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Bending Radius

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H. K. Yang – 1st expert on this subject based on the ideXlab platform

  • Significance-based optimization of processing parameters for thin-walled aluminum alloy tube NC Bending with small Bending Radius
    Transactions of Nonferrous Metals Society of China (English Edition), 2012
    Co-Authors: H. K. Yang, Heng Li, Mei Zhan

    Abstract:

    Thin-walled aluminum alloy tube numerical control (NC) Bending with small Bending Radius is a complex process with multi-factor coupling effects and multi-die constraints. A significance-based optimization method of the parameters was proposed based on the finite element (FE) simulation, and the significance analysis of the processing parameters on the forming quality in terms of the maximum wall thinning ratio and the maximum cross section distortion degree was implemented using the fractional factorial design. The optimum value of the significant parameter, the clearance between the tube and the wiper die, was obtained, and the values of the other parameters, including the friction coefficients and the clearances between the tube and the dies, the mandrel extension length and the boost velocity were estimated. The results are applied to aluminum alloy tube NC Bending d 50 mm×1 mm ×75 mm and d 70 mm×1.5 mm×105 mm (initial tube outside diameter D 0×initial tube wall thickness t 0×Bending Radius R), and qualified tubes are produced. © 2012 The Nonferrous Metals Society of China.

  • Analysis of wrinkling limit of rotary-draw Bending process for thin-walled rectangular tube
    Journal of Materials Processing Technology, 2010
    Co-Authors: G. Y. Zhao, H. K. Yang, Y.l. Liu, C. S. Dong, X. G. Fan

    Abstract:

    The rotary-draw Bending process for thin-walled rectangular tube of aluminum alloy may produce a wrinkling phenomenon if processing parameters are inappropriate, especially for tubes with thin wall and small Bending Radius. To predict this wrinkling rule rapidly and accurately, here, a wrinkling wave function was proposed and a wrinkling prediction model was developed based on the deformation theory of plasticity combined with the energy method, and then the minimum Bending Radius without the occurrence of wrinkling in the process was obtained. Furthermore, the effects of geometrical parameters and the material properties of the tube on the minimum Bending Radius were analyzed. The results show that larger thickness-to-width ratio (t/b) and thickness-to-height ratio (t/h) are beneficial to improve the wrinkling limit of the tube. The minimum Bending Radius becomes smaller with an increase in strain-hardening exponent of the tube, whereas with the strength coefficient decreasing. And the Young’s modulus has little effect on the wrinkling limit. These achievements are helpful to develop the Bending technique and provide a guideline in rotary-draw Bending process for thin-walled rectangular aluminum alloy tube. ?? 2010 Elsevier B.V. All rights reserved.

  • Numerical study on deformation behaviors of thin-walled tube NC Bending with large diameter and small Bending Radius
    Computational Materials Science, 2009
    Co-Authors: Heng Li, H. K. Yang, J Yan, Mei Zhan

    Abstract:

    With respect to wrinkling, wall thinning and cross section deformation, combined with analytical description, the deformation behaviors of thin-walled tube NC Bending with large diameter D/t (50.0-87.0) and small Bending Radius Rd/D (1.0-2.0) are explored via a series of reliable 3D-FE models under ABAQUS platform. The results show that: (1) The segmentation feature is observed for the deformation fields such as effective compressive/tensile regions τc / τt, stress/strain distributions, wrinkling tendency, wall thinning and cross section deformation. With smaller Rd/D, the tangent stress increases and becomes more inhomogenous. The maximum tangent stress σφ at the intrados increases by 46% with Rd/D from 2.0 to 1.2. While the distributions of σφ are nearly similar with larger D/t. With smaller Rd/D and larger D/t, the velocity variation of tube materials becomes more obvious. (2) The wrinkling tendency and cross section deformation degree Δ D increase with smaller Rd/D and larger D/t; With smaller Rd/D, both the wall thinning and thickening degrees increase. The maximum wall thinning and thickening degrees increase by 24.0% and 52.5%, respectively. However, with larger D/t, the wall thinning degree increases, while the thickening degree decreases significantly. The maximum wall thinning degree increases by 31.3%, while the maximum thickening one decreases by 58.9%. Crown Copyright © 2009.

