Explosion, Shock-Wave and High-Strain-Rate Phenomena of Advanced Materials

Materials processing using explosion, shock-wave and high-strain-rate phenomena was developed after WWII, and these explosive forming and welding techniques have since been adopted as an accepted industrial technology. Such extremely high-rate phenomena historically used empirical experiences while the experimental conditions were not well documented due to the difficulties inherent in understanding the real response or behaviour of materials. Based upon the recent development of numerical techniques for analysis and the enriched data available on the behaviour of materials, it is now possible to predict such high-rate phenomena based upon numerical and experimental approaches including optical observation. Explosion, Shock-wave and High-strain-rate Phenomena of Advanced Materials demonstrates the deformation of various materials at high-rate based upon numerical analysis and supported by experimental evidence. The book is recommended for researchers and engineers who would like to learn more about the high-rate effect of materials and those who need to resolve multi-physics problems based on numerical approach. It is also ideal for researchers and engineers interested with explosive and other high-rate processing of materials.

• Presents numerical techniques on the analysis and enriched data on the behavior of materials based upon a numerical approach
• Provides case studies to illustrate the various methods discussed
• Includes mechanical response at high-rates of porous materials

• Language: English
• Publisher: Academic Press
• Release date: Jun 9, 2021
• ISBN: 9780128232378

Book preview

Japan

Preface

It is my great pleasure to issue this book named Explosion, Shock-wave and High-strain-rate Phenomena of Advanced Materials based on the international collaborations made by the contributing authors.

Kumamoto University has a research facility to conduct experiments using explosives, and the intense dynamic loading released by explosions has been used for various materials processing technologies since the 1970s. The Shock Wave and Condensed Matter Research Center was opened in 1999, and an explosion facility with two explosion pits, currently used for various measurement and recovery experiments, was constructed in 2001. The facility is now under the Institute of Industrial Nanomaterials, is unique among the national universities of Japan, and is open for use by researchers.

The authors of each chapter have conducted collaborative research works using the explosion facility over a long period, and the chapters are written based on the collaborative works and the achievements of each author.

The book includes basic issues and some recent research results on explosive forming, welding, and the making of unique porous materials and their responses. I hope the book will be useful for researchers and engineers in related fields.

Kazuyuki Hokamoto

Professor

Institute of Industrial Nanomaterials

Kumamoto University

Kumamoto, Japan

Chapter 1

Basic issues in explosion and other high-rate processing of materials

Kazuyuki Hokamotoa, Hideki Hamashimab

aInstitute of Industrial Nanomaterials, Kumamoto University, Kumamoto, Japan

bKumamoto Industrial Research Institute, Japan

Abstract

Explosion and shock-wave phenomena driven by the detonation of explosives are introduced in terms of the basic issues related to pressure and profile with the time of explosions in both air and water. Since such dynamic phenomena are different from static ones, the understanding of shock waves and their interactions is important. In addition to explosion and shock-wave phenomena, the use of intense dynamic loading for various high-rate processing of materials is explored. Fundamental issues and their practical applications for materials processing technology, including the history of development, are briefly discussed.

Keywords

Explosion; high-rate processing of materials; high energy rate forming; shock wave; underwater shock wave; bubble pulse

1.1 Introduction

This chapter presents basic issues of explosion phenomena and demonstrates some applications of high-rate materials processing technology. It is important to know the basic issues of such explosion phenomena, such as keywords, important phenomena, and scaling law in both air and water. Since the phenomena are dynamic or high-rate processes, which are different from static phenomena, some basic issues are explored in the first part of this chapter.

After discussion of the basic issues, some applications for high-rate materials processing technology are briefly introduced. Take explosive welding as an example: it is normally performed under direct contact of an explosive layer over a metal flyer plate because the detonation pressure is not transferred effectively when there is a space or gap between them. In addition, we sometimes use water as a pressure transmitting medium because it is possible to transmit high pressure as an underwater shock wave to the material to be processed. The use of water as a pressure transmitting medium is technically important for controlling the pressuring condition of the materials to be accelerated. Based on the change of the assembly in dimensions, many pressurizing devices employed for such high-rate processing have been developed and investigated using the explosion facility at Kumamoto University. This book demonstrates numerous case studies based on theoretical and numerical analyses, including the rate effects.

1.2 Explosion phenomena

1.2.1 Explosion in air

1.2.1.1 Blast

When an explosive explodes in air, high-pressure and high-temperature gas is generated by the explosion, which compresses the surrounding air. It spreads out at a very high speed and creates a shock wave. The shock wave spreads, making a spherical surface around the point of initiation, and compresses and flows as a thin layer in the air, which can destroy materials and structures. The pressure rises sharply at the shock front. The fluctuation state of the air caused by the explosion phenomenon of the explosive is called the blast or blast wave.

1.2.1.2 Structure and propagation of a blast wave

Fig. 1.1 shows a typical pressure–time profile (waveform) of a blast arriving at a specific point at a certain distance from the explosion point. The peak over pressure is decreased when the distance from the explosion point is increased. The peak over pressure and the impulse of positive phase are the important parameters for discussing the blasting effect. The important elements of the blast are explained as