The Experts below are selected from a list of 2997 Experts worldwide ranked by ideXlab platform
Dosik Shim - One of the best experts on this subject based on the ideXlab platform.
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Improvement strategy for edge waviness in Roll Bending process of corrugated sheet metals
International Journal of Material Forming, 2017Co-Authors: Dosik Shim, Gyeong-yun BaekAbstract:This paper focuses on the corrugated thin-walled sheet metal in the Roll Bending process. The main defect that appears in corrugated panels subjected to high amounts of Bending deformation is a wavy edge. Edge defects are caused by excessive longitudinal stress and strain near the edge of the plate, and local edge buckling may occur when some critical value of the Bending radius is exceeded. This paper proposes two different approaches to avoid a wavy edge for a formed panel: excessive stress on the edge region is restrained by contRolling the length of the cross-sectional end of the corrugated panel while considering the stress distribution, and the Bending radius in each forming step is determined by considering the strain limit at which the initial edge waviness occurs to avoid excessive compression at particular steps. The experimental and numerical results indicated that the two proposed design strategies can minimize wavy edges in the formed shape.
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double stage forming using critical pre Bending radius in Roll Bending of pipe with rectangular cross section
Journal of Materials Processing Technology, 2016Co-Authors: Dosik ShimAbstract:Abstract Bent pipes are widely used in many high-end industries as a structural component. Consequently, pipe Roll Bending has become an attractive manufacturing technology for forming lightweight products. For industrial applications, bent pipes should be accurately shaped into 2D or 3D shapes without defects. In this study, the behavior of pipes with rectangular cross-sections under Roll Bending was considered in order to improve product quality. When a pipe product is bent with a large curvature, the pipe cross-section shrinks under the Bending moment. In order to minimize defects and improve product quality, this paper proposes double-stage forming to regulate the shrinking load, which causes the axial wrinkles and poor strength, as structural members. In double-stage forming, the Bending radius at the pre-Bending stage is assumed to be a key parameter to avoid cross-section distortion. In order to determine the pre-Bending radius, material behavior was analyzed to figure out the reason for the cross-section shrinkage. The Bending stresses on the cross-section of the pipe material subject to Bending moments bring about the distribution of inward forces, which induce shrinkage moments on the cross-section. The main idea in this paper is that the cross-section distortion can be minimized by regulating the pre-Bending radius at the first stage. The proposed process design was evaluated through nonlinear finite element simulation using a commercial program and experiments.
Henri Champliaud - One of the best experts on this subject based on the ideXlab platform.
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Experimental analysis of an asymmetrical three-Roll Bending process
The International Journal of Advanced Manufacturing Technology, 2016Co-Authors: Jamel Salem, Henri Champliaud, Zhengkun Feng, Thien-my DaoAbstract:The asymmetrical three-Roll Bending process is commonly used to manufacture cylindrical and conical sections from flat plates. The Roll Bending forces, the residual stresses, and the required Roll Bending power are influenced by material properties and process parameters, such as yield stress, plate thickness, curvature, and conicity for a truncated cone. In the present paper, an analytical model is developed to predict Roll Bending force, residual stresses, and power of Roll Bending process. To verify the developed model, asymmetrical three-Roll Bending experiments are performed. The results given by analytical model are in agreement with the experimental results. The analytical model has shown that an increase of the yield stress of material, or plate thickness or conicity requires more Roll Bending forces, Roll Bending power during Roll Bending process and results in residual stresses in the final shape. On other hand, an increase of the radius of bent shape requires less Roll Bending forces, less Roll Bending power, and results in less residual stresses in the final shape. Geometric verification of bent shapes has shown that when the yield stress, the thickness, or the conicity of the bent shape increases, the bent shape has less geometric defects. On the contrary, it was found that when the radius of curvature increases, the final shape has more geometric defects.
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Analysis of the asymmetrical Roll Bending process through dynamic FE simulations and experimental study
The International Journal of Advanced Manufacturing Technology, 2014Co-Authors: Quan Hoang Tran, Henri Champliaud, Zhengkun Feng, Thien-my DaoAbstract:Because it is influenced by various processing parameters, predicting the Bending force and improving the accuracy of the final shape are significant challenges in the Roll Bending process when the part to be produced is large and made of high-strength steel. In this paper, a 3D dynamic finite element (FE) model of an asymmetrical Roll Bending process is developed using the ANSYS/LS-DYNA software. This model investigates the parameters that affect the accuracy of the final shape, the Bending forces, and the residual strains left in the formed plate. The simulation results are then compared with experiments performed on an instrumented Roll Bending machine. Strain measurements are also performed during forming with strain gauges fixed onto plate blanks. A good agreement between the experiments and simulations has been obtained.
