Verification of experimental dynamic strength methods with atomistic ramp-release simulations
| Autor: | Alexander P. Moore, J. Matthew D. Lane, Justin Brown, Hojun Lim |
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| Rok vydání: | 2018 |
| Předmět: |
Bulk modulus
Materials science Physics and Astronomy (miscellaneous) Cauchy stress tensor Attenuation 02 engineering and technology Mechanics Strain rate 021001 nanoscience & nanotechnology 01 natural sciences Strength of materials Shear (sheet metal) Shear modulus 0103 physical sciences General Materials Science 010306 general physics 0210 nano-technology Lagrangian analysis |
| Zdroj: | Physical Review Materials. 2 |
| ISSN: | 2475-9953 |
| DOI: | 10.1103/physrevmaterials.2.053601 |
| Popis: | Material strength and moduli can be determined from dynamic high-pressure ramp-release experiments using an indirect method of Lagrangian wave profile analysis of surface velocities. This method, termed self-consistent Lagrangian analysis (SCLA), has been difficult to calibrate and corroborate with other experimental methods. Using nonequilibrium molecular dynamics, we validate the SCLA technique by demonstrating that it accurately predicts the same bulk modulus, shear modulus, and strength as those calculated from the full stress tensor data, especially where strain rate induced relaxation effects and wave attenuation are small. We show here that introducing a hold in the loading profile at peak pressure gives improved accuracy in the shear moduli and relaxation-adjusted strength by reducing the effect of wave attenuation. When rate-dependent effects coupled with wave attenuation are large, we find that Lagrangian analysis overpredicts the maximum unload wavespeed, leading to increased error in the measured dynamic shear modulus. These simulations provide insight into the definition of dynamic strength, as well as a plausible explanation for experimental disagreement in reported dynamic strength values. |
| Databáze: | OpenAIRE |
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