《纺织复合材料》课程参考文献（Composite Materials Handbook，Volume 3）Chapter 1 GENERAL INFORMATION.pdf_大学文库

MIL-HDBK-17-3F Volume 3,Chapter 1 General Information CHAPTER 1 GENERAL INFORMATION 1.1 INTRODUCTION This standardization handbook has been developed and is maintained as a joint effort of the Depart- ment of Defense and the Federal Aviation Administration,with considerable participation and input from industry,academia and other government agencies.It is oriented toward the standardization of 1)meth- ods used to develop,analyze and publish mechanical property data for composite materials,2)proce- dures to allow design organizations to effectively use the property data published in Volume 2 of this Handbook and other similar databases,and 3)general procedures for designing,analyzing and testing composite structures.In many cases,the standardization is intended to address the needs and require- ments of the customer and regulatory agencies,while providing efficient engineering practices. The standardization of a statistically-based mechanical property data base,procedures used,and overall guidelines for the characterization and use of composite material systems is recognized as being beneficial to both manufacturers and government agencies.A complete characterization of the capabilities of any engineering material system depends on the inherent material physical and chemical composition, which are independent of specific applications.Therefore,at the material system characterization level, the data and guidelines contained in this handbook apply to military and commercial products and provide the technical basis for establishing statistically valid design values acceptable to certifying or procuring agencies. 1.2 PURPOSE,SCOPE,AND ORGANIZATION OF VOLUME 3 For Department of Defense purposes,this handbook is for guidance only.This handbook cannot be cited as a requirement.If it is,the contractor does not have to comply.This mandate is a DoD require- ment only;it is not applicable to the Federal Aviation Administration(FAA)or other government agencies. Volume 3 of MIL-HDBK-17 provides methodologies and lessons learned for the design,analysis, manufacture,and field support of fiber-reinforced,polymeric-matrix composite structures.It also provides guidance on material and process specifications and procedures for utilization of the material data pre- sented in Volume 2.The information provided is consistent with the guidance provided in Volume 1 and intended to be an extensive compilation of the current"best knowledge and practices"of composite ma- terials and structures engineers and scientists from industry,government,and academia.This volume will be continually updated as the"state-of-the-art"of composites technology advances. Volume 3 contains the following chapters,which are arranged in an order,which approximately fol- lows the traditional "building-block"development approach: Chapter 2,Materials and Processes,defines major material systems and processing methods.Ef- fects of various processing parameters on final composite product performance are emphasized. Chapter 3,Quality Control of Production Materials,reviews important issues related to quality control in the production of composite materials.It reviews recommended manufacturing inspection pro- cedures and techniques for material property verification and statistical quality control. Chapter 4,Building Block Approach,outlines the rationale for the traditional multi-level testing and analysis development approach used for many metallic and composite structures programs,particularly in the aerospace industry.It also contains guidance and example building block test programs for various applications,including DoD/NASA prototype and production aircraft,commercial transport aircraft,busi- ness and private aircraft and rotorcraft. 1-1

MIL-HDBK-17-3F Volume 3, Chapter 1 General Information 1-1 CHAPTER 1 GENERAL INFORMATION 1.1 INTRODUCTION This standardization handbook has been developed and is maintained as a joint effort of the Department of Defense and the Federal Aviation Administration, with considerable participation and input from industry, academia and other government agencies. It is oriented toward the standardization of 1) methods used to develop, analyze and publish mechanical property data for composite materials, 2) procedures to allow design organizations to effectively use the property data published in Volume 2 of this Handbook and other similar databases, and 3) general procedures for designing, analyzing and testing composite structures. In many cases, the standardization is intended to address the needs and requirements of the customer and regulatory agencies, while providing efficient engineering practices. The standardization of a statistically-based mechanical property data base, procedures used, and overall guidelines for the characterization and use of composite material systems is recognized as being beneficial to both manufacturers and government agencies. A complete characterization of the capabilities of any engineering material system depends on the inherent material physical and chemical composition, which are independent of specific applications. Therefore, at the material system characterization level, the data and guidelines contained in this handbook apply to military and commercial products and provide the technical basis for establishing statistically valid design values acceptable to certifying or procuring agencies. 1.2 PURPOSE, SCOPE, AND ORGANIZATION OF VOLUME 3 For Department of Defense purposes, this handbook is for guidance only. This handbook cannot be cited as a requirement. If it is, the contractor does not have to comply. This mandate is a DoD requirement only; it is not applicable to the Federal Aviation Administration (FAA) or other government agencies. Volume 3 of MIL-HDBK-17 provides methodologies and lessons learned for the design, analysis, manufacture, and field support of fiber-reinforced, polymeric-matrix composite structures. It also provides guidance on material and process specifications and procedures for utilization of the material data presented in Volume 2. The information provided is consistent with the guidance provided in Volume 1 and intended to be an extensive compilation of the current "best knowledge and practices" of composite materials and structures engineers and scientists from industry, government, and academia. This volume will be continually updated as the "state-of-the-art" of composites technology advances. Volume 3 contains the following chapters, which are arranged in an order, which approximately follows the traditional "building-block" development approach: Chapter 2, Materials and Processes, defines major material systems and processing methods. Effects of various processing parameters on final composite product performance are emphasized. Chapter 3, Quality Control of Production Materials, reviews important issues related to quality control in the production of composite materials. It reviews recommended manufacturing inspection procedures and techniques for material property verification and statistical quality control. Chapter 4, Building Block Approach, outlines the rationale for the traditional multi-level testing and analysis development approach used for many metallic and composite structures programs, particularly in the aerospace industry. It also contains guidance and example building block test programs for various applications, including DoD/NASA prototype and production aircraft, commercial transport aircraft, business and private aircraft and rotorcraft

