Effects of process variables on V-die bending process of steel sheet

Huang, You–Min; Leu, Daw-Kwei

doi:10.1016/s0020-7403(97)00083-0

Cited by 50 publications

(31 citation statements)

References 6 publications

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“…The significant effect of D is also experimentally verified in Tekaslan et al (2008) and Osman et al (2010). Moreover, experimental results reported in Tekaslan et al (2006Tekaslan et al ( , 2008 and Huang and Leu (1998) for the main angle confirm the importance of the bending radius R 1 , material thickness M, and bending angle α. Lastly, the importance of material properties σ y is experimentally verified in Osman et al (2010). Varying the dimension of the punch L 1 is not considered in these experimental works although Fig.…”

Section: Modeling and Sensitivity Analysissupporting

confidence: 52%

Sequential robust optimization of a V-bending process using numerical simulations

Wiebenga

Boogaard

Klaseboer

2012

Struct Multidisc Optim

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The coupling of finite element simulations to mathematical optimization techniques has contributed significantly to product improvements and cost reductions in the metal forming industries. The next challenge is to bridge the gap between deterministic optimization techniques and the industrial need for robustness. This paper introduces a generally applicable strategy for modeling and efficiently solving robust optimization problems based on time consuming simulations. Noise variables and their effect on the responses are taken into account explicitly. The robust optimization strategy consists of four main stages: modeling, sensitivity analysis, robust optimization and sequential robust optimization. Use is made of a metamodel-based optimization approach to couple the computationally expensive finite element simulations with the robust optimization procedure. The initial metamodel approximation will only serve to find a first estimate of the robust optimum. Sequential optimization steps are subsequently applied to efficiently increase the accuracy of the response prediction at regions of interest containing the optimal robust design. The applicability of the proposed robust optimization strategy is demonstrated by the sequential robust optimization of an analytical test function and an industrial V-bending process. For the industrial application, several production trial runs have been performed to investigate and validate the robustness of the production process. For both applications, it is shown that the robust optimization strategy accounts for the effect of different sources of uncertainty onto the process responses in a very efficient manner. Moreover, application of the methodology to the industrial V-bending process results in valuable process insights and an improved robust process design.

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Section: Modeling and Sensitivity Analysissupporting

confidence: 52%

Sequential robust optimization of a V-bending process using numerical simulations

Wiebenga

Boogaard

Klaseboer

2012

Struct Multidisc Optim

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“…It is clear, that although both experimental and numerical tests have been carried out by Huang and Leu [79], the present 3D results are more accurate in most parts of the force-displacement plot. The analysis took 88 time steps with automatic step size selection.…”

Section: V-die Bending Of a Steel Sheetmentioning

confidence: 66%

“…This example is taken from a detailed paper about V-die bending [79] of steel sheets. The present analysis is carried out using 3D elements, whereas in the above reference 2D plane strain elements were adopted.…”

Section: V-die Bending Of a Steel Sheetmentioning

confidence: 99%

Algorithms for the analysis of 3D finite strain contact problems

Areias

Sá

Curnis

2004

Numerical Meth Engineering

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SUMMARYFrom the constraint imposition aspects in 3D to friction regularization, various ideas are exposed in this paper. A variation of the Rockafellar Lagrangian is proposed which results in continuous second-order derivatives if Lagrange multiplier estimates are greater or equal than one. This fact allows the adoption of a full second-order (i.e. Lagrange-Newton) method avoiding sequential unconstrained minimization techniques. An algorithm for global and local contact detection is presented which is developed for dealing with large step sizes typical of implicit methods. A modified constraint definition to deal with non-smooth situations is presented. Aspects of friction implementation, including a regularization scheme which ensures stepwise objectivity, are detailed. Finally, several illustrative examples are carried out with success.

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“…8) taken from [8], is a typical metalforming steels. It presents an hardening behaviour which follows the Swift's law, and since the final stress-strain result is expressed by the same law (15), for this steel a numeric comparison of the Swift's parameters is also possible.…”

Section: Resultsmentioning

confidence: 99%

“…As a matter of fact, the procedure does not stop until two consecutive calculations of C and e present approximately the same results. It should be highlighted that the two described phases need the calculation of all the angles θ i (i = 1.4), and this is possi- Relations (8) and (9) are written for two couples of measurements and give the problem solution in term of parameters C and e describing the bending moment-curvature law corresponding analytically to the two measurements taken. Obviously, it is necessary to consider more than two measurements, and the best experimented method to obtain a good agreement between identified results and FEM data is to repeat the determination of C and e using different zones of the force-penetration curve coming from the process.…”

Section: Multi-joint Modelmentioning

confidence: 99%

Identification of elasto-plastic characteristics by means of air-bending test

Antonelli

Salvini

Vivio

et al. 2007

Journal of Materials Processing Technology

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A new identification method of material elasto-plastic characteristics by means of simple testing is proposed. The outcome of the procedure is the true-stress versus true-strain curve. The result is proposed in analytical form, according to Swift's law. The method requires acquisition of actual force-penetration values, carried out during a standard air-bending test. One of the main advantage of this method is that it allows an immediate identification of the material behaviour just in-process, that is to say that material characteristics can be accounted differently for each sheet subjected to bending; this is a fundamental preliminary step to achieve a bending adaptive control of sheets. Input requirements for identification include the geometry of tools and sheet, and the friction coefficient between sheet and die which needs to be estimated previously. In the proposed method, at a first stage the bending moment-curvature curve for the sheet is obtained by the numerical computation of force-penetration data through a multi-joint model of sheet during air-bending. Then, a simplified bending model, characterized by linear strain distribution across the thickness and plane-stress assumption, is employed to calculate the stress-strain curve.

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Effects of process variables on V-die bending process of steel sheet

Cited by 50 publications

References 6 publications

Sequential robust optimization of a V-bending process using numerical simulations

Sequential robust optimization of a V-bending process using numerical simulations

Algorithms for the analysis of 3D finite strain contact problems

Identification of elasto-plastic characteristics by means of air-bending test

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