High Pressure Shock Compression Of Solids V

This book presents a set of basic understandings of the behavior and response of solids to propagating shock waves. The propagation of shock waves in a solid body is accompanied by large compressions, decompression, and shear. Thus, the shear strength of solids and any inelastic response due to shock wave propagation is of the utmost importance. Furthermore, shock compres sion of solids is always accompanied by heating, and the rise of local tempera ture which may be due to both compression and dissipation. For many solids, under a certain range of impact pressures, a two-wave structure arises such that the first wave, called the elastic prescursor, travels with the speed of sound; and the second wave, called a plastic shock wave, travels at a slower speed. Shock-wave loading of solids is normally accomplished by either projectile impact, such as produced by guns or by explosives. The shock heating and compression of solids covers a wide range of temperatures and densities. For example, the temperature may be as high as a few electron volts (1 eV = 11,500 K) for very strong shocks and the densification may be as high as four times the normal density.

This volume is concerned primarily with the chemical and physical effects of shock waves on typical materials. It compares naturally occurring materials with similar materials produced by shock compression in the laboratory, providing clues about the environment and events that produced the natural materials.

Presenting some of the most recent results of Russian research into shock compression, as well as historical overviews of the Russian research programs into shock compression, this volume will provide Western researchers with many novel ideas and points of view. The chapters in this volume are written by leading Russian specialists various fields of high-pressure physics and form accounts of the main researches on the behavior of matter under shock-wave interaction. The experimental portions contain results of studies of shock compression of metals to high and ultra-high pressure, shock initiation of polymorphic transformations, strength, fracture and fragmentation under shock compression, and detonation of condensed explosives. There are also chapters on theoretical investigations of shock-wave compression and plasma states in regimes of high-pressure and high- temperature. The topics of the book are of interest to scientists and engineers concerned with questions of material behavior under impulsive loading and to the equation of state of matter. Application is to questions of high-speed impact, inner composition of planets, verification of model representations of material behavior under extreme 1oading conditions, syntheses of new materials, development of new technologies for material processing, etc. Russian research differs from much of the Western work in that it has traditionally been wider-ranging and more directed to extremes of response than to precise characterization of specific materials and effects. Western scientists could expect to benefit from the perspective gained from close knowledge of the Russian work.

Since the 1950s shock compression research contributed greatly to scientific knowledge and industrial technology. As a result, for example, our understanding of meteorite impacts has substantially improved, and shock processes have become standard industrial methods in materials synthesis and processing. Investigations of shock-compressed matter involve physics,electrical engineering, solid mechanics, metallurgy, geophysics and materials science. The description of shock-compressed matter presented here, which is derived from physical and chemical observations, differs significantly from the classical descriptions derived from strictly mechanical characteristics. This volume, with over 900 references, provides an introduction for scientists and engineers interested in the present state of shock compression science.

This volume concerns the fracture and fragmentation of solid materials that occurs when they are subjected to extremes of stress applied at the highest possible rates. The plan for the volume is to address experimental, theoretical, and com putational aspects of high-rate dynamic fracture and fragmentation, with emphasis on recent work. We begin with several chapters in which the emphasis falls on experimental methods and observations. These chapters address both macroscopic responses and the microscopic cause of these re sponses. This is followed by several chapters emphasizing modeling-the physical explanation and mathematical representation of the observations. Some of the models are deterministic, while others focus on the stochastic aspects of the observations. Often, the ov\!rall objective of investigation of dynamic fracture and fragmentation phenomena is provision of a means for predicting the entire course of an event that begins with a stimulus such as an impact and proceeds through a complicated deformation and fracture pro cess that results in disintegration of the body and formation of a rapidly expanding cloud of debris fragments. Analysis of this event usually involves development of a continuum theory and computer code that captures the experimental observations by incorporating models of the important pheno mena into a comprehensive description of the deformation and fracture pro cess. It is to this task that the work of the last few chapters is devoted.

Developments in experimental methods are providing an increasingly detailed understanding of shock compression phenomena on the bulk, intermediate, and molecular scales. This third volume in a series of reviews of the curent state of knowledge covers several diverse areas. The first group of chapters addresses fundamental physical and chemical aspects of the response of condensed matter to shock comression: equations of state, molecular-dynamic analysis, deformation of materials, spectroscopic methods. Two further chapters focus on a particular group of materials: ceramics. Another chapter discusses shock-induced reaction of condensed-phase explosives. And a final pair of chapters considers shock phenomena at low stresses from the point of view of continuum mechanics.