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Using Pyramidal Three-Roll Bending Process to Improve the Quality of Seamed Cylinders
Volume 2A: Advanced Manufacturing, 2013Co-Authors: Zhengkun Feng, Henri ChampliaudAbstract:Mecano-welding can efficiently produce cylinders used in various industries. The pyramidal three-Roll Bending process is commonly used to produce a cylinder with non-seamed gap. However, there is a planar zone near the front and rear ends. This planar zone can be seamed with a welding process. In this paper, a numerical model is proposed to simulate the Roll Bending process and the welding process so that the geometrical quality of the bent cylinders can be improved. Explicit and implicit solvers are applied to the numerical modeling by using ANSYS/LS-DYNA software. The numerical model can provide a useful tool for design and optimization of the Mecano-welding process.Copyright © 2013 by ASME
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Dynamic FE analysis for reducing the flat areas of formed shapes obtained by Roll Bending process
Volume 2A: Advanced Manufacturing, 2013Co-Authors: Hoang Quan Tran, Henri Champliaud, Zhengkun Feng, Thien-my DaoAbstract:Roll Bending is a continuous forming process where plates, sheets, beams, pipes, and even Rolled shapes and extrusions are bent to a desired curvature using forming Rolls. Over the years, with the advantages such as reducing setting up time, the cost in tooling investment and equipment, the Roll Bending process was fundamental for manufacturing cylindrical shapes. However, the process always leaves a flat area along the leading and trailing edges of the workpiece. Therefore, accuracy could be a challenge when the part to be produced is large and made of high strength steel. There are several methods to minimize the flat area. Among them, for the asymmetrical configuration, moving slightly the bottom Roll along the Rolling direction may have the highest effect. On the other hand local adjustment of the bottom Roll location is also important for providing the pressure needed for gripping and carrying the workpiece through the Rolls. Then by optimizing the vertical displacement of the bottom Roll one can minimize the span of flat areas.The main objective of this research is to assess 3D dynamic Finite Element (FE) model with Ansys/LS-Dyna for the simulation and analysis of the deformation of the workpiece during the manufacturing of cylindrical parts. Various dynamic simulations based on 3D element are performed to provide better understanding of the whole deformation history and to establish the relationship between the location of the bottom Roll and the end shapes of the formed cylinders. The results from FE simulations are then compared with corresponding experimental results from an industrial Roll Bending machine in order to improve the quality of the final shape.Copyright © 2013 by ASME
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Investigation of non-kinematic conical Roll Bending process with conical Rolls
Simulation Modelling Practice and Theory, 2012Co-Authors: Zhengkun Feng, Henri ChampliaudAbstract:Abstract Although high quality cones can be produced with kinematic conical Roll Bending due to the non-slide condition between the conical Rolls and the plate, the process flexibility is limited because the conical Rolls cannot be reused to produce cones of different cone angles. In this paper, a non-kinematic three-Roll Bending process is proposed to reduce manufacture costs by reusing existing conical Rolls. In this process, an attachment is added to the top edge of the plate to obtain required circumferential velocity as the top/bottom radius ratio of the desired cone is smaller than the Rolls. The top sides of the conical Rolls slide on the plate to reduce the local velocity near the top edge and an appropriate velocity near the top edge of the plate can be obtained by adjusting the friction coefficients between the Rolls and the plate. This flexible process can provide performance similar to the kinematic conical Roll Bending process. The process modeling is based on the finite element method under ANSYS/LS-DYNA environment. A relation between the gap size of the bent cone and the friction at the plate/attachment contact interface has been investigated by using numerical simulations. The simulation results give a well bent cone compared with an ideal cone.
Wen Xue Zhang - One of the best experts on this subject based on the ideXlab platform.
