High-rate strength response of tantalum from dynamic hole closure experiments

Nelms, Matthew; Lind, Jonathan; Margraf, Jonathan; Qamar, Sayyad Basim; Herrington, Joshua; Robinson, Andrew; Kumar, Mukul; Barton, Nathan R.

doi:10.1063/5.0107391

Cited by 8 publications

(1 citation statement)

References 47 publications

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“…Additional work is in progress to use this foundation to build a more extensive multi-phase model. First, the β-phase strength is being probed in more extreme conditions using Richtmyer-Meshkov instability (RMI) experiments for extreme strain rates, 69 hole closure experiments 70 for higher strains at high rates, and pulsed-power ramp-release experiments 3 for higher pressures. RMI experiments are also probing high-rate strength up into the γ-phase.…”

Section: Discussionmentioning

confidence: 99%

Calibration and validation of the foundation for a multiphase strength model for tin

Nguyen,

Burakovsky,

Fensin

et al. 2024

Journal of Applied Physics

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In this work, the Common Model of Multi-phase Strength and Equation of State (CMMP) model was applied to tin. Specifically, calibrations of the strength-specific elements of the CMMP foundation were developed with a combination of experiments and theory, and then the model was validated experimentally. The first element of the foundation is a multi-phase analytic treatment of the melt temperature and the shear modulus for the solid phases. These models were parameterized for each phase based on ab initio calculations using the software VASP (Vienna Ab initio Simulations Package) based on density functional theory. The shear modulus model for the ambient β phase was validated with ultrasonic sound speed measurements as a function of pressure and temperature. The second element of the foundation is a viscoplastic strength model for the β phase, upon which strength for inaccessible higher-pressure phases can be scaled as necessary. The stress–strain response of tin was measured at strain rates of 10−3 to 3×103s−1 and temperatures ranging from 87 to 373 K. The Preston–Tonks–Wallace (PTW) strength model was fit to that data using Bayesian model calibration. For validation, six forward and two reverse Taylor impact experiments were performed at different velocities to measure large plastic deformation of tin at strain rates up to 105s−1. The PTW model accurately predicted the deformed shapes of the cylinders, with modest discrepancies attributed to the inability of PTW to capture the effects of twinning and dynamic recrystallization. Some material in the simulations of higher velocity Taylor cylinders reached the melting temperature, thus testing the multiphase model because of the presence of a second phase, the liquid. In simulations using a traditional modeling approach, the abrupt reduction of strength upon melt resulted in poor predictions of the deformed shape and non-physical temperatures. With CMMP, the most deformed material points evolved gradually to a mixed solid–liquid but never a fully liquid state, never fully lost strength, stayed at the melt temperature as the latent heat of fusion was absorbed, and predicted the deformed shape well.

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Section: Discussionmentioning

confidence: 99%

Calibration and validation of the foundation for a multiphase strength model for tin

Nguyen,

Burakovsky,

Fensin

et al. 2024

Journal of Applied Physics

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Physical Regime Sensitivity

Prime

Merson

Chen

2023

J. dynamic behavior mater.

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This work presents a novel sensitivity approach that quantifies sensitivity to regimes of a model’s state variables rather than constitutive model parameters. This Physical Regime Sensitivity (PRS) determines which regimes of a model’s independent variables have the biggest influence on an experiment or application. PRS analysis is demonstrated on a strength model used in the simulation of a copper Taylor cylinder. In a series of simulations, the strength model was perturbed sequentially in local regimes of plastic strain, plastic strain rate, temperature and pressure, and then the prediction of cylinder shape was compared to unperturbed calculations. Results show, for example, that the deformed length of the cylinder was most sensitive to strength at a strain rate of 1.0 × 104/sec., but the deformed footprint radius was most sensitive to strength at a strain rate of about 4.0 × 104/sec. Compared to current histogram approaches, PRS can be used to design or interpret integrated experiments by identifying not just which regimes are accessed somewhere in the experiment but the causality question of which regimes actually affect the measured data. PRS should allow one to focus experimental and modeling efforts where they are most needed and to better interpret experiments.

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Shear localization as a damage mechanism in pore collapse under shock compression

Lovinger,

Kositski

2024

International Journal of Impact Engineering

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High-rate strength response of tantalum from dynamic hole closure experiments

Cited by 8 publications

References 47 publications

Calibration and validation of the foundation for a multiphase strength model for tin

Calibration and validation of the foundation for a multiphase strength model for tin

Physical Regime Sensitivity

Shear localization as a damage mechanism in pore collapse under shock compression

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