MIL-HDBK-17-3F Volume 3,Chapter 1 General Information Chapter 5,Design and Analysis,addresses the basic design and analysis of composite laminates. The chapter provides an overview of the current techniques and describes how the various constituent properties contained in Volume 2 are used in the design and analysis of a composite structure.It presents standard analyses to provide a common nomenclature and methodology basis for users of MIL-HDBK-17. The analyses cover lamina and laminate stiffness and strength prediction,and compression buckling methods. Chapter 6,Design and Analysis of Structural Joints,describes accepted design procedures and analytical methods for determining stresses and deformations in structural bonded and mechanically fas- tened joints for composite structures. Chapter 7,Damage Resistance,Durability and Damage Tolerance,provides an extensive discus- sion of these three broad topics,which in general terms relate to the ability of a structure to perform the design functions over the life of the structure.Aircraft damage tolerance requirements and compliance approaches,types of damages and damage inspection are covered in the first sections of the chapter. Following these sections,in each of the three main areas,influencing factors,design issues and guide- lines,testing issues,and analysis methods are covered in detail.Most of the information was developed and is applicable to the aircraft industry,but the general guidelines and basic data provided have applica- tion to many other industries. Chapter 8,Supportability,considers the design for and the design of repairs in composite structures based on maintainability and reliability issues.It provides guidelines to the designer of new structures for considering supportability/maintainability issues,provides information relevant to the design of cost-effective repair procedures,and provides information related to logistical requirements for supporting and repairing composite structures. Chapter 9,Structural Reliability,discusses some of the important factors affecting composite struc- ture reliability including static strength,environmental effects,fatigue,and damage tolerance.It briefly discusses deterministic versus probabilistic design approaches. Chapter 10,Thick-Section Composites,details methods of thick-section laminate analysis, thick-section structural analysis techniques,physical property requirements for three-dimensional analy- sis,experimental property determination techniques,and fabrication process simulation techniques and models for thick laminates Chapter 11,Environmental Management,provides guidance for issues related to recycling and re- use of composite materials and structures. Chapter 12,Lessons Learned,documents a variety of issues related to earlier topics in this volume and provides a depository of knowledge gained from a number of involved companies,agencies,and uni- versities 1.3 SYMBOLS,ABBREVIATIONS,AND SYSTEMS OF UNITS This section defines the symbols and abbreviations which are used within MIL-HDBK-17 and de- scribes the system of units which is maintained.Common usage is maintained where possible.Refer- ences 1.3(a),1.3(b),and 1.3(c)served as primary sources for this information. 1.3.1 Symbols and abbreviations The symbols and abbreviations used in this document are defined in this section with the exception of statistical symbols.These latter symbols are defined in Chapter 8.The lamina/laminate coordinate axes used for all properties and a summary of the mechanical property notation are shown in Figure 1.3.1. 1-2

