Physical and physicochemical processes that are described by the concept “explosion” are characterized by release of a large amount of energy in a confined space within short periods of time. Not going deeply into the description of the variety of such processes, which were considered in detail in widely known monographs, we would like to point out that many features of explosive processes still remain the subject of thorough studies. While initially the phenomenon of explosion was studied almost exclusively for subsequent military applications, nowadays the received knowledge has found wide technological application. For example, explosion for ejection is widely used during construction of canals and mining of pits. One of the most striking examples of a directional explosion for ejection is the constructing of an anti‐mudflow dam in the Medeo Valley (the Almaty Region, Kazakhstan) in 1968.

Out of many applications of explosion, the following examples may be particularly emphasized as most widely used in industry:

• Explosive forming – fabrication of tank bottoms, expansion of pipes, extrusion, punching and final calibration of pre‐prepared products.
• Explosive welding – cladding of materials for chemical industry, welding of pipes, fabrication of composite materials, welding of materials, which cannot be joined using common technologies of fusion welding (i.e. Ti‐Fe, Al‐Cu, Al‐Fe, etc.).
• Explosive cutting – separation of materials, parts, or constructions when common technologies of cutting are inapplicable. The typical examples are separation of rocket stages, dismantling of thick‐walled autoclaves at nuclear power plants, and disposing of ships, tanks, etc.
• Explosive hardening – hardening of railway frogs, excavator bucket teeth, parts of mining machines, internal surfaces of various mixers, mills, etc.
• Explosive compaction – fabrication of billets from powder and porous materials.
• Shock‐assisted synthesis of materials – fabrication of diamond from carbon, synthesis of cubic boron nitride, synthesis of novel metastable materials.
• Synthesis of rapidly quenched materials – fabrication of amorphous and micro‐ and nanocrystalline alloys with specific properties.
• Modification of properties of high temperature superconductors aiming to increase the superconducting transition temperature.

Among other applications of explosion, one may mention mining, perforation of oil wells, generation of mega‐gauss magnetic fields and mega‐ampere current pulses, acceleration of bodies to hypersound velocities, etc.

Military applications of explosion do also continue to develop and improve. In this field it is necessary to mention the improvement in the methods of explosion destruction of fortifications, fragmentation of shells, formation of cumulative jets for damaging tanks armor, initiation of nuclear reactions by transition of a nuclear charge to a supercritical state, etc.

The detonation process is of particular importance to understand the phenomena occurring in chemical explosives. According to one of the definitions, the detonation is a stationary process of propagation of a narrow zone of exothermic chemical reactions excited by a shock wave compressing an explosive, which in turn is maintained by the released energy. A complex of a shock wave and a zone of exothermic chemical reactions are called a detonation wave. When developing explosive devices and technologies, the corresponding estimates and calculations are most often based on the hydrodynamic theory (model) of detonation developed in the works of Zeldovich–Neumann–Döring. The initial assumptions of this model are formulated for the case of a plane detonation wave, which obviously does not correspond to the detonation of real charges, which always have finite dimensions.

This leads to concepts of limiting and critical diameters (thicknesses) of charges. However, a discussion of the degree of adequacy and the limits of applicability of the hydrodynamic model continues in the scientific community. A number of effects were found in multiple experiments that do not fit into its framework. For example, there is a discussion of data on chemical reactions behind the Chapman–Jouguet plane (i.e. behind the postulated reaction zone). In experiments with charges of complex geometric shapes, in experiments where the detonation front comes out into the expanding region, or in the presence of cavities or gaps between charges and inert elements, the disturbances in the stationarity of the process are detected (zones of unreacted explosive appear). Particular attention should be paid to detonation processes in charges bounding with inert elements of materials having a sound velocity exceeding detonation velocity. In such cases, shock waves generated by detonation in inert materials can outpace the front of the detonation wave and compress the explosive substance ahead of the front. This leads to a change in the state of explosives and a corresponding change in the kinetics of the detonation transformation. As a result, the stationarity of the detonation process is disrupted, which can lead to changes in its course that are difficult to predict. From a practical point of view, this may cause a decrease or an increase in the effectiveness of explosive technologies. On the other hand, an understanding of the mechanisms of generation, development, and realization of nonstationary effects in detonation can provide a novel approach toward increasing the effectiveness of explosive technologies and/or to purposeful control of detonation processes.