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A Robust Model for Work Roll Bending Control Reaching Threshold in Flatness Control of Cold Rolling Mill
Advanced Materials Research, 2010Co-Authors: Peng Fei Wang, Dian-hua Zhang, Wen Xue ZhangAbstract:The work Roll Bending is one of the most effective flatness actuators in flatness control of cold Rolled strips, as a result of its characteristics such as high speed response, powerful effects on the elimination of flatness defects such as edge-waves, central waves and so on. The existing research on flatness control mainly focuses on the calculation of optimal adjustment of individual flatness actuator. However, the final output of a flatness actuator is required to be limited firstly for some special cases. If the incoming strip is coming with big symmetrical flatness defects, it happens that the position limit of work Roll Bending is prone to be reached or exceeded during the execution of the displacement, resulting in the residual symmetrical flatness defects without further elimination, as well as a limited flatness control process. In order to avoid this situation, substitution control by intermediate Roll Bending in case of work Roll Bending control over-limitation have been developed, which is based on actuator efficiencies and in accordance with the practical conditions. Applications show that the substitution control of intermediate Roll Bending for work Roll Bending over-limitation can play an important role in the residually symmetrical flatness control.
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Performance Analysis of Asymmetrical Roll Bending for Flatness Control of Cold Rolling Mill
Advanced Materials Research, 2010Co-Authors: Dian-hua Zhang, Peng Fei Wang, Wen Xue ZhangAbstract:When there appeared catastrophic asymmetrical flatness defects in Rolling processes, especially when the incoming strip is with a wedge shape, the tilting Roll can hardly eliminate these defects completely. Moreover, the overshooting of tilting Roll will lead to strip break. In order to improve the ability of cold Rolling mill for asymmetrical flatness defects control, performance of the work Roll asymmetrical Bending as well as the intermediate Roll asymmetrical Bending has been analyzed, based on the actuator efficiency factors of them. In addition, for the purpose of obtaining accurate efficiency factors matrixes of actuators, a self-learning determination model of actuator efficiency factors was established in accordance with the practical Rolling processes. In this paper, a 1250 single stand 6-H reversible UCM cold mill was taken as the object of this study, with efficiency factors of asymmetrical Roll Bending analyzed, which provides a theoretical basis for better flatness control. Analysis shows that the asymmetrical Roll Bending is significant for asymmetrical flatness control.
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Analysis of Contact Pressure between Rolls under Non-Symmetrical Roll Bending of UCM Cold Rolling Mill
Advanced Materials Research, 2010Co-Authors: Dian-hua Zhang, Peng Fei Wang, Wen Xue ZhangAbstract:. For UCM cold Rolling mill, the intermediate Roll shifting can enhance the ability of mill for better flatness control, but it will increase the non-uniform distribution of pressure between Rolls, as result of a reduced Roll life. In order to improve the contact state among Rolls in Rolling processes and to slow down the Roll wear, the distribution of pressure between Rolls under different forms of Roll Bending control has been calculated and analyzed by the influence function method in this paper. For the purpose of obtaining comprehensive information, not only the distributions of pressure between Rolls with traditional work Roll symmetrical Bending and intermediate Roll symmetrical Bending have been analyzed, but also the distributions of pressure between Rolls with non-symmetrical Roll Bending have been analyzed. All the analyses show that the work Roll non-symmetrical Bending as well as the intermediate Roll non-symmetrical Bending can play an important role in the slowing down of Roll wear.
Dian-hua Zhang - One of the best experts on this subject based on the ideXlab platform.
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Research and application of non-symmetrical Roll Bending control of cold Rolling mill
Chinese Journal of Mechanical Engineering, 2012Co-Authors: Peng Fei Wang, Dian-hua Zhang, Jiawei Liu, Jun-sheng WangAbstract:The existing research of the flatness control for strip cold Rolling mainly focuses on the calculation of the optimum adjustment of individual flatness actuator in accordance with the flatness deviation, which can be used for general flatness control. However, it does not work for some special Rolling processes, such as the elimination of ultra single side edge-waves and the prevention of strip break due to tilting Roll control overshooting. For the purpose of solving these problems, the influences of non-symmetrical work Roll Bending and intermediate Roll Bending on flatness control were analyzed by studying efficiencies of them. Moreover, impacts of two kinds of non-symmetrical Roll Bending control on the pressure distribution between Rolls were studied theoretically. A non-symmetrical work Roll Bending model was developed by theoretical analysis in accordance with practical conditions. The model was applied to the revamp of a 1250 6-H reversible universal crown mill (UCM) cold mill. Theoretical study and practical applications show that the coordination utilization of the non-symmetrical work Roll Bending control and tilting Roll control was effective in flatness control when there appeared bad strip single side edge waves, especially when the incoming strip was with a wedge shape. In addition, the risk of strip break due to tilting control overshooting could be reduced. Furthermore, the non-symmetrical Roll Bending control can reduce the extent of uneven distribution of pressure between Rolls caused by intermediate Roll shifting in flatness control and slow down Roll wear. The non-symmetrical Roll Bending control technology has important theoretical and practical significance to better flatness control.
