The number of amperes flowing through a circuit. Analogous to the flow of
gallons per minute in a water pipe. Crispin
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[\B]strength of materials[\N]
In a solid, the force per unit area, acting on any surface within it, and
variously expressed as pounds or tons per square inch, or dynes or
kilograms per square centimeter; also, by extension, the external pressure
that creates the internal force. The stress at any point is mathematically
defined by nine values: three to specify the normal components and six to
specify the shear components, relative to three mutually perpendicular
reference axes. CF:strain
shear stress. AGI
Determination of the stresses in the component parts of a structure when
subjected to load. See also:photoelasticity
A Mohr circle that reveals the distribution of stress. Hammond
Failure by cracking under combined action of corrosion and stress, either
external (applied) or internal (residual). Cracking may be either
intergranular or transgranular, depending on metal and corrosive medium.
ASM, 1
The difference between the greatest and least of the three principal
stresses. AGI
The zone of extra stress around a cylindrical hole being actually
cylindrical in form. Syn:ring stress
The state of stress, either homogeneous or varying from point to point, in
a given domain. AGI
An instrument designed to measure pressure changes within rock as a result
of mining operations. The instrument consists of a tongue of steel
containing a groove filled with glycerin. When pressure is exerted upon
the external surface of the tongue, the glycerin is partially squeezed
from the groove and exerts pressure on a diaphram, which accordingly
bulges outwards. A strain gage is cemented on the outer wall of the
diaphragm, and as the curvature increases and the gage is strained, so
does its resistance vary. Issacson
A term suggested for minerals such as chlorite, chloritoid, talc, albite,
epidote, amphiboles, and kyanite, whose formation in metamorphosed rocks
is favored by shearing stress. CF:antistress mineral
A curve obtained in fatigue tests by subjecting a series of specimens of a
given material to different ranges of stress and plotting the range of
stress against the number of cycles required to produce failure. In steel
and many other metals, there is a limiting range of stress below which
failure will not be produced even by an indefinite number of cycles.
CTD
Stress rings are force lines drawn on the cross section of an excavation
to indicate the distribution of the additional stress in the rock caused
by that excavation. Spalding
The solid figure formed by surfaces bounding vectors drawn at all points
of the cross section of a member and representing the unit normal stress
at each such point. The stress solid gives a picture of the stress
distribution on a section. Roark
A curve similar to a load extension curve, except that the load is divided
by the original cross-sectional area of the test piece and expressed as
tons or pounds per square inch, while the extension is divided by the
length over which it is measured and expressed in inches per inch.
See also:load-extension curve
a. A graph on which is plotted stress vs. strain. Such a graph may be
constructed in any test during which frequent or continuous measurements
of both stress and strain are made. It is commonly constructed for the
compression, tension, and torsion tests. It is usually necessary for the
determination of deformation energy, elastic limit, modulus of elasticity,
modulus of rigidity, proportional limit, and yield strength. It is often
useful in determination of elongation, modulus of rupture, ultimate
strength and related properties. Hunt
b. The curve obtained by plotting unit stresses as ordinates against
corresponding unit strains as abscissas. Syn:stress diagram
Roark
A line (in a stressed body) tangent to the direction of one of the
principal stresses at every point through which it passes.
Syn:isostatic
This is the zone of additional stress in the rock surrounding and caused
by a stoped area. Spalding
The system of mining coal by headings or narrow work.
See also:bord-and-pillar
A particular direction or course; as, the stretch of a coal seam.
Standard, 2
a. A bar used for roof support on a roadway, which is either wedged
against or pocketed into the sides of the roadway and not supported by
legs or struts. TIME
b. A bar fixed across a narrow working place or tunnel to support a rock
drill. CTD
c. A main backing deal or longitudinal bar in contact with three or more
support bars or girders. Mason