Definitions /Dictionary/Glossary - nptel

Stress: The intensity at a point in a body of the forces or components of forces that act on a
given plane through the point. Stress is expressed in force per unit area (pounds-force per square
inch, megapascals, etc.).
Stress Concentration: The magnification of applied stress in the region of a notch, void, hole,
or inclusion.
Stress Corrosion: Preferential attack of areas under stress in a corrosive environment, where
such an environment alone would not have caused corrosion.
Stress Crack: External or internal cracks in a composite caused by tensile stresses; cracking can
be present internally, externally or in combination.
Stress Relaxation: The time dependent decrease in stress in a solid under given constraint
conditions.
Stress-Strain Curve (Diagram): A graphical representation showing the relationship between
the change in dimension of the specimen in the direction of the externally applied stress and the
magnitude of the applied stress. Values of stress usually are plotted as ordinates (vertically) and
strain values as abscissa (horizontally).
Stress-Strain: Stiffness, expressed in pounds per square inch or kilograms per square
centimeter, at a given strain.
Structural Adhesive: An adhesive used for transferring loads between adherends.
Structural Bond: A bond joining load-bearing components of an assembly.
Structural Element: a generic element of a more complex structural member (for example,
skin, stringer, shear panels, sandwich panels, joints, or splices).
Structural Glass
A magnesia/alumina/silicate glass reinforcement designed to provide very high tensile strength.
Structural Repair Manual (SRM)
Document prepared by an OEM that designates original structural materials (both composite and
metal) used for specific aircraft. It usually includes schematics for all parts and listings of
fastener types and adhesives. It also suggests general repair methodology so that structural
integrity can be maintained.
Styrene Monomer: An unsaturated hydrocarbon, used in plastics. In polyester, it is a co-reactant
diluent.
Substrate: A material upon the surface of which an adhesive-containing substance is spread for
any purpose, such as bonding or coating.