Brisance (; ) is the shattering capability of a

high explosive An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An exp ...

, determined mainly by its detonation pressure.

Application

Brisance is of practical importance in

explosives engineering Explosives engineering is the field of science and engineering which is related to examining the behavior and usage of explosive materials. Topics Some of the topics that explosives engineers study, research, and work on include: * Developmen ...

for determining the effectiveness of an explosion in blasting and quarrying, and in weaponry such as fragmenting shells,

bomb A bomb is an explosive weapon that uses the exothermic reaction of an explosive material to provide an extremely sudden and violent release of energy. Detonations inflict damage principally through ground- and atmosphere-transmitted mechan ...

casings,

grenade A grenade is a small explosive weapon typically thrown by hand (also called hand grenade), but can also refer to a Shell (projectile), shell (explosive projectile) shot from the muzzle of a rifle (as a rifle grenade) or a grenade launcher. A mod ...

s, and

plastic explosive Plastic explosive is a soft and hand-moldable solid form of explosive material. Within the field of explosives engineering, plastic explosives are also known as putty explosives or blastics. Plastic explosives are especially suited for explos ...

s. The sand crush test and Trauzl lead block test are commonly used to determine the relative brisance in comparison to TNT (which is considered a standard reference for many purposes). The value of brisance depends on the application. At one extreme, if an explosive is to be used for propulsion, e.g. by driving a

piston A piston is a component of reciprocating engines, reciprocating pumps, gas compressors, hydraulic cylinders and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder (engine), cylinder a ...

or a bullet, brisance is likely to be undesirable, because the objective will be to ''move'' the load, not to shatter it or the engine or firearm, nor to produce a loud report. Such propulsive charges are designed to burn controllably, such as carburetted fuel/air mixes in vehicle piston engines, or

nitrocellulose Nitrocellulose (also known as cellulose nitrate, flash paper, flash cotton, guncotton, pyroxylin and flash string, depending on form) is a highly flammable compound formed by nitrating cellulose through exposure to a mixture of nitric acid and ...

fibres or grains of controlled textures in

firearm A firearm is any type of gun that uses an explosive charge and is designed to be readily carried and operated by an individual. The term is legally defined further in different countries (see legal definitions). The first firearms originate ...

cartridges. For certain types of blasting, as in some

civil engineering Civil engineering is a regulation and licensure in engineering, professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including public works such as roads ...

works, the objective is to loosen the undesired material with the least amount of explosion and expense, both in explosive and safety precautions. Similarly, in quarrying a product such as

slate Slate is a fine-grained, foliated, homogeneous, metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade, regional metamorphism. It is the finest-grained foliated metamorphic ro ...

, in which the objective is to loosen it from surrounding rock with as little damage as possible, no more brisance than is necessary to split off the valuable product profitably, without unacceptable waste, is desired. For this purpose blasting powder of ''low'' brisance is necessary.PIDDOCK, S. (2007). Slate, slate, everywhere slate: The cultural landscapes of the Willunga slate quarries, South Australia. Australasian Historical Archaeology, 25, 5-18. Retrieved from http://www.jstor.org/stable/29544573 In shattering hard rock or military defences, high brisance generally is necessary, so

s with extremely high

detonation velocity Explosive velocity, also known as detonation velocity or velocity of detonation (VoD), is the velocity at which the shock wave front travels through a detonated explosive. Explosive velocities are always higher than the local speed of sound in t ...

are used as far as is practical. One of the most brisant of the conventional explosives is cyclotrimethylene trinitramine (also known as

RDX RDX (Research Department Explosive or Royal Demolition Explosive) or hexogen, among other names, is an organic compound with the formula (CH2N2O2)3. It is white, odorless, and tasteless, widely used as an explosive. Chemically, it is classified ...

or Hexogen). RDX is the explosive agent in the plastic explosive commonly known as C-4, constituting 91% RDX by mass. Fragmentation occurs by the action of the transmitted shock wave, the strength of which depends on the detonation pressure of the explosive. Generally, the higher this pressure, the finer the fragments generated. High detonation pressure correlates with high detonation velocity, the speed at which the detonation wave propagates through the explosive, but not necessarily with the explosive's total energy (or work capacity), some of which may be released after passage of the detonation wave. A more brisant explosive, therefore, projects smaller fragments but not necessarily at a higher velocity than a less brisant one.

References

{{Reflist * A. Bailey & S.G. Murray, ''Explosives, Propellants & Pyrotechnics'', Brassey's (UK) Ltd., London, 1989. Explosives

Application

See also

References