MIL-HDBK-17-3F Volume 3.Chapter 1 General Information e/D -ratio of edge distance to hole diameter(bearing strength) F -(1)stress (MPa,ksi) -(2)Fahrenheit Eb bending stress(MPa,ksi) Fcer crushing or crippling stress(upper limit of column stress for failure)(MPa,ksi) Fsu ultimate stress in pure shear(this value represents the average shear stress over the cross-section)(MPa,ksi) FAW fiber areal weight (g/m2,Ib/in?) FV fiber volume (% -(1)internal (or calculated)stress (MPa,ksi) -(2)stress applied to the gross flawed section(MPa,ksi) -(3)creep stress(MPa,ksi) f -internal (or calculated)compressive stress(MPa,ksi) fe -(1)maximum stress at fracture (MPa,ksi) -(2)gross stress limit (for screening elastic fracture data(MPa,ksi) foot.feet 0 -modulus of rigidity(shear modulus)(GPa,Msi) GPa gigapascal(s) g -(1)gram(s) -(2)acceleration due to gravity (m/s2,ft/s2) H/C honeycomb(sandwich) h -height dimension(mm,in)e.g.the height of a beam cross-section hr -hour(s) -area moment of inertia(mm,in) -slope(due to bending)of neutral plane in a beam,in radians in. inch(es) -(1)torsion constant (Ip for round tubes)(m".in) -(2)Joule K -(1)Kelvin -(2)stress intensity factor(MPa/m,ksi/in) -(3)coefficient of thermal conductivity (W/m C,Btu/ft /hr/in/F) -(4)correction factor -(5)dielectric constant -apparent plane strain fracture toughness or residual strength(MPa/m,ksi/in) Ke critical plane strain fracture toughness,a measure of fracture toughness at point of crack growth instability (MPa/m,ksi/in) Kic -plane strain fracture toughness(MPa/m,ksi/in) KN -empirically calculated fatigue notch factor -plate or cylinder shear buckling coefficient K -(1)theoretical elastic stress concentration factor -(2)t/c ratio in H/C sandwich Kv -dielectric strength(KV/mm,V/mil) KxKy -plate or cylinder compression buckling coefficient k strain at unit stress(m/m,in/in) -cylinder,beam,or column length(mm,in) L' effective column length(mm,in) Ib pound M -applied moment or couple (N-m,in-lbf) Mg megagram(s) MPa -megapascal(s) MS military standard M.S -margin of safety MW -molecular weight MWD -molecular weight distribution 1-5MIL-HDBK-17-3F Volume 3, Chapter 1 General Information 1-5 e/D - ratio of edge distance to hole diameter (bearing strength) F - (1) stress (MPa,ksi) - (2) Fahrenheit Fb - bending stress (MPa,ksi) Fccr - crushing or crippling stress (upper limit of column stress for failure) (MPa,ksi) Fsu - ultimate stress in pure shear (this value represents the average shear stress over the cross-section) (MPa,ksi) FAW - fiber areal weight (g/m2 , lb/in2 ) FV - fiber volume (%) f - (1) internal (or calculated) stress (MPa,ksi) - (2) stress applied to the gross flawed section (MPa,ksi) - (3) creep stress (MPa,ksi) f c - internal (or calculated) compressive stress (MPa,ksi) fc - (1) maximum stress at fracture (MPa,ksi) - (2) gross stress limit (for screening elastic fracture data (MPa,ksi) ft - foot, feet G - modulus of rigidity (shear modulus) (GPa,Msi) GPa - gigapascal(s) g - (1) gram(s) - (2) acceleration due to gravity (m/s2 ,ft/s2 ) H/C - honeycomb (sandwich) h - height dimension (mm,in) e.g. the height of a beam cross-section hr - hour(s) I - area moment of inertia (mm4 ,in4 ) i - slope (due to bending) of neutral plane in a beam, in radians in. - inch(es) J - (1) torsion constant (= Ip for round tubes) (m4 ,in4 ) - (2) Joule K - (1) Kelvin - (2) stress intensity factor (MPa/m,ksi/in) - (3) coefficient of thermal conductivity (W/m °C, Btu/ft2 /hr/in/°F) - (4) correction factor - (5) dielectric constant Kapp - apparent plane strain fracture toughness or residual strength (MPa/m,ksi/in) Kc - critical plane strain fracture toughness, a measure of fracture toughness at point of crack growth instability (MPa/m,ksi/in) KIc - plane strain fracture toughness (MPa/m,ksi/in) KN - empirically calculated fatigue notch factor Ks - plate or cylinder shear buckling coefficient Kt - (1) theoretical elastic stress concentration factor - (2) tw/c ratio in H/C sandwich Kv - dielectric strength (KV/mm, V/mil) Kx,Ky - plate or cylinder compression buckling coefficient k - strain at unit stress (m/m,in/in) L - cylinder, beam, or column length (mm,in) L' - effective column length (mm,in) lb - pound M - applied moment or couple (N-m,in-lbf) Mg - megagram(s) MPa - megapascal(s) MS - military standard M.S. - margin of safety MW - molecular weight MWD - molecular weight distribution