Compare of shell element and solid element in roll forming simulation

2007 ◽  
Vol 340-341 ◽  
pp. 347-352 ◽  
Author(s):  
Da Yong Li ◽  
Ying Bing Luo ◽  
Ying Hong Peng

Solid shell element models which possess only translational degrees of freedom and are applicable to thin structure analyses has drawn much attention in recent years and presented good prospect in sheet metal forming. In this study, a solid shell element model is introduced into the dynamic explicit elastic-plastic finite element method. The plane stress constitutive relation is assumed to relieve the thickness locking and the selected reduced integration method is used to overcome volumetric locking. The assumed natural strain method is adopted to resolve shear locking and trapezoidal locking problem. Two benchmark examples and a stage of roll forming process are calculated, and the calculating results are compared with those by solid element model, which demonstrates the effectiveness of the element.


2011 ◽  
Vol 473 ◽  
pp. 564-571 ◽  
Author(s):  
Romain Boman ◽  
Jean Philippe Ponthot

Due to the length of the mill, accurate modelling of stationary solution of continuous cold roll forming by the finite element method using the classical Lagrangian formulation usually requires a very large mesh leading to huge CPU times. In order to model industrial forming lines including many tools in a reasonable time, the sheet has to be shortened or the element size has to be increased leading to inaccurate results. On top of this, applying loads and boundary conditions on this smaller sheet is usually more difficult than in the continuous case. Moreover, transient dynamic vibrations, which are unnecessarily computed, may appear when the sheet hits each tool, decreasing the convergence rate of the numerical simulation. Beside this classical Lagrangian approach, an alternative method is given by the Arbitrary Lagrangian Eulerian (ALE) formalism which consists in decoupling the motion of the material and the mesh. Starting from an initial guess of the sheet geometry between the rolls, the numerical simulation is performed until the stationary state is reached with a mesh, the nodes of which are fixed in the rolling direction but are free to move on perpendicular plane, following the geometrical boundary of the sheet. The whole forming line can then be modelled using a limited number of brick and contact elements because the mesh is only refined near the tools where bending and contact occur. In this paper, ALE results are compared to previous Lagrangian simulations and experimental measurement on a U-channel, including springback. Advantages of the ALE method are finally demonstrated by the simulation of a tubular rocker panel on a 16-stands forming mill.


2014 ◽  
Vol 939 ◽  
pp. 373-380 ◽  
Author(s):  
Peter Groche ◽  
Christian Mueller ◽  
Lars Baeumer

Roll forming is an important forming process for profile manufacturing in mass production. The design of the process has an important influence on the quality of the products. Therefore, the knowledge of the occurring loads during the roll forming process, e.g. forces and pressures, is essential for the process design. However, the experimental determination of the occurring contact normal pressures in roll forming processes poses a challenge. Finite element simulations offer the potential to approximate contact normal loads and thus, enable a better process design. Nevertheless, due to simplifications of the numerical model, a realistic and reliable output of loads in roll forming is not possible. An enhanced numerical model could provide more valuable information. This paper will demonstrate the reproduction of realistic contact normal pressures and load forces in a roll forming simulation. To verify the numerical values, they will be compared to data gained by experiments.


2013 ◽  
Vol 25 (s) ◽  
pp. 106-110
Author(s):  
崔鼎 Cui Ding ◽  
苏友斌 Su Youbin ◽  
崔云俊 Cui Yunjun ◽  
鲜玉强 Xian Yuqiang ◽  
张伟 Zhang Wei

2014 ◽  
Vol 611-612 ◽  
pp. 436-443 ◽  
Author(s):  
Christian Mueller ◽  
Xun Gu ◽  
Lars Baeumer ◽  
Peter Groche

Roll forming is an important economic forming process for manufacturing of profiles. For an optimal design of the process, it is important to determine the loads occurring during the forming process. Furthermore, the information of the load behavior enables an evaluation of the formability of the planned profiles with the chosen roll forming machine. An experimental determination of loads in roll forming processes requires a complex measurement setup in combination with a high amount of measurement devices. Hence, the analysis of roll loads by means of finite element simulation is of special interest. The use of roll forming simulations for the determination of geometrical outputs is state of the art. However, due to simplifications, a realistic and reliable output of roll loads in roll forming is impossible. Therefore, the compliance behavior under load and the frictional behavior have to be incorporated in the simulation model. The friction behavior in roll forming processes is presented to be very insignificant in literature. The value of the friction coefficients vary in a broad range. Due to lack of knowledge in the compliance behavior of the used stands, simulation models with rigid rolls are still state of the art. This paper will show the reproduction of realistic roll loads, e.g. torques and forces, in a roll forming simulation. Therefore, the friction coefficients of each roll-sheet metal contact will be gained experimentally and implemented in the numerical model. Furthermore, a characteristic compliance of the roll forming stands will be analyzed and also considered in the simulation. Finally, the influence of changing parameters, e.g. raise of the friction coefficients, on the roll loads will be investigated. To verify the simulation the numerical results will be compared to data gained by experiments.


2015 ◽  
Vol 789-790 ◽  
pp. 116-120
Author(s):  
Dong Hong Kim ◽  
Hao Yu ◽  
Dong Won Jung

This study, based on finite element analysis, analyzed the spring back phenomenon and stress distribution of forming sheets (HTS) in the roll forming process. By comparison of the stress distribution, this study analyzed two kinds of simulation. The first simulation performed simple bending simulation before roll forming simulation. With reference to the first simulation results, the second simulation analyzed the relationship between the stress distribution and the phenomenon of spring back. We also studied the stress distribution effect for spring back in the forming sheet.


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