Abstracts

Foreign participants

A set of investigations is described that recently conducted at the Institute for Industrial Mathematics, Beer-Sheva, Israel concerning mathematical and engineering problems of high-speed penetration of protective structures manufactured of ductile, brittle and composite materials. A general, problem-oriented approach is applied to the analysis and examination of this field in the wide-range research. In the framework of the approach, advanced straightforward models are developed resulting in analytical and computer solutions. The following penetration problems are discussed:

1. Initial penetration. Metal plate of arbitrary thickness. An analytical model is developed of purely hydrodynamic formulation. The model enables the projectile velocity loss to be determined at the first, unsteady-state stage of the penetration.
2. Long projectiles vs metal slabs. An analytical dynamic thermo-plastic flow-jet model is introduced, based on conservation laws with regard to plastic flow resistance. An advancement is the representation of constrained flow of projectile and target materials. The model allows the sizes of the crater and the mushrooming head of the eroded projectile to be determined. The model is based on taking into account
   (a) the localization of the thermoplastic shear, initiation and propagation of the melting wave which results in separation of plastic jets of the projectile and target materials, and
   (b) the resistance to the plastic flow under the forward-to-back transition of the jets. Good agreement is achieved with experimental data.
   
3. Long projectiles vs a metal plate of moderate thickness. A two-stage analytical perforation model is developed. The first stage is described by the above model, while the other is based on a so-called "spherical plastic flow" model representation. Two parameters introduced into the second model are to be determined by the experiments suggested. The model enables the residual parameters of the projectile to be estimated.
4. Short projectiles vs a thin metal plate. An engineering model based on energy considerations is introduced for calculation of thin metal plate perforation by a small projectile. The model allows the ballistic limit and the residual velocity to be determined. It is well confirmed by independent experiments.
5. Composite armor. A combined analytical-numerical model is developed that allows penetration-perforation process in layered composite tiles metal- ceramic, metal-fabric, ceramic-fabric, etc.) to be calculated. The model is based on account taken of
   (a) the projectile shaping during the primary penetration stage,
   (b) fracture wave propagation and arrest in ceramics,
   (c) dynamic interaction of layers, and
   (d) delamination and fracture of the composite fabric backing.

Note. Abstracts are published in author's edition

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