An improved theoretical model of a metal tube under free external inversion

Qiu, Xin; He, Liang; Gu, Jie; Yu, Xianglong

doi:10.1016/j.tws.2014.02.025

Cited by 31 publications

(8 citation statements)

References 19 publications

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“…For comparison, the results of free inversion tubes given by Ref. [4] are also listed in Table 2. Here b is defined as 2b ¼ R e À R 0 À t 0 , the P is corresponding to die radius Here t 0 =R 0 ¼ 0:10 is taken as an example.…”

Section: Optimization Of Die Radiusmentioning

confidence: 99%

“…Based on energy conservation, predictions of knuckle radius and inversion force in the steady stage were obtained in very simple forms. This model was improved by subsequent studies; for example, the strain hardening of material was considered by Reddy [2]; a two-stage deformation assumption was proposed by Colokoglu and Reddy [3]; considering volume conservation, the velocity at the export point was changed by Qiu et al [4]. However, the predictions of the existing theoretical models of tube under free inversion all exhibit notable discrepancies compared with the experiments and FE simulations, both on steady inversion load and knuckle radius.…”

Section: Introductionmentioning

confidence: 99%

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Theoretical model of a metal tube under inversion over circular dies

Qiu

2016

International Journal of Mechanical Sciences

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Section: Optimization Of Die Radiusmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Theoretical model of a metal tube under inversion over circular dies

Qiu

2016

International Journal of Mechanical Sciences

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“…3.2 Simplified Theory of (Guist and Marble, 1966) The mean crushing force of circular tubes based on external free inversion process was investigated by a few studies (Guist and Marble 1966;Reddy, 1992;Colokoglu and Reddy, 1996;Qiu et al, 2014;andQiu et al, 2016). Firstly, Guist and Marble(1966) proposed a simplified theory to predict the steady-state inversion load of free inversion tube.…”

Section: I(w+s)small Tube = I(w+s)large Tube Simultaneous Inversionmentioning

confidence: 99%

“…Then, Colokoglu and Reddy(1996)further investigated the effects of strain rate and inertia during the dynamic free inversion process. Furthermore, Qiu et al(2014)modified Reddy's model to predict the knuckle radius and the steady inversion load during the external inversion process for aluminum circular tubes. Tomesani(1997)presented a modified way to conducted outside-in inversion process by using tension load at the inner wall instead of compression at the outer wall.…”

Section: Introductionmentioning

confidence: 99%

A New Configuration of Circular Stepped Tubes Reinforced with External Stiffeners to Improve Energy Absorption Characteristics Under Axial Impact

Zahran

Xue

Esa

et al. 2017

Lat. Am. j. solids struct.

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State-of-the art studies of impact crushing circular stepped tube (inversion tube) introduce various approaches to improve the energy absorption capacities. Adding external longitudinal stiffeners on the circular stepped tubes is a new approach that have a great effect and interest. In the current study, finite element analysis using (LS-DYNA/WORKBENCH ANSYS) is performed on a series of numerical models of aluminum circular stepped tubes that are externally stiffened by a constant number of longitudinal stiffeners distributed around the cross section of the circular stepped tube. The numerical models are implemented under an axial impact crushing scenario. Furthermore, a new improved formula for prediction of steady inversion load is proposed. The theoretical predictions are found to be in good agreement with the numerical results with an error within 12%. A comparative study is conducted to compare the energy absorption characteristics and inversion mechanism between the newly proposed tubes and the conventional stepped tube. The results showed that addition of external longitudinal stiffeners on circular stepped tubes could imply greatest improvement for the energy absorption up to 104%, specific energy absorption capability (energy absorption per unit mass) up to 54.9%, the crush force efficiency up to 40.3% and increase the inversion stroke length in comparison with the unstiffened circular stepped tubes. A newfound role of external longitudinal stiffeners added to the stepped tubes that controls the inversion and deformation mechanism is presented.

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“…As far as mass production is concerned, metal forming offers the most advantages due to short manufacturing time, low material waste and high strength properties. Metal forming techniques for producing hollow parts include: • spinning [1,2], • standard forging [3,4], • rotary swaging [5,6], • extrusion [7], • rotary compression [8,9], • flanging [10,11], • sequential upsetting [12], • radial extrusion.…”

Section: Introductionmentioning

confidence: 99%

Numerical and Experimental Study of Producing Two-Step Flanges by Extrusion with a Movable Sleeve

Winiarski¹,

Gontarz²

2017

Archives of Metallurgy and Materials

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The paper presents a new metal forming process for producing two-step external flanges on hollow parts. With this method, the flange is extruded by a movable sleeve, which moves in the opposite direction to the punch. This reduces the phenomenon of buckling of the tube wall, which allows extruding flanges with relatively large volumes. The new method was applied to produce a two-step flange on the end of a tubular billet made of 6060 aluminum alloy. This cold metal forming process was designed based on numerical simulations and experimental tests. The effect of the basic technological parameters on metal flow was investigated and limitations of the process were identified. The experimental results confirmed the possibility of forming a two-step flange with a diameter that is approximately twice as big as the external diameter of the tubular billet.

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An improved theoretical model of a metal tube under free external inversion

Cited by 31 publications

References 19 publications

Theoretical model of a metal tube under inversion over circular dies

Theoretical model of a metal tube under inversion over circular dies

A New Configuration of Circular Stepped Tubes Reinforced with External Stiffeners to Improve Energy Absorption Characteristics Under Axial Impact

Numerical and Experimental Study of Producing Two-Step Flanges by Extrusion with a Movable Sleeve

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