Model of plastic deformation for extreme loading conditions

Preston, Dean L.; Tonks, D. L.; Wallace, Duane C.

doi:10.1063/1.1524706

Cited by 464 publications

(211 citation statements)

References 23 publications

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“…However, the MTS model is limited to strain-rates less than around 10 7 /s. The Preston-Tonks-Wallace (PTW) model (Preston et al (2003)) is also physically based and has a form similar to the MTS model. However, the PTW model has components that can model plastic deformation in the overdriven shock regime (strain-rates greater that 10 7 /s).…”

Section: Flow Stress Modelsmentioning

confidence: 99%

“…The Preston-Tonks-Wallace (PTW) model (Preston et al (2003)) attempts to provide a model for the flow stress for extreme strain-rates (up to 10 11 /s) and temperatures up to melt. A linear Voce hardening law is used in the model.…”

Section: Ptw Flow Stress Modelmentioning

confidence: 99%

“…These models are the Johnson-Cook model (Johnson and Cook (1983)), the Steinberg-Cochran-Guinan-Lund model (Steinberg et al (1980); Steinberg and Lund (1989)), the Zerilli-Armstrong model (Zerilli and Armstrong (1987)), the Mechanical Threshold Stress model (Follansbee and Kocks (1988)), and the Preston-Tonks-Wallace model (Preston et al (2003)). We also evaluate the associated shear modulus models of Varshni (1970), Steinberg et al (1980), and Nadal and Le Poac (2003).…”

Section: Introductionmentioning

confidence: 99%

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Effect of strain rate on microstructure of polycrystalline oxygen-free high conductivity copper severely deformed at liquid nitrogen temperature

Zhang

Shim

2010

Acta Materialia

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Phenomenological plastic flow stress models are used extensively in the simulation of large deformations of metals at high strain-rates and high temperatures. Several such models exist and it is difficult to determine the applicability of any single model to the particular problem at hand. Ideally, the models are based on the underlying (subgrid) physics and therefore do not need to be recalibrated for every regime of application. In this work we compare the Johnson-Cook, Steinberg-Cochran-Guinan-Lund, Zerilli-Armstrong, Mechanical Threshold Stress, and Preston-Tonks-Wallace plasticity models. We use OFHC copper as the comparison material because it is well characterized. First, we determine parameters for the specific heat model, the equation of state, shear modulus models, and melt temperature models. These models are evaluated and their range of applicability is identified. We then compare the flow stresses predicted by the five flow stress models with experimental data for annealed OFHC copper and quantify modeling errors. Next, Taylor impact tests are simulated, comparison metrics are identified, and the flow stress models are evaluated on the basis of these metrics. The material point method is used for these computations. We observe that the all the models are quite accurate at low temperatures and any of these models could be used in simulations. However, at high temperatures and under high-strain-rate conditions, their accuracy can vary significantly.

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Section: Flow Stress Modelsmentioning

confidence: 99%

Section: Ptw Flow Stress Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of strain rate on microstructure of polycrystalline oxygen-free high conductivity copper severely deformed at liquid nitrogen temperature

Zhang

Shim

2010

Acta Materialia

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“…The Steinberg-Guinan model does not have a peak in its stress-strain curve. Other strength models developed for high-rate deformation, such as the Hoge-Mukherjee [70], Steinberg-Lund [29], and PTW [32] models, also do not have stress peaks. The stress peak results from the system being driven at a rate higher than the plasticity can respond, an effect that is not included in these strength models.…”

Section: =ε Yy (T)=(-1/2) ε Zz (T) + O(ε Zz 2 ) Using Eq (2) the Stmentioning

confidence: 99%

High-Rate Plastic Deformation of Nanocrystalline Tantalum to Large Strains: Molecular Dynamics Simulation

Rudd

2009

MSF

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Recent advances in the ability to generate extremes of pressure and temperature in dynamic experiments and to probe the response of materials has motivated the need for special materials optimized for those conditions as well as a need for a much deeper understanding of the behavior of materials subjected to high pressure and/or temperature. Of particular importance is the understanding of rate effects at the extremely high rates encountered in those experiments, especially with the next generation of laser drives such as at the National Ignition Facility. Here we use large-scale molecular dynamics (MD) simulations of the high-rate deformation of nanocrystalline tantalum to investigate the processes associated with plastic deformation for strains up to 100%. We use initial atomic configurations that were produced through simulations of solidification in the work of Streitz et al [Phys. Rev. Lett. 96, (2006) 225701]. These 3D polycrystalline systems have typical grain sizes of 10-20 nm. We also study a rapidly quenched liquid (amorphous solid) tantalum. We apply a constant volume (isochoric), constant temperature (isothermal) shear deformation over a range of strain rates, and compute the resulting stress-strain curves to large strains for both uniaxial and biaxial compression. We study the rate dependence and identify plastic deformation mechanisms. The identification of the mechanisms is facilitated through a novel technique that computes the local grain orientation, returning it as a quaternion for each atom. This analysis technique is robust and fast, and has been used to compute the orientations on the fly during our parallel MD simulations on supercomputers. We find both dislocation and twinning processes are important, and they interact in the weak strain hardening in these extremely fine-grained microstructures.

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“…This slip system activation will be discussed in more depth in section 6.6.3. The work performed by Ravelo [68] according to the Preston-TonksWallace strength model [69] shows the flow shear stress of [001] loading direction is always higher than the others, because the higher activation energy is high with this loading direction due to the high interatomic potential caused by the high pressure. This is possibly another reason why the [001] sample has significant high HEL.…”

Section: Equation Of State Of Tamentioning

confidence: 99%