MIL-HDBK-17-3F Volume 3, Chapter 1 General Information 1-2 Chapter 5, Design and Analysis, addresses the basic design and analysis of composite laminates. The chapter provides an overview of the current techniques and describes how the various constituent properties contained in Volume 2 are used in the design and analysis of a composite structure. It presents standard analyses to provide a common nomenclature and methodology basis for users of MIL-HDBK-17. The analyses cover lamina and laminate stiffness and strength prediction, and compression buckling methods. Chapter 6, Design and Analysis of Structural Joints, describes accepted design procedures and analytical methods for determining stresses and deformations in structural bonded and mechanically fastened joints for composite structures. Chapter 7, Damage Resistance, Durability and Damage Tolerance, provides an extensive discussion of these three broad topics, which in general terms relate to the ability of a structure to perform the design functions over the life of the structure. Aircraft damage tolerance requirements and compliance approaches, types of damages and damage inspection are covered in the first sections of the chapter. Following these sections, in each of the three main areas, influencing factors, design issues and guidelines, testing issues, and analysis methods are covered in detail. Most of the information was developed and is applicable to the aircraft industry, but the general guidelines and basic data provided have application to many other industries. Chapter 8, Supportability, considers the design for and the design of repairs in composite structures based on maintainability and reliability issues. It provides guidelines to the designer of new structures for considering supportability/maintainability issues, provides information relevant to the design of cost-effective repair procedures, and provides information related to logistical requirements for supporting and repairing composite structures. Chapter 9, Structural Reliability, discusses some of the important factors affecting composite structure reliability including static strength, environmental effects, fatigue, and damage tolerance. It briefly discusses deterministic versus probabilistic design approaches. Chapter 10, Thick-Section Composites, details methods of thick-section laminate analysis, thick-section structural analysis techniques, physical property requirements for three-dimensional analysis, experimental property determination techniques, and fabrication process simulation techniques and models for thick laminates. Chapter 11, Environmental Management, provides guidance for issues related to recycling and reuse of composite materials and structures. Chapter 12, Lessons Learned, documents a variety of issues related to earlier topics in this volume and provides a depository of knowledge gained from a number of involved companies, agencies, and universities. 1.3 SYMBOLS, ABBREVIATIONS, AND SYSTEMS OF UNITS This section defines the symbols and abbreviations which are used within MIL-HDBK-17 and describes the system of units which is maintained. Common usage is maintained where possible. References 1.3(a), 1.3(b), and 1.3(c) served as primary sources for this information. 1.3.1 Symbols and abbreviations The symbols and abbreviations used in this document are defined in this section with the exception of statistical symbols. These latter symbols are defined in Chapter 8. The lamina/laminate coordinate axes used for all properties and a summary of the mechanical property notation are shown in Figure 1.3.1

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) 1-4

MIL-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 proportional 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 proportional 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)

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 1-5

MIL-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

MIL-HDBK-17-3F Volume 3, Chapter 1 General Information 1-7 W - (1) weight (N,lbf) - (2) width (mm,in) - (3) Watt x - distance along a coordinate axis Y - nondimensional factor relating component geometry and flaw size y - (1) deflection (due to bending) of elastic curve of a beam (mm,in) - (2) distance from neutral axis to given point - (3) distance along a coordinate axis Z - section modulus, I/y (mm3 ,in3 ) α - coefficient of thermal expansion (m/m/°C,in/in/°F) γ - shear strain (m/m,in/in) ∆ - difference (used as prefix to quantitative symbols) δ - elongation or deflection (mm,in) ε - strain (m/m,in/in) ε e - elastic strain (m/m,in/in) ε p - plastic strain (m/m,in/in) µ - permeability η - plasticity reduction factor [η] - intrinsic viscosity η* - dynamic complex viscosity ν - Poisson's ratio ρ - (1) density (kg/m3,lb/in3) - (2) radius of gyration (mm,in) c ’ ρ - H/C sandwich core density (kg/m3 ,lb/in3 ) Σ - total, summation σ - standard deviation σij, τ ij - stress in j direction on surface whose outer normal is in i direction (i, j = 1, 2, 3 or x, y, z) (MPa,ksi) Τ - applied shear stress (MPa,ksi) ω - angular velocity (radians/s) ∞ - infinity 1.3.1.1 Constituent properties The following symbols apply specifically to the constituent properties of a typical composite material. Ef - Young's modulus of filament material (MPa,ksi) Em - Young's modulus of matrix material (MPa,ksi) x g E - Young's modulus of impregnated glass scrim cloth in the filament direction or in the warp direction of a fabric (MPa,ksi) y g E - Young's modulus of impregnated glass scrim cloth transverse to the filament direction or to the warp direction in a fabric (MPa,ksi) Gf - shear modulus of filament material (MPa,ksi) Gm - shear modulus of matrix (MPa,ksi) xy g G - shear modulus of impregnated glass scrim cloth (MPa,ksi) cx ’ G - shear modulus of sandwich core along X-axis (MPa,ksi) cy ’ G - shear modulus of sandwich core along Y-axis (MPa,ksi) A - filament length (mm,in) α f - coefficient of thermal expansion for filament material (m/m/°C,in/in/°F) α m - coefficient of thermal expansion for matrix material (m/m/°C,in/in/°F)

