Journal article
Johnson–Cook yield functions for cyclotetramethylene-tetranitramine (HMX) and cyclotrimethylene-trinitramine (RDX) derived from single crystal plasticity models
Journal of applied physics, Vol.135(14), 145901
04/14/2024
DOI: 10.1063/5.0188263
Abstract
High-fidelity constitutive models are critical for accurate meso-scale continuum modeling and prediction of shock initiation of crystalline energetic materials (EMs). While empirically calibrated or atomistic-guided anisotropic elastoplastic models of EM such as cyclotetramethylene-tetranitramine (HMX) and cyclotrimethylene-trinitramine (RDX) capture important micromechanical phenomena (such as dislocation evolution, slip-resistance, and anisotropic elasticity), the computational cost of using anisotropic single-crystal plasticity models can become prohibitive for meso-scale computations of void-collapse and hotspot formation in microstructures. Thermo-mechanically representative, isotropic, pressure, temperature, and rate-dependent material constitutive models are practical alternatives for meso-scale simulations of the shock response of microstructures. To this end, this work constructs physically consistent isotropic plasticity from anisotropic single-crystal plasticity models for HMX and RDX. State-of-the-art crystal plasticity models for HMX and RDX are used to compute the stress states in single crystals oriented in three different directions relative to shocks generated by impact at velocities ranging from 100 to 1000 m/s. Post-shock von Mises stress fields for the three orientations are then used to calibrate the strain-rate hardening coefficient and the reference strain rate for a rate-dependent Johnson–Cook (JC) yield surface model. We compare the pressures and the post-shock von Mises stresses between the JC and the anisotropic models to show that the isotropic computations closely approximate the averaged deformation response of the three different crystal orientations. We then model the interaction of a shock generated by a 500 m/s impact with a 0.5 μm void and show that the pressures and the deviatoric stresses obtained using the isotropic model closely match those computed from anisotropic models for both HMX and RDX. The resulting isotropic J2 plastic flow model for HMX and RDX can be employed to perform meso-scale simulations for energy localization due to shear bands and void collapse in the two materials.
Details
- Title: Subtitle
- Johnson–Cook yield functions for cyclotetramethylene-tetranitramine (HMX) and cyclotrimethylene-trinitramine (RDX) derived from single crystal plasticity models
- Creators
- Oishik Sen - SRI InternationalPradeep K. Seshadri - University of IowaNirmal Kumar Rai - University of IowaJames Larentzos - United States Army Combat Capabilities Development CommandJohn Brennan - United States Army Combat Capabilities Development CommandTommy Sewell - University of MissouriCatalin R. Picu - Rensselaer Polytechnic InstituteH. S. Udaykumar - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Journal of applied physics, Vol.135(14), 145901
- DOI
- 10.1063/5.0188263
- ISSN
- 0021-8979
- eISSN
- 1089-7550
- Number of pages
- 23
- Grant note
- FA9550-19-1-0318 / Air Force Office of Scientific Research (10.13039/100000181) W911NF-19-2-0110 / DEVCOM Army Research Laboratory (10.13039/100019923)
- Date published
- 04/14/2024
- Academic Unit
- IIHR--Hydroscience and Engineering; Injury Prevention Research Center; Mechanical Engineering
- Record Identifier
- 9984584906702771
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