Mei Zhan – 2nd expert on this subject based on the ideXlab platform

  • Significance-based optimization of processing parameters for thin-walled aluminum alloy tube NC Bending with small Bending Radius
    Transactions of Nonferrous Metals Society of China (English Edition), 2012
    Co-Authors: H. K. Yang, Heng Li, Mei Zhan

    Abstract:

    Thin-walled aluminum alloy tube numerical control (NC) Bending with small Bending Radius is a complex process with multi-factor coupling effects and multi-die constraints. A significance-based optimization method of the parameters was proposed based on the finite element (FE) simulation, and the significance analysis of the processing parameters on the forming quality in terms of the maximum wall thinning ratio and the maximum cross section distortion degree was implemented using the fractional factorial design. The optimum value of the significant parameter, the clearance between the tube and the wiper die, was obtained, and the values of the other parameters, including the friction coefficients and the clearances between the tube and the dies, the mandrel extension length and the boost velocity were estimated. The results are applied to aluminum alloy tube NC Bending d 50 mm×1 mm ×75 mm and d 70 mm×1.5 mm×105 mm (initial tube outside diameter D 0×initial tube wall thickness t 0×Bending Radius R), and qualified tubes are produced. © 2012 The Nonferrous Metals Society of China.

  • significance based optimization of processing parameters for thin walled aluminum alloy tube nc Bending with small Bending Radius
    Transactions of Nonferrous Metals Society of China, 2012
    Co-Authors: He Yang, Li Heng, Mei Zhan

    Abstract:

    Abstract Thin-walled aluminum alloy tube numerical control (NC) Bending with small Bending Radius is a complex process with multi-factor coupling effects and multi-die constraints. A significance-based optimization method of the parameters was proposed based on the finite element (FE) simulation, and the significance analysis of the processing parameters on the forming quality in terms of the maximum wall thinning ratio and the maximum cross section distortion degree was implemented using the fractional factorial design. The optimum value of the significant parameter, the clearance between the tube and the wiper die, was obtained, and the values of the other parameters, including the friction coefficients and the clearances between the tube and the dies, the mandrel extension length and the boost velocity were estimated. The results are applied to aluminum alloy tube NC Bending d 50 mm×1 mm ×75 mm and d 70 mm×1.5 mm×105 mm (initial tube outside diameter D 0 ×initial tube wall thickness t 0 ×Bending Radius R ), and qualified tubes are produced.

  • Numerical study on deformation behaviors of thin-walled tube NC Bending with large diameter and small Bending Radius
    Computational Materials Science, 2009
    Co-Authors: Heng Li, H. K. Yang, J Yan, Mei Zhan

    Abstract:

    With respect to wrinkling, wall thinning and cross section deformation, combined with analytical description, the deformation behaviors of thin-walled tube NC Bending with large diameter D/t (50.0-87.0) and small Bending Radius Rd/D (1.0-2.0) are explored via a series of reliable 3D-FE models under ABAQUS platform. The results show that: (1) The segmentation feature is observed for the deformation fields such as effective compressive/tensile regions τc / τt, stress/strain distributions, wrinkling tendency, wall thinning and cross section deformation. With smaller Rd/D, the tangent stress increases and becomes more inhomogenous. The maximum tangent stress σφ at the intrados increases by 46% with Rd/D from 2.0 to 1.2. While the distributions of σφ are nearly similar with larger D/t. With smaller Rd/D and larger D/t, the velocity variation of tube materials becomes more obvious. (2) The wrinkling tendency and cross section deformation degree Δ D increase with smaller Rd/D and larger D/t; With smaller Rd/D, both the wall thinning and thickening degrees increase. The maximum wall thinning and thickening degrees increase by 24.0% and 52.5%, respectively. However, with larger D/t, the wall thinning degree increases, while the thickening degree decreases significantly. The maximum wall thinning degree increases by 31.3%, while the maximum thickening one decreases by 58.9%. Crown Copyright © 2009.

