Breannan Smith

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We consider the simulation of dense foams composed of microscopic bubbles, such as shaving cream and whipped cream. We represent foam not as a collection of discrete bubbles, but instead as a continuum. We employ the <i>material point method</i> (MPM) to discretize a hyperelastic constitutive relation augmented with the Herschel-Bulkley model of(More)
We develop a method for reliable simulation of elastica in complex contact scenarios. Our focus is on firmly establishing three parameter-independent guarantees: that simulations of well-posed problems (a) have no interpenetrations, (b) obey causality, momentum- and energy-conservation laws, and (c) complete in finite time. We achieve these guarantees(More)
Resolving simultaneous impacts is an open and significant problem in collision response modeling. Existing algorithms in this domain fail to fulfill at least one of five physical desiderata. To address this we present a simple generalized impact model motivated by both the successes and pitfalls of two popular approaches: pair-wise propagation and linear(More)
We develop an algorithm for the efficient and stable simulation of large-scale elastic rod assemblies. We observe that the time-integration step is severely restricted by a strong nonlinearity in the response of stretching modes to transversal impact, the degree of this nonlinearity varying greatly with the shape of the rod. Building on these observations,(More)
An optimal control system for the intra-aortic balloon pump (IABP) is presented. Control of the IABP is based on a performance index formulated to reflect a tradeoff between maximising cardiac oxygen supply and minimising cardiac oxygen consumption. In the performance index, mean diastolic pressure (MDP) was used to represent oxygen availability and peak(More)
An innovative computational tool (DAG-MCNP) has been developed for efficient and accurate 3-D nuclear analysis of geometrically complex fusion systems. Direct coupling with CAD models allows preserving the geometrical details, eliminating possible human error, and faster design iterations. DAG-MCNP has been applied to perform 3-D nuclear analysis for(More)
Iterative algorithms are frequently used to resolve simultaneous impacts between rigid bodies in physical simulations. However, these algorithms lack formal guarantees of termination, which is sometimes viewed as potentially dangerous, so failsafes are used in practical codes to prevent infinite loops. We show such steps are unnecessary. In particular, we(More)
Detailed 3-D neutronics calculations have been performed for the US DCLL TBM. The neutronics calculations were performed directly in the CAD model using the DAG-MCNP code that allows preserving the geometrical details. Detailed high-resolution, high-fidelity profiles of the nuclear parameters were generated using fine mesh tallies. These included tritium(More)
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