Definitions for strains upon ordnance
strain·s upon ordnance

Military Dictionary and GazetteerRate this definition:0.0 / 0 votes

1. strains upon ordnance

   The exterior form of cannon is determined by the variable thickness of the metal which surrounds the bore at different points of its length. In general terms, the thickness is greatest at the seat of the charge, and least at or near the muzzle. This arrangement is made on account of the variable action of the powder and projectile along the bore, and the necessity of disposing the metal in the safest and most economical manner. The pressure at different points may be approximately determined by calculation, or, more accurately, by experiment. In the latter method, the plan generally employed consists in boring a series of small holes through the side of a gun at right angles to its axis at known distances apart. A steel ball is projected from each hole in succession into a target, or ballistic pendulum, by the force of the charge acting through it, and the pressure at the various points is deduced from the velocities communicated to these balls. This method was adopted by Col. Bomford. Instead of the projectile a steel punch may be employed, which is pressed by the force of the charge into a piece of soft copper. (See Pressure-gauge.) The weight necessary to make an equal indentation in the same piece is then ascertained by a testing machine. The strains to which all fire-arms are subjected may be classified as follows: (1) The tangential strain which tends to split the piece open longitudinally, and is similar in its action to the force which bursts the hoops of a barrel. (2) The longitudinal strain which acts to pull the piece apart in the direction of its length. Its action is greatest at or near the bottom of the bore, and least at the muzzle, where it is nothing; these two strains increase the volume of the metal to which they are applied. (3) A strain of compression which acts from the axis outward to crush the truncated wedges of which a unit of length of the piece may be supposed to consist; this strain compresses the metal and enlarges the bore. (4) A transverse strain which acts to break transversely by bending outward the staves of which the piece may be supposed to consist. This strain compresses the metal on the inner and extends it on the outer surface. It is known that rupture will take place due to the tangential strain alone, when three times the pressure upon a unit of surface of the bore is greater than twice the tensile strength. Due to the longitudinal strain alone, rupture will take place in the direction of the length, when the pressure is greater than twice the tensile strength; and if the transverse strain alone is considered, rupture will take place when twice the pressure is greater than three times the tensile strength. It therefore appears that the tendency to rupture is greater from the action of the tangential force than from any other, and for lengths above two, or perhaps three calibers, the tangential resistance may be said to act alone, as the aid derived from the transverse resistance will be but trifling for greater lengths of bore; but for lengths of bore less than two calibers, this resistance will be aided by both the transverse and the longitudinal resistance. Every piece should therefore have sufficient thickness of breech to prevent splitting through the latter; after this point has been attained, any additional thickness of breech adds nothing to the strength of the piece. It therefore appears that a fire-arm is strongest at or near the bottom of the bore, and that its strength is diminished rapidly as the length of the bore increases to a certain point (probably not more than three calibers from the bottom); after which, for equal thickness of metal, its strength becomes sensibly uniform. The metals of which cannon are made being crystalline in structure, the size and arrangement of the crystals have an important influence on its strength to resist a particular force; and a metal will have the greatest strength with reference to a particular force when its crystals are small, and the principal faces are parallel to the straining force, if it be one of extension, and perpendicular to it, if it be one of compression. The position of the principal crystalline faces of a cooling solid is found to be perpendicular to the cooling surface; the result of this arrangement of crystals is to create planes of weakness where the different systems of crystals intersect. The effect of this law upon cannons, it has been discovered, is to render radial specimens more tenacious than those cut tangentially from the same gun. The manner and rapidity of cooling have also a great effect upon the ability of cannon to resist strains, and as all solid bodies contract their size in the operation of cooling, it follows that if the different parts of a cannon cool unequally, it will change its form, provided it be not restrained by the presence of a superior force. If it be so restrained, the contractile force will diminish the adhesion of the parts by an amount which depends on the rate of

How to pronounce strains upon ordnance?

1. Alex

   US English

   David

   US English

   Mark

   US English

   Daniel

   British

   Libby

   British

   Mia

   British

   Karen

   Australian

   Hayley

   Australian

   Natasha

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   Veena

   Indian

   Priya

   Indian

   Neerja

   Indian

   Zira

   US English

   Oliver

   British

   Wendy

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   Fred

   US English

   Tessa

   South African

How to say strains upon ordnance in sign language?

Numerology

1. Chaldean Numerology

   The numerical value of strains upon ordnance in Chaldean Numerology is: 5

2. Pythagorean Numerology

   The numerical value of strains upon ordnance in Pythagorean Numerology is: 6

References

1. ^ Military Dictionary and Gazetteer
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