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A Robust Model for Work Roll Bending Control Reaching Threshold in Flatness Control of Cold Rolling Mill
Advanced Materials Research, 2010Co-Authors: Peng Fei Wang, Dian-hua Zhang, Wen Xue ZhangAbstract:The work Roll Bending is one of the most effective flatness actuators in flatness control of cold Rolled strips, as a result of its characteristics such as high speed response, powerful effects on the elimination of flatness defects such as edge-waves, central waves and so on. The existing research on flatness control mainly focuses on the calculation of optimal adjustment of individual flatness actuator. However, the final output of a flatness actuator is required to be limited firstly for some special cases. If the incoming strip is coming with big symmetrical flatness defects, it happens that the position limit of work Roll Bending is prone to be reached or exceeded during the execution of the displacement, resulting in the residual symmetrical flatness defects without further elimination, as well as a limited flatness control process. In order to avoid this situation, substitution control by intermediate Roll Bending in case of work Roll Bending control over-limitation have been developed, which is based on actuator efficiencies and in accordance with the practical conditions. Applications show that the substitution control of intermediate Roll Bending for work Roll Bending over-limitation can play an important role in the residually symmetrical flatness control.
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Performance Analysis of Asymmetrical Roll Bending for Flatness Control of Cold Rolling Mill
Advanced Materials Research, 2010Co-Authors: Dian-hua Zhang, Peng Fei Wang, Wen Xue ZhangAbstract:When there appeared catastrophic asymmetrical flatness defects in Rolling processes, especially when the incoming strip is with a wedge shape, the tilting Roll can hardly eliminate these defects completely. Moreover, the overshooting of tilting Roll will lead to strip break. In order to improve the ability of cold Rolling mill for asymmetrical flatness defects control, performance of the work Roll asymmetrical Bending as well as the intermediate Roll asymmetrical Bending has been analyzed, based on the actuator efficiency factors of them. In addition, for the purpose of obtaining accurate efficiency factors matrixes of actuators, a self-learning determination model of actuator efficiency factors was established in accordance with the practical Rolling processes. In this paper, a 1250 single stand 6-H reversible UCM cold mill was taken as the object of this study, with efficiency factors of asymmetrical Roll Bending analyzed, which provides a theoretical basis for better flatness control. Analysis shows that the asymmetrical Roll Bending is significant for asymmetrical flatness control.
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Analysis of Contact Pressure between Rolls under Non-Symmetrical Roll Bending of UCM Cold Rolling Mill
Advanced Materials Research, 2010Co-Authors: Dian-hua Zhang, Peng Fei Wang, Wen Xue ZhangAbstract:. For UCM cold Rolling mill, the intermediate Roll shifting can enhance the ability of mill for better flatness control, but it will increase the non-uniform distribution of pressure between Rolls, as result of a reduced Roll life. In order to improve the contact state among Rolls in Rolling processes and to slow down the Roll wear, the distribution of pressure between Rolls under different forms of Roll Bending control has been calculated and analyzed by the influence function method in this paper. For the purpose of obtaining comprehensive information, not only the distributions of pressure between Rolls with traditional work Roll symmetrical Bending and intermediate Roll symmetrical Bending have been analyzed, but also the distributions of pressure between Rolls with non-symmetrical Roll Bending have been analyzed. All the analyses show that the work Roll non-symmetrical Bending as well as the intermediate Roll non-symmetrical Bending can play an important role in the slowing down of Roll wear.
Peng Fei Wang - One of the best experts on this subject based on the ideXlab platform.
