A new method for feasibility study and determination of the loading curves in the rotary draw-bending process

Mentella, A.; Strano, Matteo; Gemignani, R.

doi:10.1007/s12289-008-0017-0

Cited by 14 publications

(5 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…4 The main purpose of using the wiper die is to provide additional support to the tube behind the tangent point of the bend and it helps to prevent wrinkling at the intrados of the tube. 2 The wiper die also minimizes frictional drag during the bending operation. 8 An internal mandrel should be used for the operations, which include larger diameter and thin-walled tubes to substantially prevent cross-section deformation and to reduce ovality.…”

Section: Finite Element Analysismentioning

confidence: 99%

“…where 2 is the process variance and R the N Â N correlation matrix; N is the number of sampling points. The term R(x i , x j ) is the correlation function between two sampling points x i and x j .…”

Section: Radial Basis Functionsmentioning

confidence: 99%

“…1 Thin-walled tubes can be easily bent in desired small radii using a rotary-draw tube bending machine; moreover, low operating costs and high tooling variety are the most obvious advantages of this bending method. 2 A typical CNC rotary-draw tube bending machine includes five main bending components, as shown in Figure 1. These are: (i) the bend die, (ii) the bend die assistant, (iii) the clamp die, (iv) the wiper die, and (v) the pressure die.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Investigation and prediction of springback in rotary-draw tube bending process using finite element method

Sözen

Güler

Bekar

et al. 2012

Proceedings of the Institution of Mechanical Engineers, Part C:

View full text Add to dashboard Cite

Rotary-draw tube bending operation is one of the most universal methods used for the tube forming processes. Similar to the other forming methods, some problems such as wall thinning, cross-section distortion, wrinkling, and springback can also be seen on the tubes formed by rotary-draw bending operations. Springback is a very common problem and its prediction plays a crucial role in increasing the efficiency of the tube bending operations and also to overcome the difficulties in the assembly processes. Tube diameter, wall thickness, bend radius, bend angle, and coefficient of friction can be considered as the most effective parameters that cause the variation of springback magnitude. In this study, not a simple one-at-a-time sensitivity analysis, but a thorough investigation of the springback phenomena involving interactions between the geometrical and mechanical parameters is done and surrogate models are developed via the data obtained from finite element analysis using a multi-purpose explicit and implicit finite element software LS-DYNA to analyze the non-linear response of structures. The constructed surrogate models can be utilized to perform fast prediction of springback for a given combination of parameters. Three different surrogate modeling techniques are exploited and it is found that the linear polynomial response surface approximations can provide acceptable accuracy. Finally, experiments are conducted to validate the accuracy of surrogate models. It is observed that the cross-validation error predictions are close to the errors observed in the experiments.

show abstract

Section: Finite Element Analysismentioning

confidence: 99%

Section: Radial Basis Functionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Investigation and prediction of springback in rotary-draw tube bending process using finite element method

Sözen

Güler

Bekar

et al. 2012

Proceedings of the Institution of Mechanical Engineers, Part C:

View full text Add to dashboard Cite

show abstract

“…This method can reduce the cost of production due to decreasing wastes. Among other advantages of this method, quality, accuracy, high repeatability, automation, and mass production can be noteworthy [2]. Rotary draw tube bending provides close control of metal flow necessary for small radius and thin-walled tube [3].…”

Section: Introductionmentioning

confidence: 99%

Predicting the bending limit of AA8112 tubes using necking criterion in manufacturing of bent tubes

Elyasi

Mehrdad

Hosseinzadeh

2016

Int J Adv Manuf Technol

View full text Add to dashboard Cite

Nowadays, thin-walled tube bending at small bending ratios is a production process widely used in advanced industries. This research has been carried out to obtain the smallest bending ratio, and maximum applicable internal pressure in Hydro-rotary draw bending of thin-walled AA8112 alloy tube using necking criterion. To accomplish the objective, equivalent plastic strain of extrados critical region has been selected for necking criterion. The results showed that the selected necking criterion would be able to successfully determine the onset of rupture in bending. In order to validate FE simulation, the effects of bending ratio and internal pressure on defects, such as cross-section ovality and thickness changing, have also been investigated through simulation in ABAQUS software and experiments.

show abstract

“…If no lubricant is applied, it is difficult to remove the mandrel at the end of the process and the internal wall of the tube may result in being very rough due to friction between the mandrel and the tube. Another limitation in bending, involving long tubes with small diameters and relatively thin walls, concerns the action of the axial tube booster, which can produce undesired wrinkling [9]. The axial motion of the pressure die is also generally not employed, because in general purpose rotary draw bending machines, the tube dimensions are too small for standard actuators.…”

Section: Introductionmentioning

confidence: 99%

Rotary draw bending of small diameter copper tubes: predicting the quality of the cross-section

Mentella¹,

Strano

2011

Proceedings of the Institution of Mechanical Engineers, Part B:

View full text Add to dashboard Cite

The purpose of the present work is to study the correlation between the main geometrical tube parameters of the rotary draw bending process and the resulting quality of the cross-section of small hydraulic pipings. The method of choice, named free rotary draw bending, is a rotary draw bending process where no internal support from an internal mandrel or plug is\ud possible, because hydraulic tubes cannot be lubricated on their internal diameter. Furthermore, no axial boosting of the tube or of the pressure die is applied. Free bending is mainly used when\ud small-diameter tubes are involved, with high length and relatively thin wall. \ud A unique quality estimator QCS of the cross-section geometry of bent tubes has been developed, which is able to synthetically represent the main functional and aesthetical properties of tubes:\ud the maximum ovalization, the minimum hydraulic diameter, and so on. In the case of copper tubes for hydraulic applications a strongly deformed cross-section after bending means a poor\ud quality of the product, since it delivers an increase of head losses and of pressure drops. The deformation occurring in the cross-section of the tube has been studied through a set of FEM simulations, run with an explicit code with shell elements, and the model has been validated by comparing the experimental and numerical results of specific cases, in terms of geometry of\ud the cross-section in a 90 bend. The plan of simulations has been designed using the typical copper tube dimensions for hydro-thermo-sanitary applications and a few runs have been added with modified parameters with the aim of completing the plan for evaluating the sensitivity to a change either in geometrical variables (thickness t, outer diameter OD, mean bending radius RM) or in the tube material. An indicator (bending factor) is proposed, able to reliably estimate the difficulty of a bending process with respect to tendency to ovalization and collapse of the crosssection.\ud Some design guidelines of the bending tools are provided

show abstract

A new method for feasibility study and determination of the loading curves in the rotary draw-bending process

Cited by 14 publications

References 1 publication

Investigation and prediction of springback in rotary-draw tube bending process using finite element method

Investigation and prediction of springback in rotary-draw tube bending process using finite element method

Predicting the bending limit of AA8112 tubes using necking criterion in manufacturing of bent tubes

Rotary draw bending of small diameter copper tubes: predicting the quality of the cross-section

Contact Info

Product

Resources

About