Design and Stress Analysis of Extraterrestrial ... - The Black Vault

Stress is the intensity of the internal forces of elasticity,
corresponding to a given elementary area of a certain cross sction.
Stress is calculated for this area as the ratio of the absolute
value of force to the size of the area on which it acts, i.e.,
as the force which occurs per unit of area.
*1 Normal stress ik is that component of stress which actsS
perpendicularly to the area; the subscript k designates the direction
of normal to the area. For example, if the area is perpendicular
to axis x, normal stress acting on this area is designated a•
Tangential stress T is the component of stress acting:along I
the area; the subscript k also indicates the direction of normal to
tha area, while the subscript i is'the direction of ti.e vector of
tangential stress; the dimension of stress N/m (or kg/cm2).
Under the effect of external forces and stress which occur,
the dimeusions of the part change somewhat; it is deformed.
Deformation is the change in linear or' angular dimensions of
a part; usually these changes are very insignificant as compared
with the part's dimensions.
Absolute elongation, i.e., change in the lineardimensions Ik,
is designated AZk. It is positive during extension and negative..
during compressioni.
Relative elongation Ek is the r~atio: ek. = Alk/Z; the subscript
k indicates in
what direction elongation id occurring.
Relative shear y is the angle by which the original right angle
between two selected directions in the part changes during its
deformation. If these mutually perpendicular directions are
designated x and y, relative shear y is given the subscript xy.
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