Simulations of mode I interlaminar fracture toughness tests of a carbon-reinforced composite material 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.

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Abs&ac&--FVfetal Evaporated (ME) tape comprises bundles of inclined columns each of which consists of small crystdine grains. To simulate the magnetic behaviour of ME tape we have developed a model, using a Monte Carlo algorithm, to represent a single column of spherical grains whose radii are generated from a log-normal distribution. The dynamic process of the magnetic moments is explored by utilizing the Landau-Lifschitz equations. We demonstrate that the microstructure of the column and direction of the easy axes influence the magnetic reversal process. By varying the strength of the exchange coupling parameter its effect on the amount of co-operative switching is reported. The results suggest that high exchange coupling acts to keep moments aligned, resulting in higher values of coercivity, The reversal mechanism is initiated at the ends of the column and then propagates through the column. 891 M. E. Schabes, "Micromagnetic theory of non-uniform magnetization prKesses in magnetic recording p~c l e s ,~~ J . M~~~. M~~~. M~~~~. , VOP. 92, pp. 68-74, 1990. 0 0 Fig. 4. Coercive state for aligned easy axes, for C*-0.04, within a single C O l U r n . 95, pp. 249-288,1991.