Heng Li – 3rd expert on this subject based on the ideXlab platform

  • bp artificial neural network modeling for accurate Radius prediction and application in incremental in plane Bending
    The International Journal of Advanced Manufacturing Technology, 2015
    Co-Authors: He Yang, Heng Li, Honglie Zhang, Wenting Tang

    Abstract:

    Incremental in-plane Bending (IIB) is a new and advanced flexible manufacturing technology for small-lot production of strip with various Bending radii. The strip of sheet metal is bent incrementally by a beating inclined punch. The Bending Radius is strongly affected by mechanical properties of the material, geometry of the strip, and processing parameters. It is difficult to predict the Bending Radius due to the complex synergistic effects of the controlling parameters. How to predict the Bending Radius accurately has therefore become a key point to be urgently solved in the development of this advanced forming technology. In this paper, a model based on a back propagation neural network (BPNN) is introduced to reveal the relationship of Bending Radius with angle of die α, indentation s, pitch p, and width of strip w. Out of 14 different BPNN architectures trained, the 4-9-9-1 BPNN with two hidden layers having nine neurons trained with the Levenberg-Marquardt algorithm (trainlm) is found to be the optimum network model, and the prediction error is less than 2 % on average. Otherwise, a 1-9-9-4 reverse BPNN is developed to build the processing window for a given Bending Radius. Meanwhile, taking section moment of inertia I as a quantitative index of forming stability, α, p, s, w0 are optimized as design variables in order to make objective functions of I maximized simultaneously. Finally, to verify its predictive capability, the present approach is applied to a case study, and the optimal combination of parameters for stable forming during IIB is obtained.

  • FE-Based Analysis of Heat Bending of Thin-Walled Ti-Alloy Tube with Large Diameter and Small Bending Radius
    Advanced Materials Research, 2012
    Co-Authors: Heng Li, He Yang, Dan Wang, Zhiyong Zhang

    Abstract:

    The numerical control (NC) heat Bending of thin-walled Ti-alloy tube with large diameter and small Bending Radius with Ф50×1×R75mm (diameter OD Bending Radius CLR) is explored by 3D-FE thermal-mechanical coupling simulation of heat conducting and NC Bending. The results show that: (1) The heating of both pressure die and mandrel is proved to be appropriate to obtain the required temperature field. (2) In terms of wall thickness variation, wrinkling and cross-section deformation, the optimum span of the key parameters are obtained: the Bending velocity of 0.4rad/s, the matched pressure die speed of 80%-110%, and temperature of 600-800°C.

  • Significance-based optimization of processing parameters for thin-walled aluminum alloy tube NC Bending with small Bending Radius
    Transactions of Nonferrous Metals Society of China (English Edition), 2012
    Co-Authors: H. K. Yang, Heng Li, Mei Zhan

    Abstract:

    Thin-walled aluminum alloy tube numerical control (NC) Bending with small Bending Radius is a complex process with multi-factor coupling effects and multi-die constraints. A significance-based optimization method of the parameters was proposed based on the finite element (FE) simulation, and the significance analysis of the processing parameters on the forming quality in terms of the maximum wall thinning ratio and the maximum cross section distortion degree was implemented using the fractional factorial design. The optimum value of the significant parameter, the clearance between the tube and the wiper die, was obtained, and the values of the other parameters, including the friction coefficients and the clearances between the tube and the dies, the mandrel extension length and the boost velocity were estimated. The results are applied to aluminum alloy tube NC Bending d 50 mm×1 mm ×75 mm and d 70 mm×1.5 mm×105 mm (initial tube outside diameter D 0×initial tube wall thickness t 0×Bending Radius R), and qualified tubes are produced. © 2012 The Nonferrous Metals Society of China.