[en] The HDZP II is an experiment with the objective of taking a z-pinch plasma, created from a small diameter solid deuterium fiber, up to the Pease-Braginskii current limit while maintaining Bennett equilibrium (constant radius) throughout the current pulse. This paper discusses this experiment

[en] When calculating the impact-force of an aircraft striking a building the deformation of this building is not taken in account. To which extent the elastic displacements of a structure influence the impact on plates and on spherical shells is to be investigated. The aircraft is idealized by a linear mass-spring-dashpot-combination, which can suffer elastic as well as plastic deformation. This 'aircraft' normally strikes a spherical shell at the apex. The time-dependent reactions of the shell as a function of the unknown impact load F(t) are expanded in terms of the normal modes. The continuity condition at the impact point leads to an integral-equation for F(t), solved by Laplace transformation. F(t) is computed for hemispheres with several ratios of thickness to radius, edge conditions and aircraft-parameters. In all cases F(t) differs very little from the function obtained when the aircraft strikes a rigid wall. The calculation of the normal displacements w(t) at various points of the shell shows that the influence of the impact is bounded on a small region upon the impact point. Therefore, boundary conditions can not be of interest. When considering the function w(t) a vibration of large amplitude and of low frequency appears with a superposed oscillation of small amplitudes and higher frequency. The fundamental frequency agrees very well with that of the idealized aircraft, while the higher frequency belongs to a natural frequency of the hemispherical shell; not the fundamental natural frequency of the shell becomes visible but a higher one. When calculating the function w(t) the different modes of vibration have different influence, it is not the fundamental mode but a higher one that is decisive. If the 'aircraft' strikes a thin plate of similar parameters, the impact load is much more influenced by the elastic deformation of the plate. Contrary to the hemisphere in this case only the two lowest eigenmodes are of interest

[en] When calculating the impact-force of an aircraft striking a building the deformation of this building is not taken in account. To which extent the elastic displacements of a structure influence the impact on plates and on spherical shells is investigated in this paper. The aircraft is idealized by a linear mass-spring-dashpot-combination, which can suffer elastic as well as plastic deformation. This 'aircraft' normally strikes a spherical shell at the apex. The time-dependent reactions of the shell as a function of the unknown impact load (F)t are expanded in terms of the normal modes, which are Legendre functions. The continuity condition at the impact point leads to an integral-equation for F(t), which may be solved by Laplace transformation. (Auth.)

[en] The operation and plasma diagnostics for the High Density Z-Pinch II experiment are discussed. The testing and future experiments of the HDZP II experiment are also discussed

[en] The Plasma Theory and Simulation Group (PTSG) is collaborating with LLNL in order to model the edge region of a tokamak plasma and its interaction with the diverter plate. In the overall framework of the project, MHD will be used to model the bulk plasma. Near the edge, the MHD model will interface with the gyrokinetic code UEDGE developed at LLNL. Since the UEDGE model approximations may not be accurate within a few cyclotron radii of the diverter plate, the UEDGE code will interface with a collisional PIC-hybrid code developed by the PTSG under this project. The PTSG PIC code will include a self-consistent potential with kinetic or fixed hydrogen ions. The sputtering profile of the plate, under development at LLNL, will be used as input to the PIC code in order to correctly model the kinetic behavior of sputtered carbon. These carbon products will interact with hydrogen according to known chemistry cross-sections. While some kinetic electrons may be used to model the fast tail of the distribution function (if necessary), the bulk of the electron population will be modeled as being in thermal equilibrium using the Boltzmann relation, resulting in a significant improvement in code speed. Coulomb collisions may also be considered. The Boltzmann model has been implemented with various features in three of the PTSG codes: XPDP1 and OOPD1 (both 1d-3v), and OOPIC (2d-3v), according to the methodology of Cartwright [1]. When the model is fully implemented, it will include fluid interaction with the boundaries, energy conservation through the temperature term, and take into account collisions with the Boltzmann species. A more rigorous convergence analysis has been developed than is outlined in [1]; boundary effects are included explicitly in a formulation valid in arbitrary coordinate systems. In OOPD1, the Boltzmann model is included in an object-oriented manner as part of a general fluid model framework. The basic Boltzmann solver has been implemented and shown to give self-consistent results. The details and results were described in detail in a talk presented at LLNL (updated slides attached). Currently, the output of the three codes is being compared for a test case of a current-driven DC discharge. Computational speed-up and accuracy will be compared between PIC and the Boltzmann-PIC hybrid. A framework for general binary and three-body collisions is being developed for OOPD1. Given known cross-sections or reaction rates, this will function as a chemistry model for the code. The framework may then be imported into OOPIC

No abstract available

[en] Dynamical loaded structures can be analysed by spectral representations, which usually lead to an enormous computational effort. If it is possible to find a fitting dynamical load factor, the dynamical problem can be reduced to a statical one. The computation of this statical problem is much more simpler. The disadvantage is that the dynamical load factor usually leads to a very rough approximation. In this paper it will be shown, that by combination of these two methods, the approximation of the dynamical load factor can be improved and the consumption of computation time can be enor

[en] For nuclear power plants located in the immediate vicinity of cities and airports safeguarding against an accidental aircraft strike is important. Because of the complexity of such an aircraft crash the building is ordinarily designed for loading by an idealized dynamical load F(t), which follows from measurements (aircraft striking a rigid wall). The extent to which the elastic displacements of a structure influence the impact load F(t) is investigatd in this paper. The aircraft is idealized by a linear mass-spring-dashpot combination which can easily be treated in computations and which can suffer elastic as well as plastic deformations. This 'aircraft' normally strikes a spherical shell at the apex. The time-dependent reactions of the shell as a function of the unknown impact load F(t) are expanded in terms of the normal modes, which are Legendre functions. The continuity condition at the impact point leads to an integral equation for F(t) which may be solved by Laplace transformation. F(t) is computed for hemispheres with several ratios of thickness to radius, several edge conditions and several 'aircraft' parameters. In all cases F(t) differs very little from that function obtained for the case of the aircraft striking a rigid wall. (Auth.)

[en] Because of the complexity of an aircraft crash the building is ordinarily loaded by an idealized dynamical load which follows from measurements (aircraft striking a rigid wall). The result of the presented calculations is that the dynamical load of impact of a deformable aircraft on an elastic shell is much more influenced by the aircraft model under consideration than by the elastic displacements of the shell. (HP)

[en] Dynamical loaded structures can be analysed by spectral representations, which usually lead to an enormous computational effort. If it is possible to find a fitting dynamical load factor, the dynamical problem can be reduced to a statical one. The computation of this statical problem is much simpler. The disadvantage is that the dynamical load factor usually leads to a very rough approximation. In this paper it will be shown, that by combination of these two methods, the approximation of the dynamical load factor can be improved and the consumption of computation time can be enormously reduced. (Auth.)