An upper bound analysis for reshaping thick tubes to polygonal cross-section tubes through multistage roll forming process

Cold roll forming is a process for plastic deformation, which allows realizing profiles, with a defined section and established length, from the plastic deformation of a metal sheet. The sheet is induced to cross several stands of rolls, arranged along the same axis of advancing. The rolls induce plastic deformation in the sheet and then lead it to the desired geometric configuration. In order to control the geometric parameters of the plate during the profiling, it was created a FEM model to simulate the final stage of the technological process, developed by an industrial production line of a company located in Naples (Italy), that sells tubes with several cross sections. In this phase, the semi-finished product, having a circular cross section, is forced to cross through four stands of rolls. In this way, it changes the geometric condition of the cross section from circular to square. The model was carried out using a non-linear calculation code, which allows analyzing the parameters of interest in the different process steps. The results, obtained numerically, were compared with the experimental ones through the measurement of five specimens, obtained directly from technological process. The values of percentage deviation, regarding the external dimension and the thickness, for each step of advancement, do not exceed the 3% of error. Then, the analysis results denote the capability to simulate the cold roll forming process using finite element method.

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A 3D FE Model for Roll Forming of Ring with Complex Cross Section

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.538-541.788 ◽

2012 ◽

Vol 538-541 ◽

pp. 788-791

Author(s):

Gang Yao Zhao ◽

Ran Yang Zhang ◽

Zheng Hua Guo ◽

Zhan Rong Feng ◽

Shuai Ying

Keyword(s):

Cross Section ◽

Equivalent Strain ◽

Roll Forming ◽

Fe Model ◽

Forming Process ◽

Geometry Modeling ◽

Complex Cross ◽

Complex Cross Section ◽

Materials Modeling ◽

Roll Forming Process

The roll forming process is a technique for forming ring with complex cross section, which widely used in the fields of aviation, aerospace and other high technology industries. To predict and control the roll forming quality, a 3D elastic-plastic finite element (FE) model of ring with complex cross section for roll forming was developed using the explicit code ABAQUS/Explicit. During the modeling process, several key techniques are solved, such as materials modeling, geometry modeling and grid optimal design. Then the reliability of the model was verified. Furthermore, numerical simulation and analysis of the roll forming process of ring with complex cross section have been carried out by using the model. The distribution regularities of equivalent strain in the process have been analyzed. The results show that with the progressing of roll forming, the equivalent strain increase sharply in the initial stage, then slightly varies, and the W shape of ring cross section is produced gradually.

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Upper Bound Analysis of the ECAE Process by Considering Strain Hardening Materials and Three-Dimensional Rectangular Dies

Journal of Manufacturing Science and Engineering ◽

10.1115/1.2844590 ◽

2008 ◽

Vol 130 (5) ◽

Cited By ~ 7

Author(s):

R. Luri ◽

C. J. Luis Pérez

Keyword(s):

Strain Hardening ◽

Cross Section ◽

Upper Bound ◽

Equal Channel Angular Extrusion ◽

Rectangular Cross Section ◽

Three Dimensional ◽

Plastic Deformations ◽

Material Parameters ◽

Upper Bound Analysis ◽

Bound Analysis

Equal channel angular extrusion (ECAE) or pressing is a process used to introduce severe plastic deformations to processed materials with the aim of improving their mechanical properties by reducing the grain size. At present, there are no analytical studies that have considered strain hardening materials in order to determine the required force to carry out the process. All the existing papers have only considered nonstrain hardening materials. Furthermore, all those studies have been done by considering plane strain conditions. In this work, an upper bound analysis of the required force for performing the ECAE process is made by considering a full three-dimensional geometry with a rectangular cross section. From this analysis, the influence of the geometric and the material parameters is studied by considering both friction and strain hardening materials. By using the upper bound method, an analytical formulation was obtained and the influence of all the parameters was determined. With this work, it is possible to have a wider knowledge of the influence of the main affecting parameters in the ECAE process and to optimize them.

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