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Research and application of non-symmetrical Roll Bending control of cold Rolling mill
Chinese Journal of Mechanical Engineering, 2012Co-Authors: Peng Fei Wang, Dian-hua Zhang, Jiawei Liu, Jun-sheng WangAbstract:The existing research of the flatness control for strip cold Rolling mainly focuses on the calculation of the optimum adjustment of individual flatness actuator in accordance with the flatness deviation, which can be used for general flatness control. However, it does not work for some special Rolling processes, such as the elimination of ultra single side edge-waves and the prevention of strip break due to tilting Roll control overshooting. For the purpose of solving these problems, the influences of non-symmetrical work Roll Bending and intermediate Roll Bending on flatness control were analyzed by studying efficiencies of them. Moreover, impacts of two kinds of non-symmetrical Roll Bending control on the pressure distribution between Rolls were studied theoretically. A non-symmetrical work Roll Bending model was developed by theoretical analysis in accordance with practical conditions. The model was applied to the revamp of a 1250 6-H reversible universal crown mill (UCM) cold mill. Theoretical study and practical applications show that the coordination utilization of the non-symmetrical work Roll Bending control and tilting Roll control was effective in flatness control when there appeared bad strip single side edge waves, especially when the incoming strip was with a wedge shape. In addition, the risk of strip break due to tilting control overshooting could be reduced. Furthermore, the non-symmetrical Roll Bending control can reduce the extent of uneven distribution of pressure between Rolls caused by intermediate Roll shifting in flatness control and slow down Roll wear. The non-symmetrical Roll Bending control technology has important theoretical and practical significance to better flatness control.
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A Robust Model for Work Roll Bending Control Reaching Threshold in Flatness Control of Cold Rolling Mill
Advanced Materials Research, 2010Co-Authors: Peng Fei Wang, Dian-hua Zhang, Wen Xue ZhangAbstract:The work Roll Bending is one of the most effective flatness actuators in flatness control of cold Rolled strips, as a result of its characteristics such as high speed response, powerful effects on the elimination of flatness defects such as edge-waves, central waves and so on. The existing research on flatness control mainly focuses on the calculation of optimal adjustment of individual flatness actuator. However, the final output of a flatness actuator is required to be limited firstly for some special cases. If the incoming strip is coming with big symmetrical flatness defects, it happens that the position limit of work Roll Bending is prone to be reached or exceeded during the execution of the displacement, resulting in the residual symmetrical flatness defects without further elimination, as well as a limited flatness control process. In order to avoid this situation, substitution control by intermediate Roll Bending in case of work Roll Bending control over-limitation have been developed, which is based on actuator efficiencies and in accordance with the practical conditions. Applications show that the substitution control of intermediate Roll Bending for work Roll Bending over-limitation can play an important role in the residually symmetrical flatness control.
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Performance Analysis of Asymmetrical Roll Bending for Flatness Control of Cold Rolling Mill
Advanced Materials Research, 2010Co-Authors: Dian-hua Zhang, Peng Fei Wang, Wen Xue ZhangAbstract:When there appeared catastrophic asymmetrical flatness defects in Rolling processes, especially when the incoming strip is with a wedge shape, the tilting Roll can hardly eliminate these defects completely. Moreover, the overshooting of tilting Roll will lead to strip break. In order to improve the ability of cold Rolling mill for asymmetrical flatness defects control, performance of the work Roll asymmetrical Bending as well as the intermediate Roll asymmetrical Bending has been analyzed, based on the actuator efficiency factors of them. In addition, for the purpose of obtaining accurate efficiency factors matrixes of actuators, a self-learning determination model of actuator efficiency factors was established in accordance with the practical Rolling processes. In this paper, a 1250 single stand 6-H reversible UCM cold mill was taken as the object of this study, with efficiency factors of asymmetrical Roll Bending analyzed, which provides a theoretical basis for better flatness control. Analysis shows that the asymmetrical Roll Bending is significant for asymmetrical flatness control.
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Analysis of Contact Pressure between Rolls under Non-Symmetrical Roll Bending of UCM Cold Rolling Mill
Advanced Materials Research, 2010Co-Authors: Dian-hua Zhang, Peng Fei Wang, Wen Xue ZhangAbstract:. For UCM cold Rolling mill, the intermediate Roll shifting can enhance the ability of mill for better flatness control, but it will increase the non-uniform distribution of pressure between Rolls, as result of a reduced Roll life. In order to improve the contact state among Rolls in Rolling processes and to slow down the Roll wear, the distribution of pressure between Rolls under different forms of Roll Bending control has been calculated and analyzed by the influence function method in this paper. For the purpose of obtaining comprehensive information, not only the distributions of pressure between Rolls with traditional work Roll symmetrical Bending and intermediate Roll symmetrical Bending have been analyzed, but also the distributions of pressure between Rolls with non-symmetrical Roll Bending have been analyzed. All the analyses show that the work Roll non-symmetrical Bending as well as the intermediate Roll non-symmetrical Bending can play an important role in the slowing down of Roll wear.
