FEM dynamic simulation and analysis of the roll-bending process for forming a conical tube

Continuous roller bending of plates is an effective process in the production of single seamed tubes of large and medium diameters. The process is capable of a wide range of various tube diameters from the smallest of just larger than the diameter of the top roller to the largest limited only by the handling capacity of the bender. It requires less investment in toolings compared to other bending processes. Relevant researches on roller-bending are reviewed and referred to. Current roller-bending machines are discussed. In particular, the versatility of the four-roll bender and its ability to generate better circularity, thereby helping to reduce material wastage and amount of subsequent machining, are examined. This paper discusses not only the design considerations, but also the working principles and some relevant bending mechanisms of the process.

Continuous four-roll plate bending: a production process for the manufacture of single seamed tubes of large and medium diameters

Sheet metal bending processes are some of the most commonly used industrial manufacturing operations. The development and optimization of these processes are time consuming and costly. Therefore, finite element simulations may aid the design and quality assurance of sheet metal products. In the present study, a commercial finite element package was used to analyze the three-roller bending of a steel sheet. A two-dimensional finite element model of this process was built under the ABAQUS/Explicit environment based on the solution of several key techniques, such as contact boundary condition treatment, material property definition, meshing technique, and so on. Maps with desired curvature radii were established by varying the distance between the two bottom rollers and the position of the upper one. The developed maps made the rolling process easier and less time consuming. An industrial experiment using optimized numerical results was carried out to validate the numerical model. Residual stress and equivalent plastic strain distributions were also studied. The numerical spring back phenomenon was compared with analytical results.

/pdf/modeling-and-computation-of-the-three-roller-bending-process-4uiq6dja24.pdf

Modeling and computation of the three-roller bending process of steel sheets

Roller bending process can be used to plastically deform a sheet or plate to hollow shapes of constant (i.e. cylindrical, elliptical) or varying (i.e. cone frustum) cross sections. Cylindrical and conical shells are the basic components of vessels and structures used for the various engineering applications. Reported work discuss the formulation of springback and machine setting parameters for continuous multi-pass bending of cone frustum on three-roller bending machines with non-compatible (cylindrical) rollers. Effect of change of flexural modulus during the deformation on springback prediction is analyzed. Effect of plate initial radius, number of bending passes and step interval for two successive bend radii on the springback is presented. Analytical results of multi-pass cone frustum bending were verified with the cone frustum bending experiments and found to be in good agreement. Work reported is expected to improve the accuracy and productivity by facilitating the fabrication engineers.

M. Hua

Papers

Bending mechanisms, experimental techniques and preliminary tests for the continuous four-roll plate bending process