In this monograph we will attempt to systematically describe available data obtained in the experimental study of nonstationary detonation processes in explosive charges containing inert elements made of materials which sound velocity significantly exceeds the detonation velocity. The experimental data is analyzed and compared with simulation results of the corresponding problems in an attempt to explain the physical mechanisms of the observed effects.

The first chapter contains examples of nonstationary propagation of detonation in real situations in the presence of wave perturbations ahead of the detonation front.

The second chapter presents the results of experimental studies of detonation processes in charges containing ceramic rods. The effects of the shock front blurring, the desensitization of explosives under the emerging compression wave, and the possibility of Mach configurations forming on the detonation front are discussed. The experimental results are confirmed by corresponding numerical calculations.

In the third chapter we discuss the results of experimental studies and numerical simulations of nonstationary processes on the contact surface between explosives and inert plates. The data obtained indicates that the detonation near the explosive/ceramic interface has a highly nonstationary nature. This is manifested in inconstancy of pressure values and in differences between the detonation velocity and the stationary detonation parameters. We show that the perturbations arising at the interface affect the front of the detonation wave and change its shape.

The fourth chapter is devoted to the study of peculiarities of detonation processes in cylindrical explosive charges placed in inert shells. Comparing the explosions occurring in copper and ceramic shells, we show both experimentally and by numerical simulations that despite practically the same dynamic rigidity of the shell materials, there are significant differences in wave processes both in detonation products and in shells. This occurs due to the differences in sound velocities between copper and silicon carbide and due to the rapid destruction of the ceramics under explosive loading. A mechanism for transferring perturbations from the periphery to the symmetry axis of cylindrical explosive charges is discussed.

In the fifth chapter, cumulative processes arising in the collapse of cylindrical shells are analyzed. When ceramic tubes are compressed, a stream of brightly glowing particles is formed, which under certain conditions can be called a cumulative jet. The leading part of this stream propagates at a speed approximately two times the detonation velocity and contains the high speed and main parts. This stream of particles displays initiating and penetrative capabilities when acting upon explosives.

The sixth chapter discusses the possibility of application of monolithic and disperse ceramic materials in specific structures that protect dangerous substances during their transportation and storage.

The seventh chapter describes the structures of metals that appear under loading using explosive systems with high‐modulus ceramic elements. The possibility to calculate the parameters of explosive loading by observing the resulting material structures is also considered.

At the end of the monograph, a list of notable publications by the authors on the topic under consideration is presented.

Appendix A contains the information on mechanical properties and behavior peculiarities of a number of high‐modulus materials under impact loading. Special attention is given to the properties of ceramic materials, which were used in the research by the book authors.

Appendix B describes the experimental methods and simulation software, which were used to prepare this book.

This monograph does not pretend to provide exhaustive coverage of the problems mentioned in it. It was prepared based on results of the research carried out by the authors at the Novosibrisk State Technical University in collaboration with scientific groups of the Institute of Problems of Chemical Physics of the Russian Academy of Sciences (Chernogolovka, Moscow Region, Russia), the Bauman Moscow State Technical University (Moscow, Russia), the Lavrentyev Institute of Hydrodynamics of the Siberian Branch of the Russian Academy of Sciences (Novosibirsk, Russia), and the Institute of Pulsed Power Science, Kumamoto University (Kumamoto, Japan). The main results presented in this book were obtained with help of L.A. Merzhievsky, A.V. Utkin, S.V. Razorenov, I.F. Kobylkin, E.F. Gryaznov, A.D. Matrosov, I.A. Stadnichenko, K. Hokamoto, and P. Manikandan. Our pleasant duty is to thank all the colleagues who took part in these studies. Without their participation and consultations, this work would have never been completed.