A variational upper-bound method for analysis of upset forging of rings

Yeh, Wei Ching; Wu, Ming Chang

doi:10.1016/j.jmatprotec.2005.06.007

Cited by 19 publications

(26 citation statements)

References 23 publications

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“…(16)- (19) are still valid for this case, but the natural ones, as shown in Eqs. (14) and (15) reflecting the interfacial friction conditions, must be replaced by …”

Section: Variational Approachmentioning

confidence: 99%

“…(1) and (2) are of kinematically admissible, and the means used for the purpose of minimization is based on the ordinary calculus. The upper-bound solution determined in this way does not account for the natural boundary conditions of the velocity field as considered in Yeh and Yang [3][4][5] and Yeh and Wu [14]. In the work of Yeh and Yang [3][4][5], the method that uses a variational approach to aim at determining the upper-bound solution is proposed, and is termed the variational upperbound (VUB) method.…”

Section: Introductionmentioning

confidence: 99%

“…The upper-bound solution is then determined by minimizing the upper-bound equation with respect to free parameters included in the chosen velocity field, that in the meantime satisfies not only all the kinematic boundary conditions, but also, if possible, the natural boundary conditions which cannot be obtained perceivably. It has been shown by Yeh and Yang [3][4][5] and Yeh and Wu [14] that due to the natural boundary condition imposed, the upper-bound solution reflects more precisely and reasonably in predicting the pattern of metal flow and the calculated total forming load for the planestrain and upsetting forging problems.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effect of natural boundary conditions on the upper-bound analysis of upset forging of ring and disks

Wu¹,

Yeh²

2007

Materials & Design

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“…(16)- (19) are still valid for this case, but the natural ones, as shown in Eqs. (14) and (15) reflecting the interfacial friction conditions, must be replaced by …”

Section: Variational Approachmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of natural boundary conditions on the upper-bound analysis of upset forging of ring and disks

Wu¹,

Yeh²

2007

Materials & Design

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“…Chandra and Srivastava [27] investigated the axisymmetric upsetting by using boundary element analysis to evaluate the ring compression test results. Yeh and Wu [28] studied the upsetting of rings. They used a variational upper-bound (VUB) model which was neglected in the traditional upper bound method to predict the barrelling profile of the upset ring and also the total forming energy rate.…”

Section: Introductionmentioning

confidence: 99%

A numerical study for prediction of forming load and experimental verification of bimetallic disc upsetting

Ayer

2017

Teh. vjesn.

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Original scientific paper Forming of disc samples composed from aluminium and copper in performed study was examined with upsetting procedure. An approach for prediction deformation load of upsetting processes is developed. This study combines the finite element method model, neural network model and upper bound method to simulate and predict the deformation load in upsetting of bimetallic materials. The Finite Element Method (FEM) results were obtained from DEFORM-3D software and they were compared and validated with experiments by taking forming load into consideration. Also, Artificial Neural Network (ANN) model was used to analyze and predict the forming load for different process parameters. The Upper Bound (UB) model was also proposed to estimate the forming load and the results were compared with experiments. It was understood that calculated results were in concordance with experimental results in upsetting of bimetallic hollow discs. Thus, proposed ANN, FEM and UB models provide a valuable insight into the parameters affecting forming load and can be named as useful tools to predict the forming load without the need of any experiments. Keywords: artificial neural network (ANN); bimetallic materials; DEFORM-3D; finite element method (FEM); load analysis; upper bound method (UB); upsetting Numerička analiza za predviđanje nastalog opterećenja i eksperimentalna provjera sabijanja bimetalnog diskaIzvorni znanstveni članak U ovom je istraživanju postupkom sabijanja ispitivano nastajanje pločastih uzoraka sastavljenih od aluminija i bakra. Razvijen je pristup za predviđanje opterećenja koje dovodi do deformacije u postupku sabijanja. U radu se kombinira model metode konačnih elemenata, neuronske mreže i metode gornje granice (upper bound) u svrhu simuliranja i predviđanja opterećenja koje dovodi do deformacije u postupku sabijanja bimetalnih materijala. Rezultati metode konačnih elemenata (FEM) dobiveni su softverom DEFORM-3D te su uspoređeni i provjereni na eksperimentima uzimajući u obzir stvoreno opterećenje. Primijenio se i model Umjetne Neuronske Mreže (Artificial Neural Network -ANN) za analizu i predviđanje nastalog opterećenja kod različitih parametara postupka. Za procjenu nastalog opterećenja predložen je i Upper Bound (UB) model, a rezultati su eksperimentalno uspoređivani. Ustanovilo se da su dobiveni rezultati u skladu s eksperimentalnima u sabijanju bimetalnih šupljih diskova. Prema tome, predloženi ANN, FEM i UB modeli pružaju dragocjen uvid u parametre koji utječu na stvaranje opterećenja i može ih se smatrati korisnim alatima za predviđanje stvaranja opterećenja bez potrebe bilo kakvih eksperimenata. Ključne

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“…5 When the ring specimen is compressed under a fixed condition, the ring will produce an interface from which the metal flows to both inside and outside directions. A study using the indefinite integrals upper bound method in the ring compression process shows that the method can clearly give natural boundary conditions which conventional method neglects, 6 and accurately predicts the interface position and deformation law of billet shape in the compression process.…”

Section: Introductionmentioning

confidence: 99%

Deformation behavior in the compression process of L-shaped aluminum alloy components

Liang

et al. 2011

JOM

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How would you……describe the overall significance of this paper? In order to discover the deformation mechanism in compression, L-shaped components of aluminum alloy are taken as specimen to investigate the influence of metal flow and deformation behavior in the forming process....describe this work to a materials science and engineering professional with no experience in your technical specialty? Research reports covering aspects of deformation in compression are mostly limited to simple cylinders or ring billets from above. As lightweight alloy requirements in the manufacture area increase, the proportion of the special shape aluminum alloy significantly increases. …describe this work to a layperson?The paper investigates deformation behavior in the compression process of L-shaped aluminum alloy, and verifies the technological experiments results. A theory has been established for 7075 L-shaped aluminum alloy compression deformation behavior research and developed for making a special billet compression deformation plan of large complex components in the prefabricated working procedure.In order to discover the deformation mechanism in compression, L-shaped components of aluminum alloy are taken as specimen to investigate the influence of metal flow and deformation behavior in the forming process. Research results show that when the sectional shape is fixed, the range of plastic zone in the deformation body is expanded with the increase of the height of the billet. In addition, the deformation billet has a tendency to change from convexity both inside and outside to convexity inside outside and concavity outside inside, and the complexity degree of deformation also increases. Flow interface in the deformation body deviates along the radial direction to the inside billet gradually. Moreover, when the height of billet is a constant, the flow interface disappears and the metal on the deformation billet has an outflow tendency entirely. The results agree with the numerical simulation through experiments verification.

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A variational upper-bound method for analysis of upset forging of rings

Cited by 19 publications

References 23 publications

Effect of natural boundary conditions on the upper-bound analysis of upset forging of ring and disks

Effect of natural boundary conditions on the upper-bound analysis of upset forging of ring and disks

A numerical study for prediction of forming load and experimental verification of bimetallic disc upsetting

Deformation behavior in the compression process of L-shaped aluminum alloy components

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