of Symmetry ◽  
Thin Walled ◽  
Stress Patterns

The variational theorem by Sanders, McComb, and Schlechte [1] is applied to find the critical collapse time of an open thin-walled tube with a cross section having an axis of symmetry subjected to torsional creep buckling. Large deformation strains are considered. It is shown that small deformation strains yield inaccurate results in predicting the critical time. A simplified stress distribution is introduced which gives a closed-form solution. More accurate stress patterns present considerable difficulties and a tedious numerical integration is needed. In examining most cases, however, the simplified stress configuration predicts the critical time very accurately.

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.

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.

scholarly journals Improvement of prt-9 constructive system on the basis of frame elements strength balance

2020 ◽  
Vol 100 (4) ◽  
pp. 40-45
Author(s):  
Taras Dovbush ◽  
Nadia Khomyk ◽  
Hanna Tson ◽  
Anatoliy Dovbush
Keyword(s):  
Cross Section ◽  
Rectangular Cross Section ◽  
Organic Fertilizer ◽  
Experimental Investigations ◽  
Thin Walled Tube ◽  
Thin Walled ◽  
Strength Uniformity ◽  
Shaped Cross Section ◽  
Main Frame

Analytical and experimental investigations of the most loaded elements of the base frame of PRT-9 solid organic fertilizer spreader are carried out in this paper. The residual operation life of the central beam of the paired Z-shaped profile, as well as the lateral spars of the Z-shaped cross section are determined. According to the results of studies, it was found that the residual operation life of these system elements differ significantly. In order to achieve strength uniformity of the main frame elements, it is decided to weaken the central beam by replacing the paired Z-shaped profile with a thin-walled tube of rectangular cross-section and strengthen the lateral spars by replacing Z-shaped profile with a channel profile with the same height.

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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