1 December 1998
(also see Sections 1.2.1, 9.2.2, 220.127.116.11, 18.104.22.168, 22.214.171.124, 126.96.36.199, and 9.6).
— Amplitude; crack or flaw dimension; measure of flaw size, inches.
— Critical half crack length.
— Initial half crack length.
— Area of cross section, square inches; ratio of alternating stress to mean stress; subscript
“axial”; A basis for mechanical-property values (see Section 188.8.131.52 or Section 184.108.40.206);
“A” ratio, loading amplitude/mean load; or area.
— Strain “A” ratio, strain amplitude/mean strain.
— Model parameter.
— Anderson-Darling test statistic, computed in goodness-of-fit tests for normality or
— American Iron and Steel Institute.
— Aerospace Materials Specification (published by Society of Automotive Engineers, Inc.).
— Air Force-Navy Aeronautical Standard.
— American Society for Testing and Materials.
— Width of sections; subscript “bending”.
— Subscript “bearing”.
— Biaxial ratio (see Equation 220.127.116.11); B-basis for mechanical-property values (see Section
18.104.22.168 or Section 22.214.171.124).
— British thermal unit(s).
— Individual or typical bearing ultimate strength.
— Individual or typical bearing yield strength.
— Fixity coefficient for columns; subscript “compression”.
— Cycles per minute.
— Specific heat; Celsius; Constant.
— Consumable electrode melted.
— Corrosion resistant steel (stainless steel).
— Compact tension.
— Individual or typical compressive yield strength.
— Mathematical operator denoting differential.
D or d
— Diameter, or Durbin Watson statistic; hole or fastener diameter; dimpled hole.
— Degrees of freedom.
— Elongation in percent, a measure of the ductility of a material based on a tension test; unit
deformation or strain; subscript “fatigue or endurance”; the minimum distance from a hole,
center to the edge of the sheet; Engineering strain.
— Elastic strain.
— Plastic strain.
— Ratio of edge distance (center of the