1,744 research outputs found
Transforming the U.S. Armed Forces
The U.S. armed forces themselves have embraced—at least rhetorically—the need to transform so as to meet the demands of information-age warfare. Nevertheless, in each service, efforts at trans- formation have faced opposition from traditionalists who perceive threats in new ways of war
Avoiding Trivia: The Role of Strategic Planning in American Foreign Policy
Students of American national security policy, particularly those without the benefit of firsthand policy-making experience, frequently under- or over- estimate the difficulty of formulating and implementing strategy in the U.S. government. As a result, observers tend either to portray senior policy makers as dolts or incompetents or to engage in a sort of strategic nihilism holding that it is impossible to develop sound strategy in this day and age
Mesoscopic modeling of the rtm process for homogenization
Intrinsic hybrids can be manufactured in a modified resin transfer molding (RTM) process
for fibre reinforced polymers. Our work concentrates on mesoscopic modeling for
temperature-dependent visco-elastic effects accompanied by curing within the RTM process.
During hybridization and later thermal loading the periodic mesostructure defined
by resin and fibres is taken into account as a representative volume element (RVE) subjected
to thermo-mechanical loading. Homogenization leads to results on the less resolved
macroscale. In the examples we illustrate the characteristic behavior of the mesoscopic
model, such as shrinking due to curing and temperature dependence and simulate the
RTM process as well as thermal loading of the cured composite with the finite-element-method
A coupled multiphase-field and carbon diffusion model for lower bainitic transformation
A multiphase-field method coupled to a Cahn-Hilliard diffusion model is pre-
sented in this paper. The underlying thermodynamic framework is based on the concept of
generalized stresses. A prototype model is developed to simulate the lower bainitic
transformation, including phase transitions, the separation of carbon within the supersat- urated
phase and the precipitation of carbides. The system of partial differential equa- tions
is solved with the finite element method. Numerical results of the model showing
the qualitative mechanism are discussed
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