Theoretical Investigation of the Bending Process of the Pre-Strained Metal Sheet

2020 ◽  
Vol 299 ◽  
pp. 351-357
Author(s):  
Sergey A. Tipalin ◽  
Michael A. Petrov ◽  
Yuriy A. Morgunov
Keyword(s):  
Thin Sheet ◽  
Bending Moment ◽  
Metal Sheet ◽  
Roll Forming ◽  
Forming Process ◽  
Bending Process ◽  
Punch Radius ◽  
Zero Radius ◽  
Strain Stress ◽  
Roll Forming Process

During the bending operation of the thin sheet materials by the punch with the near-to-zero radius the special technological operation should be carried out. It means that the metal sheet obtained a certain thinning value, which is usually done in the form of the channel-concentrator or groove by pre-drawing operation in a cold state. It follows to the pre-straining and strengthening of the material. The authors investigated the strain hardened sheet's area after roll forming process theoretically, and obtained the strain-stress distribution inside the sheet during the bending operation. It was found out that the increase of the prior deformation during pre-straining in the bend layer follows to the increase of the radial and tangential stresses and displacement of the neutral axis inside the blank during bending operation. As a result, the bending moment changes its values depends on the punch radius and strain hardening.

Quadrilateral Shape Rib Forming by Roll Forming Process

2018 ◽  
Vol 878 ◽  
pp. 296-301
Author(s):  
Dong Won Jung
Keyword(s):  
Automotive Industry ◽  
High Strength Steel ◽  
Numerical Study ◽  
Thickness Distribution ◽  
High Strength ◽  
Metal Sheet ◽  
Product Performance ◽  
Roll Forming ◽  
Forming Process ◽  
Roll Forming Process

The roll forming is one of the simplest manufacturing processes for meeting the continued needs of various industries. The roll forming is increasingly used in the automotive industry to form High Strength Steel (HSS) and Advanced High Strength Steel (AHSS) for making structural components. In order to reduce the thinning of the sheet product, traditionally the roll forming has been suggested instead of the stamping process. The increased product performance, higher quality, and the lowest cost with other advantages have made roll forming processes suitable to form any shapes in the sheets. In this numerical study, a Finite Element Method is applied to estimate the stress, strain and the thickness distribution in the metal sheet with quadrilateral shape, ribs formed by the 11 steps roll forming processes using a validated model. The metal sheet of size 1,000 × 662 × 1.6 mm taken from SGHS steel was used to form the quadrilateral shape ribs on it by the roll forming process. The simulation results of the 11 step roll forming show that the stress distribution was almost uniform and the strain distribution was concentrated on the ribs. The maximum thinning strain was observed in the order of 15.5 % in the middle rib region possibly due to the least degree of freedom of the material.

Comparison of Bending of Automotive Steels in Roll Forming and in a V-Die

2012 ◽  
Vol 504-506 ◽  
pp. 797-802 ◽  
Author(s):  
Matthias Weiss ◽  
Jascha Marnette ◽  
Preston Wolfram ◽  
Jon Larrañaga ◽  
Peter D. Hodgson
Keyword(s):  
Analytical Equation ◽  
Roll Forming ◽  
Cold Roll Forming ◽  
Forming Process ◽  
Cold Roll ◽  
Bending Process ◽  
Roll Forming Process ◽  
Springback Angle ◽  
Die Forming ◽  
Good Agreement

Bending in a V-die has been used to indicate the outcome of bending in cold roll forming, although little direct correlation has been performed. In this work direct comparison of the springback in both processes was performed using six samples of automotive steels in a conventional roll forming line where the transverse springback is measured. A bend of similar radius was formed in a V-die and the springback determined. In general, the springback in V-die forming was greater than in roll forming, in some cases by a factor of 2. The theoretical springback angle was determined for all steels using a simple and approximate analytical equation and compared to the experimental roll forming and bending results. While for the roll forming process good agreement was achieved the theoretical values significantly underestimated springback in the V-bending process.

