Laser Ignition of Energetic Materials (eBook)

S Rafi Ahmad, Michael Cartwright (Autoren)

eBook Download: EPUB

2014
John Wiley & Sons (Verlag)
9781118683507 (ISBN)

Infos

The book gives an introduction to energetic materials and lasers, properties of such materials and the current methods for initiating energetic materials. The following chapters and sections highlight the properties of lasers, and safety aspects of their application. It covers the properties of in-service energetic materials, and also materials with prospects of being used as insensitive ammunitions in future weapon or missiles systems or as detonators in civilian (mining) applications. Because of the diversity of the topics some sections will naturally separate into different levels of expertise and knowledge.

Autor

Dr S Rafi Ahmad founded and led the Centre for Applied Laser Spectroscopy (CALS) within the Department of Applied Science, Security and Resilience, Cranfield University from 1988 to 2013. He has been active for the last 3 decades in managing/supervising many R&D projects and PhD research students in the field of directed laser and applied laser spectroscopy. Dr Ahmad has authored 52 peer-reviewed publications in scientific journals, and co-authored a book with Dr Cartwright. Dr Michael Cartwright works on novel explosive compounds and the design of safer formulations and disposal of time expired and unexploded ordnance. He graduated in Chemistry from London University in the 1960s. His first employment was with the UKAEA at Windscale and Calder Hall establishment examining analytical methods for novel nuclear fuels and processing technologies. He researched on sterilisation methods for the Milton Division of Vick International followed by research in nuclear damage processes in solids and organo-metallic chemistry at the University of Bath before moving to Cranfield University at the Royal Military College of Science in 1986. Dr Cartwright has authored over 80 papers in refereed journals and published conference proceedings, and a co-authored book.

Textauszug

1
Historical Background

1.1 Introduction

Historically, mankind has tried to dominate both fellow human beings and other animals for as long as humans have been around. Some of this domination was achieved by killing other species. This had two aspects; survival and providing food.

Survival was dictated by the fact that many animals regarded humans as excellent sources of food and were quite capable of killing humans. Humans could have two approaches; avoid areas known to contain threatening species or produce devices – weapons – which would enable humans to kill the threatening animals. Humans then developed a taste for the flesh of some of the animals they had killed, thus increasing the sources of food available. As the human population increased, conflict between humans for food and territory increased, and so humans started to fight amongst themselves. By using weapons, humans could overcome physical disadvantages, and the optimum situation was to be able to kill your opponent before they could kill you.

The sword and lance effectively extended the human arm and kept your opponent at bay but, as lances became longer and longer, they became more unwieldy. A remote killing weapon was required. Simple javelins, which could be thrown at the opposition, extended the distance between opponents but required considerable physical stature and skill to achieve the correct flight trajectory for the javelin. Therefore, in order to overcome human physical limitations, mechanical advantage devices were used. The earliest weapons for remote killing were simple slings. These could carry a stone and were capable of accelerating it to high velocity by spinning the sling in a circle. When one of the supporting thongs was released, the stone would travel in an almost straight line from the point of release. Impact of the stone with an animal or human was capable of killing or injuring the animal.

With the development of wood manufacturing skills, bows and arrows became individual weapons or, when grouped together became a lethal hail of arrows which did not depend on the individual accuracy of the archer. The longbow was the ultimate in these weapons. Improved performance came when mankind developed stored energy devices, such as the ballista and crossbows, both of which stored mechanical energy in wooden elements but required winding up before loading the stone or arrow projectile. These overcame the limitations of physical stature required to effectively use the longbow. The ballista, Figure 1.1, was also used to fire barrels of burning oil at the enemy when they had formed shield walls against arrows. The oil container burst on impact and was one of the first deployments of pyrotechnics weapons.

Figure 1.1 Small-scale basic ballista. Reproduced with permission from Cranfield University © 2014.

1.2 The Gunpowder Era

Meanwhile, the Chinese were developing the first chemical explosive gunpowder. The earliest record of this was around 800 AD. Initially, the mixture was for use as a medicine but, as with all good inventions, serendipity intervened and a batch of the medicine fell on to the fire over which it was been cooked; it very rapidly burnt with a flash, smoke and rushing sound. The potential for this was recognized, and the Chinese started to use the mixture as a propellant for their lances/javelins. When attached to the normal throwing spear, these early rockets could extend the useful range of the javelin by as much as a factor of two.

It took about 400 years for the technology to appear in Europe, when a cleric Roger Bacon was credited with discovering the properties of gunpowder. He was so afraid of its properties that he hid the details of the composition in code in religious manuscripts. The recognition of its propellant properties resulted in the manufacture of muzzle-loaded cannons.