MIL-HDBK-17-3F Volume 3,Chapter 1 General Information a-coefficient of thermal expansion of impregnated glass scrim cloth in the filament direction or in the warp direction of a fabric(m/m/C,in/in/F) a-coefficient of thermal expansion of impregnated glass scrim cloth transverse to the filament di- rection or to the warp direction in a fabric(m/m/C,in/in/F) -Poisson's ratio of filament material vm -Poisson's ratio of matrix material v-glass scrim cloth Poisson's ratio relating to contraction in the transverse(or fill)direction as a result of extension in the longitudinal(or warp)direction -glass scrim cloth Poisson's ratio relating to contraction in the longitudinal(or warp)direction as a result of extension in the transverse (or fill)direction -applied axial stress at a point,as used in micromechanics analysis(MPa,ksi) 2 applied shear stress at a point,as used in micromechanics analysis(MPa,ksi) 1.3.1.2 Laminae and laminates The following symbols,abbreviations,and notations apply to composite laminae and laminates.At the present time the focus in MIL-HDBK-17 is on laminae properties.However,commonly used nomen- clature for both laminae and laminates are included here to avoid potential confusion. A(j=1,2,6) extensional rigidities (N/m,Ibf/in) B(i5=1,2,6) coupling matrix(N,Ibf) C(ij=1,2,6) elements of stiffness matrix(Pa,psi) D Dy flexural rigidities (N-m,Ibf-in) Dy -twisting rigidity (N-m,lbf-in) D(ij=1,2,6) flexural rigidities(N-m,Ibf-in) E -Young's modulus of lamina parallel to filament or warp direction(GPa,Msi) E2 -Young's modulus of lamina transverse to filament or warp direction(GPa,Msi) -Young's modulus of laminate along x reference axis(GPa,Msi) E Young's modulus of laminate along y reference axis(GPa,Msi) G12 shear modulus of lamina in 12 plane(GPa,Msi) Gxq -shear modulus of laminate in xy reference plane(GPa,Msi) h -thickness of it ply or lamina(mm,in) M,My,Mxy bending and twisting moment components(N-m/m,in-lbf/inin plate and shell analy- sis) 名 number of filaments per unit length per lamina Q Qy shear force parallel to z axis of sections of a plate perpendicular to x and y axes,re- spectively (N/m,Ibf/in) Q(j=1,2,6) reduced stiffness matrix(Pa,psi) Ux,Uy,Uz components of the displacement vector(mm,in) u哏，u9,u2 -components of the displacement vector at the laminate's midsurface(mm,in) V void content(%by volume) Vr -filament content or fiber volume(%by volume) Ve glass scrim cloth content(%by volume) Vm matrix content (by volume) Vx,Vy edge or support shear force(N/m,Ibf/in) Wr filament content(%by weight) Wg glass scrim cloth content(%by weight) m matrix content(%by weight) Ws weight of laminate per unit surface area(N/m2,lbf/in) Q1 -lamina coefficient of thermal expansion along 1 axis(m/m/C,in/in/F) Q2 lamina coefficient of thermal expansion along 2 axis(m/m/C,in/in/F) 1-8