Analysis of Flexible Roller Parameters Influences on Roll Forming of Three-Dimensional Parts

2014 ◽  
Vol 875-877 ◽  
pp. 450-454
Author(s):  
Jiao Jiao Zhen ◽  
Zhi Qing Hu ◽  
Zeng Ming Feng ◽  
Jun Hui Cao
Keyword(s):  
Three Dimensional ◽  
Roll Forming ◽  
Forming Process ◽  
Bending Process ◽  
Experimental Parameters ◽  
Flexible Roll ◽  
Roll Velocity ◽  
Set Up ◽  
Roll Forming Process

Roll forming is a well known bending process and sheet metals can only be machined into two-dimensional surfaces in traditional roll forming. While with more and more personalized demands, three-dimensional surfaces are widely required. Thus, flexible rollers are used to achieve three-dimensional surfaces. And in order to optimize experimental parameters and to predict experimental results, finite element method (FEM) is developed. In this paper the set-up of flexible roll-forming is described and the process of roll forming is simulated. Then the influences of forming parameters, such as the thickness and the roll velocity, on forming quality of the sheet metal in roll forming process are discussed. The results show that the analysis of flexible roller parameters is practical for the continuous and efficient forming of three-dimensional surfaces.

A New Engineering Technique in Roller Design to Prevent Thinning of Sheet in Roll Forming Process

2017 ◽  
Vol 873 ◽  
pp. 42-47
Author(s):  
Dong Won Jung
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Metal Sheet ◽  
Roll Forming ◽  
Forming Process ◽  
Explicit Finite Element ◽  
Main Challenge ◽  
Engineering Technique ◽  
Roll Forming Process

These days sheet metal forming is a widely used in different industrial fields with large production volumes. Formability of metal sheets is limited by localized necking and plastic instability. In sheet metal forming processes like drawing and stamping the main challenge is thinning of the metal sheet in some regions. To reduce thinning of the sheet product, roll forming has been suggested instead of stamping process. Thinning strain can cause necking, tearing or wrinkling which are failure of the metal sheet. In this study a new engineering technique is proposed in order to prevent thinning of the steel galvanized hot coil commercial (SGHC) in roll forming process. An explicit finite element code, ABAQUS software, was used to simulate the roll forming process. The results show that the proposed technique has an important effect on thinning of the sheet and can reduce it significantly. Investigation on the second and third and fourth rollers show the effect of modified roller dimension as on reducing the thickness. These reductions in second, third and fourth rollers are from 4 percent to 0.5 percent, 2.8 to 1.4 percent and from 1.4 to 0.7 percent respectively. The reasons of the new techniques effect were also discussed.

Investigation of a Geometrical Base Parameter Affecting on Bending Quality in a Thin Sheet Metal

2017 ◽  
Vol 728 ◽  
pp. 66-71
Author(s):  
Aran Blattler ◽  
Maitri Kamonrattanapisud ◽  
Thanasan Intarakumthornchai ◽  
Yingyot Aue-u-Lan
Keyword(s):  
Sheet Metal ◽  
Thin Sheet ◽  
Fem Simulation ◽  
Roll Forming ◽  
Forming Process ◽  
Bending Process ◽  
Thin Sheet Metal ◽  
Bending Radius

A geometrical base parameter is investigated to determine the effect on a bending quality of a thin sheet metal for a roll forming process. This parameter is usually used as a criterion for the quality control of incoming materials for the bending process. This study was conducted by using a FEM simulation. The determination of the geometrical base parameter is considered as an appropriate and unique characteristic for each type of materials. To find this geometrical base parameter the dimensions of the workpiece must be measured while loading. The sensitivity of the bend allowance of a sheet metal is dependent on this geometrical base parameter. The high geometrical base parameter is led to indicate the elongation and the strength of the material. The principles of the geometrical base parameter are dependent on several factors, such as the bending angle, bending radius, material thickness, bend allowance, bending types and mechanical properties of materials. The outcomes of this study could provide the information used to enhance the bend quality of the sheet metal.

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