Physical Regime Sensitivity

Prime, Michael B.; Merson, Jacob; Chen, S.-R.

doi:10.1007/s40870-023-00375-w

Cited by 3 publications

(1 citation statement)

References 59 publications

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“…The footprint diameter, on the other hand, is also sensitive to the shape of the stress-strain curve and the competition between strain hardening and thermal softening. 68 Thus, the diameter predictions are less accurate because the PTW fits in Fig. 14 smooth through the sigmoid caused by twinning and also do not perfectly capture the hardening at higher strains.…”

Section: Validation On Taylor Cylinder Impact Experimentsmentioning

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: Validation On Taylor Cylinder Impact Experimentsmentioning

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

Self Cite

View full text Add to dashboard Cite

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Robust implementation of Physical Regime Sensitivity and demonstration on Richtmyer–Meshkov Instability experiments

Dyer,

Waters,

Prime

2024

Journal of the Mechanics and Physics of Solids

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Multiscale Richtmyer-Meshkov instability experiments to isolate the strain rate dependence of strength

Prime,

Fensin,

Jones

et al. 2024

Phys. Rev. E

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Theoretical analysis of Richtmyer-Meshkov instability (RMI) experiments for solid strength shows that the strain rate for a given shock should be inversely proportional to the length scale of the sine wave perturbations when η0k, the nondimensional amplitude to wavelength ratio, is held fixed. To isolate the effect of strain rate on strength, free-surface RMI specimens of annealed copper were prepared with three perturbation regions with the same η0k but different length scales, characterized by the wavelength λ varying by a factor of 4.9 from 65 to 130 to 320µm. Three such targets with different fixed η0k′s were impacted to a shock pressure of 25 GPa, and the instability evolution was measured with photon Doppler velocimetry. Strengths estimated by comparing hydrocode simulation to the data increased from 700 to 1200 MPa as λ decreased. The different η0k targets exercised increasing amounts of plastic strain yet showed no evidence of strain hardening. Physical regime sensitivity analysis determined that for 320−65µm wavelength perturbations, the effective strain rates increased from 8.7×106 to 3.3×107s−1, a factor of 3.8. Thus, the predicted strain rate scaling was mostly achieved but slightly suppressed by increased strength at higher rates. The RMI strength estimates were plotted against constitutive testing data on copper from the literature to show striking evidence of the strength upturn at higher strain rates. Published by the American Physical Society 2024

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Physical Regime Sensitivity

Cited by 3 publications

References 59 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

Robust implementation of Physical Regime Sensitivity and demonstration on Richtmyer–Meshkov Instability experiments

Multiscale Richtmyer-Meshkov instability experiments to isolate the strain rate dependence of strength

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