Plastic instability and growth of grooves and patches in plates or tubes

Duncombe, E.

doi:10.1016/0020-7403(72)90087-2

Cited by 35 publications

(7 citation statements)

References 5 publications

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“…Theoretical analysis for FLD was first developed on the basis of bifurcation analysis and incremental plasticity theory for a geometrically perfect and rate-independent sheet metal under uniform plane stress conditions [1][2]. Another approach, the so-called M-K method, postulates that localized necking initiates from a pre-existing geometrical or material imperfection [4], In most cases, the M-K approach underestimates the limit strain for experimental data [5][6]. When both principal strains are positive, it predicts infinite ductility, which is contradicted with experimental results.…”

Section: Introductionmentioning

confidence: 99%

The Strain Gradient Approach for Deformation Localization and Forming Limit Diagrams

Wang¹,

Majlessi²,

Ning³

et al. 1996

Journal of the Mechanical Behavior of Materials

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The strain gradient approach is incorporated into the M-K method for the deformation localization analysis and the prediction of the forming limit diagram (FLD) during sheet metal forming. This approach introduces an internal length scale into conventional constitutive equations and takes into account the effects of deformation inhomogeneity. It thus overcomes the imperfection sensitivity encountered in the conventional M-K method. The comparison between experimental and theoretical results for FLDs as predicted by different methods, indicates that the present approach is most suitable for these problems.The Strain Gradient Approach for Deformation Localization deformation states close to plane strain condition but overestimates it in the region near equi-biaxial stretching (εj = εImprovements to the M-K approach have been made in order to obtain better agreement with

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Section: Introductionmentioning

confidence: 99%

The Strain Gradient Approach for Deformation Localization and Forming Limit Diagrams

Wang¹,

Majlessi²,

Ning³

et al. 1996

Journal of the Mechanical Behavior of Materials

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“…For many metals, strain hardening and strain rate hardening contribute to producing the observed deformation. A constitutive law is given by Duncombe [62] σ…”

Section: The Influence Of Strain Hardening and Strain-rate Sensitivity On Elongationmentioning

confidence: 99%

Tensile Plasticity of Miniature Specimens for a Low Alloy Steel Investigated by Digital Image Correlation Technique

Yang

Wang

Song

et al. 2021

steel research int.

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Miniature specimens are widely being used to determine tensile properties of various size-limited new materials, especially quickly evaluate or monitor changes in mechanical properties of in-service reactor components to ensure their continuous operation with large safe margins. Although tensile properties of the miniature specimens are investigated extensively, the basic mechanism on such size effects, especially tensile plasticity, is not understood well. Here, tensile properties of A588 low alloy steel specimens with different gauge lengths and thicknesses are systematically investigated in situ using the digital image correlation technique. The findings reveal that the increase in the post-necking elongation with decreasing the specimen gauge length and the decrease with decreasing the specimen thickness are due to the scale-dependent strain-rate sensitivity, whereas the constant uniform elongation is attributed to the stable strain hardening exponent. An empirical formula on the relationship between the total elongation and the strain-rate sensitivity is proposed to describe the basic mechanism behind the specimen size-dependent elongation.

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“…[17,18], while Xing and Wang set up the relationship between the instability parameter I and the parameters of the material microstructure based on numerous experimental results, for use in the prediction of the presence and the development of superplastic instability caused by necks and cavities, and in helping others to choose the optimum mode of deformation and a reasonable strain rate to meet practical requirements [21,22]. [17,18], while Xing and Wang set up the relationship between the instability parameter I and the parameters of the material microstructure based on numerous experimental results, for use in the prediction of the presence and the development of superplastic instability caused by necks and cavities, and in helping others to choose the optimum mode of deformation and a reasonable strain rate to meet practical requirements [21,22].…”

Section: Superplastic Instability (Optimal Mode Of Superplastic Deformentioning

confidence: 99%

“…(16)- (18) with finite element analysis [25]. Experiments have demonstrated the cavitation has no obvious influence on the parts when its fraction is less than 0.01.…”

Section: Cavity Growth and Its Control Using Back-pressurementioning

confidence: 99%