An idea of the chronology of the development of the science is given in Table 1.1 on page 3.

Table 1.1 Some significant discoveries in the history of explosives.

Explosive

Credited to

Nationality

Date

Gunpowder

{Anon {R. Bacon

(Probably Chinese) English

Before 1000 c.1246

First battlefield cannon

Italian

c 1326

Crecy bombard

English

1346

Hand cannon

Italian

c 1364

Leonardo's mortar

Leonardo da Vinci

Italian

c 1483

Mercury fulminate

Kunckel

German

c.1690

Picric acid1

Woulff

German

1771

Mercury fulminate percussion cap

Forsyth

Scottish

1825

Nitrocellulose2

{Pelouze {Schonbein

French German

1838 1845

Nitroglycerine

Sobrero

Italian

1846

TNT

Wilbrand

German

1863

The fulminate detonator

Nobel

Swedish

1865

Dynamite

Nobel

Swedish

1867

Ammonium nitrate mixtures

Ohlsson & Norrbin

Swedish

1867

Tetryl

Mertens

German

1877

N.C. propellants3

{Schultze {Vieille

German French

1864 1884

Ballistite

Nobel

Swedish

1883

Cordite

Abel & Dewar

British

1889

Lead azide

Curtius

German

1890

PETN

Rheinisch-Westfaelische Sprengstoff A.G

German

1894

RDX

Henning (patented by Herz)

German German

1899 1920

NTO

von Manchot and Noll

German

1905

Tetrazene

Hoffman & Roth

German

1910

HMX

Slurry explosives

Cook

USA

1957

Emulsion explosives

PBX

1 Explosive properties of Picric acid were not investigated for a further 100 years.

2 Pelouze produced NC but did not understand the chemistry whereas Schonbein correctly identified the chemistry and made some propellant uses.

3 Schultze produced the first successful powdered NC propellants and Vielle was credited with the first NC propellants for rifled barrel guns.

1.3 Cannons, Muskets and Rockets

The barrels of the first cannon systems were simple wooden devices made from hollowed-out tree trunks, which were wrapped with wet ropes for added strength. The development of bronze and cast iron technology led to the production of iron-barrelled guns, such as the Bombard, used at the battle of Crecy in 1346 (shown in Figure 1.2). This weapon used solid projectiles in the form of either suitable stone or cast metal (e.g. iron) spheres. The development of these weapons resulted in the foundation of the Board of Ordinance in 1414. The operators of these weapons were known as Bombardiers – a term still used for an artilleryman with the rank of corporal in the British Army.

In the fifteenth century, cannon were also deployed at sea on warships and these enabled the opposition to be destroyed at distance without needing to engage in hand to hand combat. A number of cannons were deployed along each side of the ship, and a broadside could be loosed at the opposition. Typical cannons are shown in Figure 1.3, which displays a typical army cannon in the foreground and a naval cannon in the background.

Figure 1.2 Crecy bombard 1346. Reproduced with permission from Cranfield University © 2014.

The naval cannon was mounted on a four-wheeled trolley rather than the two wheels of the army. This provided better stability onboard a ship in heavy seas. The iron guns were made of a number of staves, or bars, of iron which were formed into a cylinder around a mandrel. Collars and hoops of wrought iron were heated and slipped over the cylinder. As these cooled, they contracted to form a reinforced tube. Surprisingly, breech-loaded cannon (often regarded as a modern invention, introduced when screw cutting technology was developed during the Industrial Revolution) were available in the early fifteenth century. The early systems used a simple hollow steel tube mounted on a wooden trough, with a space between the end of the metal tube and the end of the wooden support. A closed metal cup containing the propellant charge was then inserted into the gap and rammed into the rear open end of the barrel. The system was then sealed by inserting a wooden plug behind the...

Produkt-Details

• Erscheint lt. Verlag: 27.8.2014
• Sprache: englisch
• Themenwelt: Naturwissenschaften ► Chemie ► Physikalische Chemie
• Themenwelt: Naturwissenschaften ► Chemie ► Technische Chemie
• Themenwelt: Technik
• Schlagworte: acknowledgements xvii historical background • Authors • Bibliography • Characteristics • Chemie • Chemistry • Container • Definition • Explosives • Industrial Chemistry • Initiation • initiations • Laser • laser irradiation • light • Materials Science • Materialwissenschaften • Physics • Physik • References • Research Bibliography • Review • Science • Strength • Technische u. Industrielle Chemie
• ISBN-13: 9781118683507 / 9781118683507