MIL-HDBK-17-3F Volume 3,Chapter 1 General Information The symbols f and m,when used as either subscripts or superscripts,always denote fiber and matrix,respectively. The type of stress(for example,cy-compressive yield)is always used in the superscript position. Direction indicators(for example,x,y,z,1,2,3,etc.)are always used in the subscript position. Ordinal indicators of laminae sequence (e.g.,1,2,3,etc.)are used in the superscript position and must be parenthesized to distinguish them from mathematical exponents. Other indicators may be used in either subscript or superscript position,as appropriate for clarity. Compound symbols(such as,basic symbols plus indicators)which deviate from these rules are shown in their specific form in the following list. The following general symbols and abbreviations are considered standard for use in MIL-HDBK-17. Where exceptions are made,they are noted in the text and tables. -(1)area (m2,in2 -(2)ratio of alternating stress to mean stress -(3)A-basis for mechanical property values -(1)length dimension(mm,in) -(2)acceleration (m/sec2,ft/sec?) -(3)amplitude -(4)crack or flaw dimension(mm,in) B -(1)B-basis for mechanical property values -(2)biaxial ratio Btu -British thermal unit(s) b width dimension(mm,in),e.g.,the width of a bearing or compression panel normal to load, or breadth of beam cross-section C -(1)specific heat (kJ/kg C,Btu/lb F) -(2)Celsius CF centrifugal force (N,Ibf) CPF crossply factor CPT -cured ply thickness(mm,in.) CG -(1)center of mass,"center of gravity" -(2)area or volume centroid E centerline -column buckling end-fixity coefficient c -honeycomb sandwich core depth(mm,in) cpm -cycles per minute D -(1)diameter(mm,in) -(2)hole or fastener diameter(mm,in) -(3)plate stiffness(N-m,Ibf-in) d -mathematical operator denoting differential modulus of elasticity in tension,average ratio of stress to strain for stress below propor- tional limit(GPa,Msi) E -storage modulus (GPa,Msi) E" loss modulus (GPa,Msi) Ee -modulus of elasticity in compression,average ratio of stress to strain for stress below pro- portional limit (GPa,Msi) -modulus of elasticity of honeycomb core normal to sandwich plane(GPa,Msi) Esee secant modulus (GPa,Msi) Etan tangent modulus(GPa,Msi) e -minimum distance from a hole center to the edge of the sheet(mm,in) 1-4MIL-HDBK-17-3F Volume 3, Chapter 1 General Information 1-4 • The symbols f and m, when used as either subscripts or superscripts, always denote fiber and matrix, respectively. • The type of stress (for example, cy - compressive yield) is always used in the superscript position. • Direction indicators (for example, x, y, z, 1, 2, 3, etc.) are always used in the subscript position. • Ordinal indicators of laminae sequence (e.g., 1, 2, 3, etc.) are used in the superscript position and must be parenthesized to distinguish them from mathematical exponents. • Other indicators may be used in either subscript or superscript position, as appropriate for clarity. • Compound symbols (such as, basic symbols plus indicators) which deviate from these rules are shown in their specific form in the following list. The following general symbols and abbreviations are considered standard for use in MIL-HDBK-17. Where exceptions are made, they are noted in the text and tables. A - (1) area (m2 ,in2 ) - (2) ratio of alternating stress to mean stress - (3) A-basis for mechanical property values a - (1) length dimension (mm,in) - (2) acceleration (m/sec2 ,ft/sec2 ) - (3) amplitude - (4) crack or flaw dimension (mm,in) B - (1) B-basis for mechanical property values - (2) biaxial ratio Btu - British thermal unit(s) b - width dimension (mm,in), e.g., the width of a bearing or compression panel normal to load, or breadth of beam cross-section C - (1) specific heat (kJ/kg °C,Btu/lb °F) - (2) Celsius CF - centrifugal force (N,lbf) CPF - crossply factor CPT - cured ply thickness (mm, in.) CG - (1) center of mass, "center of gravity" - (2) area or volume centroid CL - centerline c - column buckling end-fixity coefficient c - honeycomb sandwich core depth (mm,in) cpm - cycles per minute D - (1) diameter (mm,in) - (2) hole or fastener diameter (mm,in) - (3) plate stiffness (N-m,lbf-in) d - mathematical operator denoting differential E - modulus of elasticity in tension, average ratio of stress to strain for stress below propor￾tional limit (GPa,Msi) E' - storage modulus (GPa,Msi) E" - loss modulus (GPa,Msi) Ec - modulus of elasticity in compression, average ratio of stress to strain for stress below pro￾portional limit (GPa,Msi) c ’ E - modulus of elasticity of honeycomb core normal to sandwich plane (GPa,Msi) Esec - secant modulus (GPa,Msi) Etan - tangent modulus (GPa,Msi) e - minimum distance from a hole center to the edge of the sheet (mm,in)