Investigation on the Process Parameters and Process Window of Three-Roll-Push-Bending

Plettke, Raoul; Vatter, Peter; Vipavc, Daniel; Cojutti, Massimo; Hagenah, Hinnerk

doi:10.1007/978-1-84996-432-6_5

Cited by 7 publications

(8 citation statements)

References 1 publication

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“…There are research efforts to determine the machine parameters needed to form the tube correctly and minimize deviation. These parameters would account for the material spring back and the deflection of the machine itself [48,49]. This method appears to have potential to be used for large scale fabrication of the CTGH.…”

Section: Tube Fabricationmentioning

confidence: 99%

Coiled Tube Gas Heaters For Nuclear Gas-Brayton Power Conversion

Peterson

2018

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Additionally, THERMOFLEX has the capability of estimating sizes of shell-and-tube heat exchangers, which although are not anticipated for use in our reference design, give an upper bound on component sizes, and are presented in Table 2. The high temperature recuperator requires approximately 14,000 m 2 of surface area given an overall heat transfer coefficient of 500 W/°C•m², which translates to a size of 4.9 by 23.6 m. As mentioned earlier this is about twice or more the size of the other heat exchangers, and also points to the need for a more compact design due to the low overall heat transfer coefficient. Spiral wound heat exchangers have overall heat transfer coefficients in the range of 700-2500 W/°C•m² [3], implying that the calculated volumes (lengths) in Table 2 can be reduced by a factor of 2 to 5. Component HT Recoup LT Recoup Water Cooler U 500.1 525.6 889.7 W/°C•m² A 13,859 6,387 4,299 m² D 4.864 4.22 3.183 m L 23.6 18.28 13.56 m V 438.5 255.7 107.9 m³ A/V 31.6 25.0 39.8 m²/m³ The development of a "high temperature" (700°C) CTGH design was deemed to be impractical due to the low allowable stresses of current code qualified materials at the anticipated operating point conditions. As such, a CTGH design and component sizing for the "medium-high temperature" (550°C) operating conditions appropriate for application to SFR's is being pursued. An "unconstrained" CAD model of the integral power conversion unit (PCU) was created, allowing for design flexibility based on estimated sizes of components. The major constraints imposed are simply the outer diameter of the vessel to maintain rail transportability. Figure 3 depicts the initial PCU design, including the turbomachinery, generator, external ducting with flow paths, recuperators and cooler. More detail will be added, including appropriate sizes for the heat exchangers, flow paths, insulation, etc. during the coming quarter.

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Section: Tube Fabricationmentioning

confidence: 99%

Coiled Tube Gas Heaters For Nuclear Gas-Brayton Power Conversion

Peterson

2018

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“…When referring to the cubic B-spline curve used in this work, it is the particular case that k = 3. To calculate the curvature and torsion at the points on the Bspline curves, the derivatives of the B-spline curves must be calculated according to equation (2). It can be seen that the derivatives of B-spline curve depend on the derivatives of B-spline basis functions.…”

Section: The Applications Of B-spline Curves On 3d Tubesmentioning

confidence: 99%

“…Three-dimensional (3D) bent tubes are nowadays finding widespread application in automotive industry, civil engineering as well as aviation and aerospace fields because of their advantageous characteristics such as space saving and optimal material distribution. At the same time, some new adaptive manufacturing techniques like free-bending, 1 three-roll-push-bending [2][3][4][5] and torque superposed spatial bending [6][7][8][9] are emerging constantly, which are especially suited for parts with complex 3D contours. The new techniques are labeled as flexible since they are usually the kinematic adjustment of the bending contour, which make it possible to produce tubes in any desired shape.…”

Section: Introductionmentioning

confidence: 99%

Springback predictions for three-dimensional thick-walled tubes based on the cylindrical helix splines

et al. 2017

The Journal of Strain Analysis for Engineering Design

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This article analyzed the forming process of thick-walled three-dimensional tubes under combined bending and twisting loads and performed the springback predictions based on the cylindrical helix splines. The equations to calculate the two kinds of moments consider the hardening effect, and they can be well applied to most materials. The cylindrical helix spline is adopted creatively to approximate the objective tube axis, and the curvature and the torsion of each cylindrical helix segment can represent the bending angle and the twisting angle per unit length of the corresponding tube element, respectively. All the cylindrical helix segments after springback are obtained based on the calculated moments and the final shape of the tube axis is achieved by connecting all of them through an appropriate splicing technology. Then, the whole deviations of the calculated shapes can be obtained. The method proposed is applied on a typical threedimensional tube forming and it has got good effect.

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“…And a finite element (FE) model which considers all of the relevant influences, such as the machine kinematics, the friction, and the machine stiffness, has been developed. [9][10][11][12] Springback occurs during the three-roll-push-bending process, but has not been quantified or modeled so far. A kinematic bending method known as torque superposed spatial (TSS) bending, which is flexible, continuous, and adaptive two-dimensional (2D) and 3D bending of profiles with symmetrical and asymmetrical cross sections, has been developed in IUL-TU, Dortmund.…”

Section: Introductionmentioning

confidence: 99%

Springback prediction of three-dimensional variable curvature tube bending

Zhang

2016

Advances in Mechanical Engineering

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The springback phenomenon of tube bending occurs consequentially after unloading, which will affect the manufacturing accuracy and processing efficiency of the tubular products. In this article, the bending and springback processes of minor-diameter thick-walled tube are simulated by ABAQUS to reveal the springback laws. The springback prediction of three-dimensional variable curvature bent tube is projected on each discrete osculating and rectifying plane, and then the three-dimensional problem can be transformed into two dimensions. The mathematic relationship of the radius before and after springback in the plane is built by approximate pure bending springback experiments. The springback on such planes is transformed into three dimensions. The tube axes are merged by first-order geometric (G1) continuity and then compensated with the modified function according to the axis complexity, so as to establish mathematic analytic model for springback prediction of three-dimensional variable curvature tube bending. Finally, the feasibility, reliability, and accuracy of the model are verified by finite element method and experiments.

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Investigation on the Process Parameters and Process Window of Three-Roll-Push-Bending

Cited by 7 publications

References 1 publication

Coiled Tube Gas Heaters For Nuclear Gas-Brayton Power Conversion

Coiled Tube Gas Heaters For Nuclear Gas-Brayton Power Conversion

Springback predictions for three-dimensional thick-walled tubes based on the cylindrical helix splines

Springback prediction of three-dimensional variable curvature tube bending

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