Showing papers by "Steven J. Plimpton published in 2004"
TL;DR: In this article, a semi-implicit time-advance approach was used to simulate the growth rate of resistive tearing modes in 3D nonlinear non-ideal magnetohydrodynamics.
517 citations
TL;DR: In this paper, a double-bridging algorithm was used to generate new configurations of tethered chains that are substantially different than the original two chains such that the systems can be equilibrated in a reasonable amount of cpu time.
Abstract: The adhesion between a glassy polymer melt and substrate is studied in the presence of end-grafted chains chemically attached to the substrate surface. Extensive molecular dynamics simulations have been carried out to study the effect of the areal density ∑ of tethered chains and tensile pull velocity v on the adhesive failure mechanisms. The initial configurations are generated using a double-bridging algorithm in which new bonds are formed across a pair of monomers equidistant from their respective free ends. This generates new chain configurations that are substantially different than the original two chains such that the systems can be equilibrated in a reasonable amount of cpu time. At the slowest tensile pull velocity studied, a crossover from chain scission to crazing is observed as the coverage increases, while for very large pull velocity, only chain scission is observed. As the coverage increases, the sections of the tethered chains pulled out from the interface form the fibrils of a craze that are strong enough to suppress chain scission, resulting in cohesive rather than adhesive failure. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 199–208, 2004
80 citations
TL;DR: In this article, the transition from two-dimensional to three-dimensional granular packings is studied using large-scale discrete element computer simulations, focusing on vertical stress profiles and examine how they change with dimensionality.
60 citations
TL;DR: This paper describes a grid transfer algorithm suitable for massively parallel codes which use multiple grids that uses a rendezvous technique wherein a third decomposition is used to search for elements in one grid that contain nodal points of the other.
42 citations
01 Jun 2004
TL;DR: In this article, a level set based feature-scale model for low-pressure and plasma enhanced chemical vapor deposition (LPCVD, LPCVD and PECVD) is presented.
Abstract: The surface micromachining processes used to manufacture MEMS devices and integrated circuits transpire at such small length scales and are sufficiently complex that a theoretical analysis of them is particularly inviting. Under development at Sandia National Laboratories (SNL) is Chemically Induced Surface Evolution with Level Sets (ChISELS), a level-set based feature-scale modeler of such processes. The theoretical models used, a description of the software and some example results are presented here. The focus to date has been of low-pressure and plasma enhanced chemical vapor deposition (low-pressure chemical vapor deposition, LPCVD and PECVD) processes. Both are employed in SNLs SUMMiT V technology. Examples of step coverage of SiO{sub 2} into a trench by each of the LPCVD and PECVD process are presented.
10 citations