Theoretical Study of the Dynamic Tensile Test

Regazzoni, G.; Johnson, J. N.; Follansbee, P.S.

doi:10.1115/1.3171805

Cited by 58 publications

(13 citation statements)

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“…There have been a number of attempts to capture the effect of inertia on neck development using simplified one-dimensional models (Regazzoni et al, 1986;Tuggu et al, 1990). Here, a two-state model is …”

Section: Two-state Model For Dynamic Neck Developmentmentioning

confidence: 99%

Material aspects of dynamic neck retardation

Xue

Vaziri

Hutchinson

2008

Journal of the Mechanics and Physics of Solids

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Neck retardation in stretching of ductile materials is promoted by strain hardening, strain-rate hardening and inertia. Retardation is usually beneficial because necking is often the precursor to ductile failure. The interaction of material behavior and inertia in necking retardation is complicated, in part, because necking is highly nonlinear but also because the mathematical character of the response changes in a fundamental way from rate-independent necking to rate-dependent necking, whether due to material constitutive behavior or to inertia. For rate-dependent behavior, neck development requires the introduction of an imperfection, and the rate of neck growth in the early stages is closely tied to the imperfection amplitude. When inertia is important, multiple necks form. In contrast, for rate-independent materials deformed quasi-statically, single necks are preferred and they can emerge in an imperfection-free specimen as a bifurcation at a critical strain. In this paper, the interaction of material properties and inertia in determining neck retardation is unraveled using a variety of analysis methods for thin sheets and plates undergoing plane strain extension. Dimensionless parameters are identified, as are the regimes in which they play an important role. r

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Section: Two-state Model For Dynamic Neck Developmentmentioning

confidence: 99%

Material aspects of dynamic neck retardation

Xue

Vaziri

Hutchinson

2008

Journal of the Mechanics and Physics of Solids

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“…Relying on the seminal work of Regazzoni et al (1986), we develop a simple finite difference model to describe the mechanical response of steel bars subjected to dynamic tension. Our explicit numerical approach lies within the spirit of the scheme recently developed by Kudryashov et al (2015) to investigate the onset and development of shear bands in metallic solids subjected to dynamic loading.…”

Section: Finite Difference Modelmentioning

confidence: 99%

“…The numerical studies on the dynamic necking problem started in the late 1980s and early 1990s with the pioneering works of Regazzoni et al (1986), Needleman and co-workers (Tvergaard and Needleman, 1990;Needleman, 1991;Knoche and Needleman, 1993) and Nemes and Eftis (1993). One advantage of the numerical calculations is that, unlike the linear stability analyses, they allow us to investigate the spatio-temporal development of the instability.…”

Section: Introductionmentioning

confidence: 98%

Necking evolution in dynamically stretched bars: New experimental and computational insights

Vaz-Romero

Rotbaum

Rodríguez-Martínez

et al. 2016

Journal of the Mechanics and Physics of Solids

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a b s t r a c tThis paper presents new results on dynamic neck evolution in steel bars of varying diameters. Dynamic tensile tests were carried out in a Kolsky apparatus using cylindrical steel specimens with various cross-section diameters ranging from 1.5 mm to 4 mm. A high speed digital camera was used to record the deformation of the specimen during the loading process. Video recording of the tests enabled accurate experimental measurements of the necking evolution, specifically its growth rate as a function of the diameter. The experiments show that increasing the specimen cross-section slows down the neck development. This behavior has been further investigated using two different kinds of numerical calculations: (1) axisymmetric finite element simulations and (2) one-dimensional finite difference computations. While the finite difference model only considers the normal stress along the longitudinal direction of the bar, the finite element model does not entail any simplification on the stress state of the specimen during the loading process. In agreement with the experiments, the finite element calculations show a decrease of the necking growth rate with the increase in the cross-section of the sample. On the contrary, the damping effect of the specimen cross-section on the necking evolution is not captured by the finite difference computations. We postulate that this result comes from the one-dimensional nature of the finite difference model. This work uncovers, by means of combined experiments and modelling, the key role played by stress multiaxiality in the growth rate of dynamic necks.

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“…They found that inertia has a strong stabilizing effect on the void growth process, and effects of strain hardening and thermal softening are relatively small. Through their theoretical study of dynamic tensile tests, Regazzoni and co-workers 37 showed that in all cases, inertia enhances ductility of materials. The works of many investigators 14,38,39 showed the same results.…”

Section: B Previous Workmentioning

confidence: 99%

“…This result was also given by Regazzoni and co-workers's work. 37 They numerically investigated dynamic tensile tests (⑀ Ͼ10 3 s Ϫ1 ) using a finite-difference method and found that at a strain rate exceeding 10 3 s Ϫ1 , inertia and strain-rate sensitivity lead to the effect of the same order of magnitude. The above information indicates that in the case of strain rates being in the range of 10 3 -10 7 s Ϫ1 , the rates of deformation (Ė d ) and kinetic (Ė k ) energies have the same order of magnitude.…”

Section: ͑75͒mentioning

confidence: 99%

Void-containing nonlinear materials subject to high-rate loading

Wang

1997

Journal of Applied Physics

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A new concept of dynamic potential ͑macrostress potential or macrostrain-rate potential͒, which has two components, i.e., deformation and kinetic potentials for heterogeneous materials under intense dynamic loading, is proposed using a micromechanical approach. In particular, for voided nonlinear materials, the approximate expression of the macrostress potential is derived through an upper bound approach. Simplified physical models for ductile porous materials ͑aggregates of voids and ductile matrix͒ are employed with the matrix material taken as power-law thermal viscoplastic and incompressible. Approximate velocity fields for the matrix are adopted to derive the dynamic loading criterion and an approximate functional form of the dynamic loading criterion is developed. The inertial, rate sensitivity, and thermal effects are directly included in the expressions of the macrostress potential and the dynamic loading function. Various features of the loading function are numerically investigated in detail. Numerical analysis reveals that both the dynamic growth of voids and the loading surface have strong rate dependence and temperature dependence. Experimental data, theoretical analysis, and numerical modeling indicate that the inertial and thermal effects play a very important role in the dynamic behavior of the voided nonlinear materials.

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Theoretical Study of the Dynamic Tensile Test

Cited by 58 publications

References 0 publications

Material aspects of dynamic neck retardation

Material aspects of dynamic neck retardation

Necking evolution in dynamically stretched bars: New experimental and computational insights

Void-containing nonlinear materials subject to high-rate loading

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