Twisting analysis of ultra-thin metallic sheets

Pham, Cong Hanh; Thuillier, Sandrine; Manach, Pierre‐Yves

doi:10.1016/j.jmatprotec.2013.12.006

Cited by 20 publications

(55 citation statements)

References 17 publications

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“…Wrinkling, tearing and excessive springback are the major defects arising in sheet metal forming processes [1,2]. Due to aesthetic and/or functional reasons, wrinkling is typically undesired in finished sheet metal parts.…”

Section: Introductionmentioning

confidence: 99%

Numerical and experimental analysis of wrinkling during the cup drawing of an AA5042 aluminium alloy

et al. 2015

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The recent trend to reduce the thickness of metallic sheets used in forming processes strongly increases the likelihood of the occurrence of wrinkling. Thus, in order to obtain defect-free components, the prediction of this kind of defect becomes extremely important in the tool design and selection of process parameters. In this study, the sheet metal forming process proposed as a benchmark in the Numisheet 2014 conference is selected to analyse the influence of the tool geometry on wrinkling behaviour, as well as the reliability of the developed numerical model. The side-wall wrinkling during the deep drawing process of a cylindrical cup in AA5042 aluminium alloy is investigated through finite element simulation and experimental measurements. The material plastic anisotropy is modelled with an advanced yield criterion beyond the isotropic (von Mises) material behaviour. The results show that the shape of the wrinkles predicted by the numerical model is strongly affected by the finite element mesh used in the blank discretization. The accurate modelling of the plastic anisotropy of the aluminium alloy yields numerical results that are in good agreement with the experiments, particularly the shape and location of the wrinkles. The predicted punch force evolution is strongly influenced by the friction coefficient used in the model. Moreover, the two punch geometries provide drawn cups with different wrinkle waves, mainly differing in amplitude.

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Section: Introductionmentioning

confidence: 99%

Numerical and experimental analysis of wrinkling during the cup drawing of an AA5042 aluminium alloy

et al. 2015

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“…To realize the various applications in the aerospace industry, the demand for bent profile parts usually with large scales and shapes differs in various bending angles/radii and geometric cross-section are mainly produced by roll bending process [3,4]. However, similar to sheet metal bending, non-uniform deformation inevitably occurs during bending, viz., tension at the extrados and compression at the intrados of the bending profiles and also a certain degree of twist often occurs during the roll bending process [5,6]. This phenomenon even behaves more obvious for the profiles with asymmetrical section characteristics and can be defined as twist springback or twist defects, which significantly affects the dimensional accuracy and geometrical properties of the product [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Analysis and Control of Twist Defects of Aluminum Profiles with Large Z-Section in Roll Bending Process

Wang

Xue

Bayraktar

et al. 2019

Metals

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This paper focuses on the twist defects and the control strategy in the process of four-roll bending for aluminum alloy Z-section profiles with large cross-section. A 3D finite element model (3D-FEM) of roll bending process has been developed, on the premise of the curvature radius of the profile, the particularly pronounced twist defects characteristic of 7075-O aluminum alloy Z-section profiles were studied by FE method. The simulation results showed that the effective control of the twist defects of the profile could be realized by adjusting the side roller so that the exit guide roll was higher than the entrance one (the side rolls presented an asymmetric loading mode with respect to the main rolls) and increasing the radius of upper roll. Corresponding experimental tests were carried out to verify the accuracy of the numerical analysis. The experimental results indicated that control strategies based on finite element analysis (FEA) had a significant inhibitory function on twist defects in the actual roll bending process.

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“…[29] The objective of this study is to characterize the behavior of an ultra-thin stainless steel of 0.15-mm thickness in order to investigate twisting phenomenon by finite element simulation. [30,31] For this objective, conventional tests such as tensile and simple shear tests were performed very carefully and with necessary adaptations due to the small thickness. The influence of the sample width on the stress level and fracture strain was investigated by using two different standards of test specimen, i.e., ASTM E8 and ISO 6892-1.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Properties Involved in the Micro-forming of Ultra-thin Stainless Steel Sheets

Pham

Thuillier

Manach

2015

Metall Mater Trans A

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The objective of this paper is to characterize the mechanical behavior of an ultra-thin stainless steel, of 0.15-mm thickness, that is commonly used in the manufacturing of miniature connectors. The main focus is the relationship between some microstructural features, like grain size and surface roughness, and the macroscopic mechanical behavior investigated in uniaxial tension and simple shear. In tension, adaptations to the very small sheet thickness, in order to hold the specimen under the grips, are presented. Yield stress, initial elastic modulus, and evolution of the loading-unloading slope with plastic deformation were evaluated. Moreover, the kinematic contribution to the hardening was characterized by monotonic and cyclic simple shear test and reproduced by a mixed hardening law implemented in Abaqus finite element code. Then, the evolution of surface roughness with plastic strain, both in tension and simple shear, was analyzed. It was shown that in the case of an ultra-thin sheet, the stress levels, calculated either from an average thickness or when considering the effect of the surface roughness, exhibit a significant difference. Finally, the influence of surface roughness on the fracture of a tensile specimen was also investigated.

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Twisting analysis of ultra-thin metallic sheets

Cited by 20 publications

References 17 publications

Numerical and experimental analysis of wrinkling during the cup drawing of an AA5042 aluminium alloy

Numerical and experimental analysis of wrinkling during the cup drawing of an AA5042 aluminium alloy

Analysis and Control of Twist Defects of Aluminum Profiles with Large Z-Section in Roll Bending Process

Mechanical Properties Involved in the Micro-forming of Ultra-thin Stainless Steel Sheets

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