MIL-HDBK-17-3F Volume 3, Chapter 1 General Information 1-8 x g α - coefficient of thermal expansion of impregnated glass scrim cloth in the filament direction or in the warp direction of a fabric (m/m/°C,in/in/°F) y g α - coefficient of thermal expansion of impregnated glass scrim cloth transverse to the filament direction or to the warp direction in a fabric (m/m/°C,in/in/°F) νf - Poisson's ratio of filament material ν m - Poisson's ratio of matrix material xy g ν - glass scrim cloth Poisson's ratio relating to contraction in the transverse (or fill) direction as a result of extension in the longitudinal (or warp) direction yx g ν - glass scrim cloth Poisson's ratio relating to contraction in the longitudinal (or warp) direction as a result of extension in the transverse (or fill) direction σ - applied axial stress at a point, as used in micromechanics analysis (MPa,ksi) τ - applied shear stress at a point, as used in micromechanics analysis (MPa,ksi) 1.3.1.2 Laminae and laminates The following symbols, abbreviations, and notations apply to composite laminae and laminates. At the present time the focus in MIL-HDBK-17 is on laminae properties. However, commonly used nomenclature for both laminae and laminates are included here to avoid potential confusion. Aij (i,j = 1,2,6) - extensional rigidities (N/m,lbf/in) Bij (i,j = 1,2,6) - coupling matrix (N,lbf) Cij (i,j = 1,2,6) - elements of stiffness matrix (Pa,psi) Dx, Dy - flexural rigidities (N-m,lbf-in) Dxy - twisting rigidity (N-m,lbf-in) Dij (i,j = 1,2,6) - flexural rigidities (N-m,lbf-in) E1 - Young's modulus of lamina parallel to filament or warp direction (GPa,Msi) E2 - Young's modulus of lamina transverse to filament or warp direction (GPa,Msi) Ex - Young's modulus of laminate along x reference axis (GPa,Msi) Ey - Young's modulus of laminate along y reference axis (GPa,Msi) G12 - shear modulus of lamina in 12 plane (GPa,Msi) Gxy - shear modulus of laminate in xy reference plane (GPa,Msi) hi - thickness of i th ply or lamina (mm,in) Mx, My, Mxy - bending and twisting moment components (N-m/m, in-lbf/in in plate and shell analysis) nf - number of filaments per unit length per lamina Qx, Qy - shear force parallel to z axis of sections of a plate perpendicular to x and y axes, respectively (N/m,lbf/in) Qij (i,j = 1,2,6) - reduced stiffness matrix (Pa,psi) ux, uy, uz - components of the displacement vector (mm,in) x o y o z o u , u , u - components of the displacement vector at the laminate's midsurface (mm,in) Vv - void content (% by volume) Vf - filament content or fiber volume (% by volume) Vg - glass scrim cloth content (% by volume) Vm - matrix content (% by volume) Vx, Vy - edge or support shear force (N/m,lbf/in) Wf - filament content (% by weight) Wg - glass scrim cloth content (% by weight) Wm - matrix content (% by weight) Ws - weight of laminate per unit surface area (N/m2 ,lbf/in2 ) α 1 - lamina coefficient of thermal expansion along 1 axis (m/m/°C,in/in/°F) α 2 - lamina coefficient of thermal expansion along 2 axis (m/m/°C,in/in/°F)

MIL-HDBK-17-3F Volume 3, Chapter 1 General Information 1-9 α x - laminate coefficient of thermal expansion along general reference x axis (m/m/°C, in/in/°F) α y - laminate coefficient of thermal expansion along general reference y axis (m/m/°C, in/in/°F) α xy - laminate shear distortion coefficient of thermal expansion (m/m/°C,in/in/°F) θ - angular orientation of a lamina in a laminate, i.e., angle between 1 and x axes (°) λ xy - product of ν xy and ν yx ν 12 - Poisson's ratio relating contraction in the 2 direction as a result of extension in the 1 direction1 ν 21 - Poisson's ratio relating contraction in the 1 direction as a result of extension in the 2 direction1 ν xy - Poisson's ratio relating contraction in the y direction as a result of extension in the x direction1 ν yx - Poisson's ratio relating contraction in the x direction as a result of extension in the y direction1 ρ c - density of a single lamina (kg/m3 ,lb/in3 ) c ρ - density of a laminate (kg/m3 ,lb/in3 ) φ - (1) general angular coordinate, (°) - (2) angle between x and load axes in off-axis loading (°) 1.3.1.3 Subscripts The following subscript notations are considered standard in MIL-HDBK-17. 1, 2, 3 - laminae natural orthogonal coordinates (1 is filament or warp direction) A - axial a - (1) adhesive - (2) alternating app - apparent byp - bypass c - composite system, specific filament/matrix composition. Composite as a whole, contrasted to individual constituents. Also, sandwich core when used in conjunction with prime (') - (4) critical cf - centrifugal force e - fatigue or endurance eff - effective eq - equivalent f - filament g - glass scrim cloth H - hoop i - i th position in a sequence L - lateral m - (1) matrix - (2) mean max - maximum min - minimum n - (1) nth (last) position in a sequence - (2) normal p - polar s - symmetric st - stiffener T - transverse 1 The convention for Poisson’s ratio should be checked before comparing different sources as different conventions are used