LLNL's program on multiscale modeling of polycrystal plasticity
At LLNL a multiscale modeling program based on information-passing has been established for modeling the strength properties of a body-centered-cubic metal (tantalum) ,. under conditions of extreme plastic deformation. The plastic deformation experienced by an explosively-formed shaped-charge jet is an example of "extreme deformation". The shaped charge liner material undergoes high strain rate deformation at high hydrostatic pressure. The constitutive model for flow stress, which describes the deformation, is highly dependent on pressure, temperature, and strain-rate. Current material models can not be extrapolated to these extreme conditions because the underlying mechanisms of plastic deformation are poorly reflected in the models and laboratory experiments are limited to pressures orders of magnitude less than actual pressures. This disparity between actual deformation conditions and those that can be attained in laboratory experiments is the principle motivation behind the multiscale modeling program. The fundamental elements of LLNL's multiscale modeling program are distinct models at the atomistic, microscale and mesoscale/continuum length scales. The information that needs to be passed from the lower to higher length scales has been carefully defined to bound the levels of effort required to ''bridge'' length scales. Information that needs to be generated by the different simulations has been specified by a multidisciplinary steering group comprised of physicists, materials scientists and engineers. The ultimate goal of the program is to provide critical information on strength properties to be used in continuum computer code simulations. The technical work-plan involves three principle areas which are highly coupled: 1) simulation development, 2) deformation experiments and 3) characterizations of deformed crystals. The three work areas are presented which provide examples of the progress of LLNL's program.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE Office of Defense Programs (DP)
- DOE Contract Number:
- W-7405-Eng-48
- OSTI ID:
- 3394
- Report Number(s):
- UCRL-JC-131096; DP0102052; ON: DE00003394
- Resource Relation:
- Conference: 7th International Symposium on Plasticity, Cancun, Mexcio, January 5-13, 1999
- Country of Publication:
- United States
- Language:
- English
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