On the determination of forming limits in thin-walled tubes

Magrinho, J.P.; Silva, M.B.; Centeno, Gabriel; Moedas, F.; Vallellano, C.; Martins, P.A.F.

doi:10.1016/j.ijmecsci.2019.03.020

Cited by 37 publications

(48 citation statements)

References 30 publications

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“…Thus, it can be directly applied to problems with non-negligible strain gradients as previously mentioned in [39]. Furthermore, [40] have shown the effectiveness of this methodology for determining the limits of formability in the case of thin-walled aluminum tubes. It should also be observed that the time-dependent average fits consist merely for both materials in a shift of the ISO-12004 curves both in the range of higher major and minor strains.…”

Section: Time Dependent Methodsmentioning

confidence: 87%

Development of a Nakazima Test Suitable for Determining the Formability of Ultra-Thin Copper Sheets

Ayachi

Guermazi

Pham

et al. 2020

Metals

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The objective is to propose an accurate method for determining the forming limit curves (FLC) for ultra-thin metal sheets which are complex to obtain with conventional techniques. Nakazima tests are carried out to generate the FLCs of a pure copper and a copper beryllium alloy with a thickness of 0.1 mm. Because of the very small thickness of the sheets, the standard devices and the know-how of this test are no longer valid. Consequently, new tools have been designed in order to limit friction effect. Two different methods are used and compared to estimate the necking: the position-dependent measurement method (ISO Standard 12004-2), and the time-dependent method based on the analysis of the derivatives of the planar strain field. It is shown that the ISO standard method underestimates the forming limit curves. As the results present non linear strain paths, a compensation method is applied to correct the FLCs for the tested materials, which combines the effects of curvature, nonlinear strain paths and pressure. The curvature effect for such thickness and punch diameter on the FLCs is weak. The results show that this procedure enables to obtain FLCs that are close to those determined by the reference Marciniak method, leading to a minimum in major strain that converges to the plane strain state.

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Section: Time Dependent Methodsmentioning

confidence: 87%

Development of a Nakazima Test Suitable for Determining the Formability of Ultra-Thin Copper Sheets

Ayachi

Guermazi

Pham

et al. 2020

Metals

View full text Add to dashboard Cite

show abstract

“…In other words, shell elements are suitable in case the through-thickness variations are not of interest. On the other hand, the capacity of solid elements is unlimited as the six independent stress components are all considered within the constitutive equation as shown in [7]. A comparison of using shell and solid elements for modeling the tube is shown in Figure 7.…”

Section: Mesh Settingsmentioning

confidence: 99%

“…Besides, one of the essential disciplines in the field of metal forming in general is the forming limit. Magrinho et al [7] have introduced a pioneer study of the determination of forming limits in thin-walled tubes. A method called digital image correlation (DIC) has been employed to predict the onset of failure by necking and also predict the corresponding strain limits.…”

Section: Introductionmentioning

confidence: 99%

Optimization of AL6061-T6 Tube End Forming Process Using Response Surface Method

Shaaban

Elsabbagh

2021

Modelling and Simulation in Engineering

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Tube end closing is a metal forming process that replaces welding processes while closing tubes ends. It depends on deforming a rotating tube using a roller, and therefore, it is also called tube end spinning. The process involves many parameters like contact depth, roller inclination angle, roller diameter, mandrel curvature, and tube rotational speed. This study develops a finite element model (FE-model) for this process and validates it through experimental results. The numerical and experimental results have shown minor deviation of 1.87%. The FE-model is then employed to carry out a statistical analysis based on the response surface method (RSM). The analysis of variance (ANOVA) and regression analysis have proved the accuracy of the obtained mathematical model. The contact depth has proved to have the most significant effect in the process responses, while the roller diameter has the least effect. Finally, an optimization analysis is carried out to select the finest conditions for the process.

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“…Methodology for determining deformability limit in thin-walled tubes forming process is presented in paper [2]. Rigid tools are used in the experiment.…”

Section: Introductionmentioning

confidence: 99%

Stability Analysis of Steel Welded Tubes Forming Process Using Numerical Simulations

Delić

Mandić

Popović

2021

Teh. glas. (Online)

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In this paper, the research results of the stability of steel welded tubes forming process are presented. The aim of this research is to determine influence of geometrical and tribological parameters on stability of the process and to determine optimal values of influential process parameters. A research plan with variation of influential parameters was made, on the basis of which experimental and numerical experiments were performed. Tube forming was performed in one operation in a two-part tool made of hard metal by a combination of widening and narrowing. The geometrical factors observed during experiments are length, outer diameter and thicknesses of steel welded tube as a billet. Friction conditions in contact between tool and tubular workpiece are considered in two cases, the first one when standard machine oil is used as a lubricant and the second one when tube billet surface is phosphated. Based on results of experiments, influencing factors on stability of tube forming process were analysed and optimal production technology was recommended, including optimal values of influencing factors. Results obtained by experimental research were confirmed through numerical experiments based on finite element method.

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On the determination of forming limits in thin-walled tubes

Cited by 37 publications

References 30 publications

Development of a Nakazima Test Suitable for Determining the Formability of Ultra-Thin Copper Sheets

Development of a Nakazima Test Suitable for Determining the Formability of Ultra-Thin Copper Sheets

Optimization of AL6061-T6 Tube End Forming Process Using Response Surface Method

Stability Analysis of Steel Welded Tubes Forming Process Using Numerical Simulations

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