A5015824848- High-Velocity Impact and Material Behavior
- Energetic Materials and Combustion
- Microstructure and mechanical properties
- High-pressure geophysics and materials
- Composite Material Mechanics
- Crystallography and molecular interactions
- Metal and Thin Film Mechanics
- Rock Mechanics and Modeling
- Elasticity and Material Modeling
- Laser-Plasma Interactions and Diagnostics
- Numerical methods in engineering
- Metal Forming Simulation Techniques
- Structural Health Monitoring Techniques
- Fluid Dynamics Simulations and Interactions
- Advanced Mathematical Modeling in Engineering
- Boron and Carbon Nanomaterials Research
- Nuclear Materials and Properties
- Mechanical Behavior of Composites
- Metallurgy and Material Forming
- Vibration and Dynamic Analysis
- Probabilistic and Robust Engineering Design
- Microstructure and Mechanical Properties of Steels
- Nonlocal and gradient elasticity in micro/nano structures
- Ion-surface interactions and analysis
- Hydraulic and Pneumatic Systems
Los Alamos National Laboratory
2015-2024
Computational Physics (United States)
2024
Government of the United States of America
2023
Los Alamos Medical Center
2020
Deutsche Telekom (Austria)
2012
Georgia Institute of Technology
2009-2010
By combining experiments and modeling from three US national laboratories, we explore compressive strength in a well-characterized material, tantalum, across pressures zero to over 350 GPa, strain-rates 10−3/s 108/s temperatures 148 K 3800 K. Strength values 40+ are shown vary by nearly two orders of magnitude, 0.15 GPa 10 GPa. Cross-comparison these results allows pressure strain-rate dependencies be isolated, increases more significantly with than strain rate the range studied. Simulations...
Palladium is one of the most important technological materials, yet its phase diagram remains poorly understood. At ambient conditions, solid face-centered cubic (fcc). However, another Pd, body-centered (bcc), was very recently predicted in two independent theoretical studies to occur at high pressures and temperatures. In this work, we report an experimental study on room-temperature equation state (EOS) Pd a pressure 80 GPa, as well including both fcc-Pd bcc-Pd. Our approach consists ab...
Predictive modeling of materials requires accurately parameterized constitutive models. Parameterizing models that describe dynamic strength and plasticity require experimentally probing in a variety strain rate regimes. Some experimental protocols (e.g., plate impact) probe the response material using indirect measures such as free surface velocimetry. Manual efforts to parameterize often lead non-unique optimizations without quantification parameter uncertainty. This study uses Bayesian...
The microstructure of plastic bonded explosives (PBXs) is known to influence behavior during mechanical deformation, but characterizing the can be challenging. For example, explosive crystals and binder in formulations such as PBX 9501 do not have sufficient X-ray contrast obtain three-dimensional data by situ, absorption imaging. To address this difficulty, we formulated a series PBXs using octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) low-density systems. binders were...
A continuum model for the high-rate, thermo-mechanical deformation of single-crystal cyclotrimethylene trinitramine (RDX) is developed. The includes effects anisotropy, large deformations, nonlinear thermo-elasticity, phase transformations, and plastic slip. multiplicative decomposition gradient used. volumetric elastic component accounted through a free-energy based equation state low- (α) high-pressure (γ) polymorphs RDX. Crystal plasticity addressed using phenomenological thermal...
Equations of state for the α and γ polymorphs energetic molecular crystal cyclotrimethylene trinitramine (RDX) have been developed from their Helmholtz free energies. The ion motion contribution to energy is represented by Debye models with density-dependent temperatures that are parameterized vibrational densities states computed dispersion-corrected density functional theory. By separating into low frequency modes mainly lattice phonon character high intramolecular we were able...