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Continuum Modeling and Simulation
Daniel Orlikowski, Christine J. Wu
Methods: Arbitrary Lagrange/Eulerian codes (ALE3D)
In many everyday applications, continuum simulations are essential to novel product development and fabrication. More importantly to us, it is essential to experimental design and interpretation. However, the fundamental quantities and constitutive models that compose thes simulations need to be either completely developed or improved. To this end, we are incorporating calculated smaller-length scale quantities (e.q. yield stress, chemical reaction pathways, etc.) to either guide experimental design work to probe new high pressure regimes or to continuously refine those constitutive models. Therefore, as an immediate tool to give crucial insight to the EMT group, continuum simulations using arbitrary Lagrange/Eulerian codes are used to evaluate sensitivity and impact of these fundamental quantities at the continuum length scale.
Current research:
- To examine the behavior of energetic materials under the stimulus of non-shock scenarios, such as low velocity impacts, friction and cutting motions during machining of high explosives (HEs), we employ continuum mechanics simulations for sensitivity tests of the constitutive models.
- Constitutive strength models, that combine calculations from several length scales from robust first principles combined with quantum based atomistic for a complete thermoelastic description, a Green's function simulation for the onset dislocation flow, and dislocation dynamics simulations for work hardening, are being evaluated and validated in comparison with experiments using standard hydrodynamic codes.
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Hydrodynamic simulations of novel
gas-gun compression wave experiments using functionally graded
material (FGM) impactors are being performed to compare and to
understand the high pressure material response.
- Another aspect of study within the general context of high strain-rate, compression waves is the wave propagation in materials---currently investigating dissipative and dispersive effects with intent to relatively quantify that in high pressure dynamic experiments
- Christine J. Wu, Tom Piggot, Jack Yoh and Jack Reaugh, "Numerical Modeling of Impact Initiation of High Explosive", LLNL Report, May 2006, UCRL-TR-221760.
- D. Orlikowski, P. Söderlind and J. A. Moriarty, " First-principles thermoelasticity of transition metals at high pressure: Tantalum prototype in the quasiharmonic limit," Phys. Rev. B 74, 054109 (2006).
- P. Söderlind and J. A. Moriarty, " First-principles theory of Ta up to 10 Mbar pressure: Structural and mechanical properties," Phys. Rev. B 57, 10340 (1998).
- J. H. Nguyen, D. Orlikowski, F. H. Streitz, J. A. Moriarty, and N. C. Holmes " High-pressure tailored compression: Controlled thermodynamic paths," J. Appl. Physics 100, 023508 (2006).
Metals & Alloys | Condensed Matter Physics | Physics & Adv. Tech. | LLNL
Maintained by Robert E. Rudd -- Last updated on 1 March 2007.
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