Computer Application to the Visioplasticity Method

Shabaik, A. H.; Kobayashi, Shirô

doi:10.1115/1.3610050

Cited by 46 publications

(4 citation statements)

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“…In practice the yield stress is likely to be determined by a functional describing the history of plastic strain, temperature and time, and thus may depend on heat transfer to the die. 3 However, it also appears that the use of equations (5) and (6) does not in fact really require any assumption regarding the uniqueness of the strain hardening curve, as expressed in the formula 5 = f («, «)• Can the author confirm this opinion? Such information is essential in providing an insight into the mechanics of the forming process and to determine the final mechanical properties of the product, as for example, texture, anisotropy, and the state of residual stresses.…”

Section: J Hilliermentioning

confidence: 98%

Discussion: “Computer-Aided Visioplasticity Solution to Axisymmetric Extrusion Through Curved Boundaries” (Shabaik, A. H., 1972, ASME J. Eng. Ind., 94, pp. 1225–1230)

Hillier

1972

Journal of Engineering for Industry

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Section: J Hilliermentioning

confidence: 98%

Discussion: “Computer-Aided Visioplasticity Solution to Axisymmetric Extrusion Through Curved Boundaries” (Shabaik, A. H., 1972, ASME J. Eng. Ind., 94, pp. 1225–1230)

Hillier

1972

Journal of Engineering for Industry

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“…Apart from the total force required to achieve the forming process, the detailed stress and strain distributions within the deformation zone are required to optimize the process variables and avoid occurrence of defects. Shabaik and Thomsen [14] analysed specific problems of split axisymmetric extrusion of lead and aluminium using a computer-aided visioplasticity method. However, few analytical solutions dating back to 1947 [1] gave the stress distribution in the die zone.…”

Section: Introductionmentioning

confidence: 99%

Plastic flow in extrusion and drawing through conical and wedge-shaped dies: Prediction of central bursting

Samy

Saleh

Ragab

2006

Proceedings of the Institution of Mechanical Engineers, Part C:

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In this article, the plastic flowfields for extrusion and drawing - for rigid plastic materials forced through conical and wedge-shaped dies - are analysed on the basis of Shield's work. A modification to Shield's analysis is developed to account for the redundant deformation. Solutions for axisymmetric and plane strain flows are given. The total forces estimated for both drawing and extrusion operations are compared favourably with available experimental data. On the basis of the present modified Shield's analysis, expressions for the stresses within the die are then derived. These expressions are then employed to predict central bursting by applying two fracture criteria, namely: the hydrostatic stress criterion and the plastic instability criterion. The deformation zone geometry criterion has also been used for comparison. The predictions fairly agree with the experimental results.

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“…Based on the location of the distorted grid lines (in terms of radial and axial directions), values of the flow function of the metal were calculated. 11,18) A smoothing procedure developed by Shabaik 19) was employed in these results, allowing the determination of an analytical expression for the flow function. Subsequent calculations, involving the velocity, strain rate and strain components and the effective strain, were conducted through the classical method proposed by Thomsen.…”

Section: Visioplasticity Techniquementioning

confidence: 99%

“…The visioplasticity, also called incremental grid method, 8,9) was originally proposed by Thomsen,11) based on the establishment of a velocity vector field on the meridian plane of the metal, followed by the calculation of the complete distribution of strain rate, strain and stress. The process is carried out by placing a grid pattern in the internal plane surfaces of sectioned samples.…”

Section: Introductionmentioning

confidence: 99%

The Deformation and the Redundant Work Factor in the Axisymmetric Drawing of AISI 420 Stainless Steel Bars—Strain Path Effects Analysis

et al. 2008

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In the present work, experimental techniques for evaluating the deformation and the redundant work factor in the axisymmetric drawing of ferritic AISI 420 stainless steel bars were investigated. Six operation conditions, involving two reductions of area and three die semi-angles, were employed in the study. Regarding the redundant deformation analysis, the visioplasticity technique was considered as the most adequate procedure for estimating the average deformation in drawing. In this case, an increasing relationship between the redundant deformation factor and the parameter D was obtained. On the other hand, the stress-strain curves superposition technique led to redundant deformation factor values almost insensitive to variations of the parameter D and below unity, a phenomenon which was associated with strain path effects. Concerning the redundant work factor study, the experimental results were lower than those obtained through a theoretical approach and, in some conditions, below unity. This was also attributed to strain path effects.KEY WORDS: drawing; average strain; visioplasticity; redundant deformation factor; redundant work factor. 63© 2008 ISIJ ones, employing a previously obtained relationship between hardness and strain. This approach, however, is not evaluated in this work and, therefore, no details are given in the text. For more information see Refs. 4), 6), 9).The visioplasticity, also called incremental grid method, 8,9) was originally proposed by Thomsen,11) based on the establishment of a velocity vector field on the meridian plane of the metal, followed by the calculation of the complete distribution of strain rate, strain and stress. The process is carried out by placing a grid pattern in the internal plane surfaces of sectioned samples. As plastic deformation is conducted, the rate of distortion of the grid lines is evaluated, and subsequent analysis is performed employing equilibrium and plasticity equations. Therefore, contrasting with the stress-strain curves superposition and the hardness profile methods, the results obtained in visioplasticity are non-dependent of the measurement of the mechanical properties of the metal after the processing. In addition to providing detailed information concerning the forming operation, this technique may act as a kind of calibration procedure, whose results would be used for checking the accuracy of solutions obtained through other investigative methods. 14,15) On the other hand, even though the visioplasticity has been considered as the experimental procedure leading to the most realistic solutions to various processes, 11) the time consuming calculations and the requirement of smoothing procedures for treating the experimental data seem to have restrained the use of the method, seldom employed in recent investigations concerning metal forming operations. 12) In the case of axisymmetric drawing, as far as the present authors know, the analyses have been performed only for few materials and process parameters, 8,9) with no reference to the calculat...

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Computer Application to the Visioplasticity Method

Cited by 46 publications

References 0 publications

Discussion: “Computer-Aided Visioplasticity Solution to Axisymmetric Extrusion Through Curved Boundaries” (Shabaik, A. H., 1972, ASME J. Eng. Ind., 94, pp. 1225–1230)

Discussion: “Computer-Aided Visioplasticity Solution to Axisymmetric Extrusion Through Curved Boundaries” (Shabaik, A. H., 1972, ASME J. Eng. Ind., 94, pp. 1225–1230)

Plastic flow in extrusion and drawing through conical and wedge-shaped dies: Prediction of central bursting

The Deformation and the Redundant Work Factor in the Axisymmetric Drawing of AISI 420 Stainless Steel Bars—Strain Path Effects Analysis

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