Nonlinear Deformation of Structure Elementsfrom Different Materials under Impulse and Shock Loads

simulation of high-rate deformation processes, three-dimensional models are used. The following determined relationships are taken into account: elastic-plastic deformation (according to the theory of dynamic plastic deformation); the dynamic properties of the materials, which change during deformation; the finite displacements and deformations. The problem is solved by the finite elements method. The paper analyzes the impact of pulse and shock loads performed on the elements of various constructions made of different materials. Comparison of the research results shows that the elements from the improved composite material possess both the required strength and lowest weight. Furthermore, the experimental and numerical results are compared as an example of the influence of the impulse load on the composite material plate with a cut. The paper shows the features of the distribution and localization of the stress intensity and displacements at the impulse and impact loading in the multi-layered structural elements. The deformation processes occur in different stages up to the elastic-plastic finite deformations depending on the speed of the projectile. The results of these studies were used in the analysis of the dynamic strength of real structural elements

Development of hollow electron beams for proton and ion collimation

Magnetically confined hollow electron beams for controlled halo removal in high-energy colliders such as the Tevatron or the LHC may extend traditional collimation systems beyond the intensity limits imposed by tolerable material damage. They may also improve collimation performance by suppressing loss spikes due to beam jitter and by increasing capture efficiency. A hollow electron gun was designed and built. Its performance and stability were measured at the Fermilab test stand. The gun will be installed in one of the existing Tevatron electron lenses for preliminary tests of the hollow-beam collimator concept, addressing critical issues such as alignment and instabilities of the overlapping proton and electron beams.Comment: 3 pp. 1st International Particle Accelerator Conference: IPAC'10, 23-28 May 2010: Kyoto, Japa

Hollow Electron Beam Collimator: R&D Status Report

Magnetically confined hollow electron beams for controlled halo removal in high-energy colliders such as the Tevatron or the LHC may extend traditional collimation systems beyond the intensity limits imposed by tolerable material damage. They may also improve collimation performance by suppressing loss spikes due to beam jitter and by increasing capture efficiency. A hollow electron gun was designed and built. Its performance and stability were measured at the Fermilab test stand. The gun will be installed in one of the existing Tevatron electron lenses for preliminary tests of the hollow-beam collimator concept, addressing critical issues such as alignment and instabilities of the overlapping proton and electron beams.Comment: 5 pp. 14th Advanced Accelerator Concepts Workshop 13-19 Jun 2010: Annapolis, Marylan

Numerical modeling of porous elastic-viscoplastic material with tensile failure

We report here on the development of a multi-material hydrocode for simulation of elastoplastic flows with large deformations. Using this hydrocode a new constitutive model for porous elastic-viscoplastic materials has been evaluated and the penetration of an aluminum projectile into porous rock material has been simulated numerically. The dependence of the penetration depth upon model parameters has been studed

Beam halo dynamics and control with hollow electron beams

Experimental measurements of beam halo diffusion dynamics with collimator scans are reviewed. The concept of halo control with a hollow electron beam collimator, its demonstration at the Tevatron, and its possible applications at the LHC are discussed.Comment: 5 pages, 4 figures, in Proceedings of the 52nd ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams (HB2012), Beijing, China, 17-21 September 201

SPECIFIC HEAT CAPACITY AND THERMAL CONDUCTIVITY OF HEAT STORAGE MATERIALS BASED ON PARAFFIN, BROWN-COAL WAX AND POLYETHYLENE WAX

The present paper overviews heat storage materials (HSM) with phase change based on organic compounds. They consist of paraffin, brown-coal wax and polyethylene wax. These materials are produced on an industrial scale for the foundry work. It is shown that heat capacity of HSM in the solid and liquid states can be used for heat storage in addition to the heat of phase change. The results of investigations of phase change during heating and cooling HSM are presented. The studies are carried out by differential scanning calorimetry (DSC). The measurement techniques of the specific heat capacity and the coefficient of thermal conductivity are shown. Temperature dependences of the specific heat capacity of HSM in the solid and liquid states are researched by DSC. Values of the coefficient of thermal conductivity are determined by contact stationary technique of the flat plate over the entire temperature range of the operation of heat storage system