Scalable File Systems for High Performance Computing Final Report

Simulations of mode I interlaminar fracture toughness tests of a carbon-reinforced composite material (BMS 8-212) were conducted with LSDYNA. The fracture toughness tests were performed by U.C. Berkeley. The simulations were performed to investigate the validity and practicality of employing decohesive elements to represent interlaminar bond failures that are prevalent in carbon-fiber composite structure penetration events. The simulations employed a decohesive element formulation that was verified on a simple two element model before being employed to perform the full model simulations. Care was required during the simulations to ensure that the explicit time integration of LSDYNA duplicate the near steady-state testing conditions. In general, this study validated the use of employing decohesive elements to represent the interlaminar bond failures seen in carbon-fiber composite structures, but the practicality of employing the elements to represent the bond failures seen in carbon-fiber composite structures during penetration events was not established

Dynamic access control in a concurrent object calculus

Abstract. We develop a variant of Gordon and Hankin’s concurrent object calculus with support for flexible access control on methods. We investigate safe administration and access of shared resources in the resulting language. Specifically, we show a static type system that guarantees safe manipulation of objects with respect to dynamic specifications, where such specifications are enforced via access changes on the underlying methods at runtime. By labeling types with secrecy groups, we show that well-typed systems preserve their secrets amidst dynamic access control and untrusted environments.