The Effect of Flange Length on the Distribution of Longitudinal Strain during the Flexible Roll Forming Process

Woo, Young Yun; Kang, Pilgyu; Oh, Il Yeong; Moon, Young Hoon

doi:10.4028/www.scientific.net/msf.920.46

Cited by 3 publications

(2 citation statements)

References 5 publications

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“…JOO et al [27] studied the flexible roll forming process of variable cross-section profiles and analyzed the effect of geometrical parameters such as base section width, side wall height and flange width on the longitudinal strain. Woo et al [28] used FEM simulation and experiment to study the influence of profile flange length on the transverse distribution of longitudinal strain in flexible roll forming, and the result showed that the longitudinal strain and longitudinal bow decrease with increasing flange length for a trapezoid and a concave blank. Abeyrathna et al [29] researched the effect of process and part shape parameters on the peak longitudinal edge strain, longitudinal bow and spring back for three different advanced high-strength steel (AHSS) and Ultra High Strength Steel (UHSS) commonly used in automotive manufacturing.…”

Section: Introductionmentioning

confidence: 99%

A Method for Rapid Prediction of Edge Defects in Cold Roll Forming Process

Meng

Fang

2021

Mathematics

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In order to implement rapid prediction of edge defects in the cold roll forming process, a new analytical method based on the mean longitudinal strain of the racks is presented. A cubic spline curve with the parameters of the cumulative chord length is applied to fit the corresponding points and center points of different passes, and fitting curves are obtained. As the cold roll forming is micro-tension forming, the tensions between racks are ignored. Then the mean longitudinal strains between racks are obtained. By comparing the mean longitudinal strain between racks and the yield strain of the material, we can judge whether there are defects at the edges. Finally, the reasonableness of this method is illustrated and validated by an example. With this method, the roll forming effect can be quickly predicted, and the position where a greater longitudinal strain occurred can be determined. In order to prevent the defects, the deformation angles need to be modified when the result is beyond the yield strain. To further prove the correctness of the theory, the results of the analytical method are compared with the ones of the non-linear finite element software ABAQUS. The analytical results have the same trend as the finite element results. This method can provide useful guidance to the actual design process.

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Section: Introductionmentioning

confidence: 99%

A Method for Rapid Prediction of Edge Defects in Cold Roll Forming Process

Meng

Fang

2021

Mathematics

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“…Various models are available in the literature to predict the deformation for common shrink flanging or stretch flanging conditions [13] [12]. Previous work has revealed that common analytical models for shrink or stretch-flanging lead to a high deviation between the prediction and the experimental results for longitudinal strain in the flange [7][14] [15]. A recent study [16] has developed an advanced model to predict membrane/ longitudinal peak strains and strain distribution in a flexible roll-formed flange.…”

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confidence: 99%

Wrinkling compensation by Flexible Roll Forming a developable profile

Sreenivas

Abeyrathna²,

Rolfe³

et al. 2023

Preprint

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Flexible Roll Forming (FRF) can form complex shapes with variable cross-sections along the length from high-strength steel. Widespread application of the FRF process in automotive manufacturing is however limited due to wrinkling defects that occur in the flange. Flange wrinkling can be eliminated by reducing the required level of membrane deformation and compressive stresses that develop in the longitudinal direction. This is conventionally achieved by reducing the severity of the transition regions but also limits the overall complexity of the parts that can be formed. Developable profiles can be created from curved creased folding without membrane stretching or compression. In FRF, such types of profiles can be formed by combining a variation in width and depth over the length of the part. This reduces the required longitudinal deformation while at the same time providing shape complexity. This study presents, for the first time, the analyses of forming a developable shape in a FRF operation. For this, first analytical equations are applied to calculate the deformation and forming stability of a developable component and of a reference variable depth component without a developable shape. This is followed by experimental FRF trials and shape deviation analysis for both forming conditions. Finally, Finite Element Analysis is used to investigate the forming behaviour of the two types of developable profiles. The results indicate that the forming of a surface developable can reduce wrinkling issues in the FRF process. However, the intermediate forming stages are non-developable, and this can lead to longitudinal compression and wrinkling issues that, if too severe, remain in the flange when the final developable shape is formed.

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