MIL-HDBK-17-1F Volume 1,Chapter 1 Objectives 1.4.2 Source of information The information contained in MIL-HDBK-17 is obtained from materials producers and fabricators,the aerospace industry,reports on government-sponsored research,the open literature,direct contacts with researchers,and from participants in MIL-HDBK-17 coordination activities.All information published in this document has been coordinated and reviewed by representatives from industry,the US Army,the US Navy,the US Air Force,NASA,and the US Federal Aviation Administration.Every effort has been made to reflect the most up-to-date information on the use of composite materials,with particular emphasis on use of composites in structures.The handbook is continually reviewed and revised to keep current with the state-of-the-art and insure completeness and accuracy. 1.4.3 Use of data and guidelines in applications All data contained herein are based on small-scale test specimens for specific environmental condi- tions,largely limited to uniaxial quasi-static loading.'It is the user's responsibility to determine if hand- book data is appropriate for a given application,and if selected,to translate or scale the data as neces- sary for use: in a multi-directional laminate on a structure of different characteristic size and geometry. under a multi-directional stress state. when exposed to a different environment,and/or when subjected to non-static loading. Further discussions of these and other issues are provided in Volume 3.Specific uses of handbook data are beyond the scope and responsibility of MIL-HDBK-17,and applicability and interpretation of specific provisions of this handbook may require approval by an appropriate procurement or certification agency. 1.4.4 Strength properties and allowables terminology The handbook intent is to provide guidelines for generating material property data,including statisti- cally-based strength data at environmental extremes that bracket most intermediate application-specific environments.The philosophy is to avoid having application-specific issues govern generic material property characterization programs.If data are also available at intermediate environmental conditions, they can be used to more completely define the relationship between the property and the effect of the environment on that property.However,in some cases an environmental limit for a composite material system may be application dependent,and in others,data at environmental limits may not be available. Available statistically-based strength data are tabulated in Volume 2.These data are useful as a starting point for establishing structural design allowable values when stress and strength analysis capa- bilities permit lamina-level margin-of-safety calculations.For such cases the MIL-HDBK-17 strength basis value may also be termed a material design allowable.Depending on the application,some structural design allowables may have to be empirically determined from additional laminate,element,or higher- level test data not provided by MIL-HDBK-17. 1.4.5 Use of references While many references are provided at the end of each chapter,note that the information in these citations may not necessarily comply in every respect either with the general guidelines for data develop- ment or with the specific requirements for publication of data in the handbook.The references are simply Unless otherwise noted,tests were conducted in conformance with the particular test method noted.The emphasis is on data ob- tained from ASTM standard test methods for advanced composites,but where an ASTM test method has been deemed inappropri- ate or is not yet available,or when data from a nonstandard but commonly practiced test procedure is available,then data from a non-standard test method may have been accepted for publication.The specific test method used is noted in the data documenta- tion.See also the statement on test method acceptance criteria in Section 2.5.5. 1-16
MIL-HDBK-17-1F Volume 1, Chapter 1 Objectives 1-16 1.4.2 Source of information The information contained in MIL-HDBK-17 is obtained from materials producers and fabricators, the aerospace industry, reports on government-sponsored research, the open literature, direct contacts with researchers, and from participants in MIL-HDBK-17 coordination activities. All information published in this document has been coordinated and reviewed by representatives from industry, the US Army, the US Navy, the US Air Force, NASA, and the US Federal Aviation Administration. Every effort has been made to reflect the most up-to-date information on the use of composite materials, with particular emphasis on use of composites in structures. The handbook is continually reviewed and revised to keep current with the state-of-the-art and insure completeness and accuracy. 1.4.3 Use of data and guidelines in applications All data contained herein are based on small-scale test specimens for specific environmental conditions, largely limited to uniaxial quasi-static loading.1 It is the user's responsibility to determine if handbook data is appropriate for a given application, and if selected, to translate or scale the data as necessary for use: • in a multi-directional laminate, • on a structure of different characteristic size and geometry, • under a multi-directional stress state, • when exposed to a different environment, and/or • when subjected to non-static loading. Further discussions of these and other issues are provided in Volume 3. Specific uses of handbook data are beyond the scope and responsibility of MIL-HDBK-17, and applicability and interpretation of specific provisions of this handbook may require approval by an appropriate procurement or certification agency. 1.4.4 Strength properties and allowables terminology The handbook intent is to provide guidelines for generating material property data, including statistically-based strength data at environmental extremes that bracket most intermediate application-specific environments. The philosophy is to avoid having application-specific issues govern generic material property characterization programs. If data are also available at intermediate environmental conditions, they can be used to more completely define the relationship between the property and the effect of the environment on that property. However, in some cases an environmental limit for a composite material system may be application dependent, and in others, data at environmental limits may not be available. Available statistically-based strength data are tabulated in Volume 2. These data are useful as a starting point for establishing structural design allowable values when stress and strength analysis capabilities permit lamina-level margin-of-safety calculations. For such cases the MIL-HDBK-17 strength basis value may also be termed a material design allowable. Depending on the application, some structural design allowables may have to be empirically determined from additional laminate, element, or higherlevel test data not provided by MIL-HDBK-17. 1.4.5 Use of references While many references are provided at the end of each chapter, note that the information in these citations may not necessarily comply in every respect either with the general guidelines for data development or with the specific requirements for publication of data in the handbook. The references are simply 1 Unless otherwise noted, tests were conducted in conformance with the particular test method noted. The emphasis is on data obtained from ASTM standard test methods for advanced composites, but where an ASTM test method has been deemed inappropriate or is not yet available, or when data from a nonstandard but commonly practiced test procedure is available, then data from a non-standard test method may have been accepted for publication. The specific test method used is noted in the data documentation. See also the statement on test method acceptance criteria in Section 2.5.5
MIL-HDBK-17-1F Volume 1,Chapter 1 Objectives intended to be helpful,but not necessarily complete or authoritative sources of additional related informa- tion on specific subject areas. 1.4.6 Use of tradenames and product names Use of tradenames or proprietary product names does not constitute an endorsement of those prod- ucts by the US Government or by the MIL-HDBK-17 Coordination Group. 1.4.7 Toxicity,health hazards,and safety Certain processing and test methods discussed in MIL-HDBK-17 may involve hazardous materials, operations,or equipment.These methods may not address safety problems,if any,associated with their use.It is the responsibility of the user of these methods to establish appropriate safety and health prac- tices and to determine the applicability of regulatory limitations prior to use.The user is referred to the Advanced Composite Materials US Army Interim Health and Safety Guidance for a discussion of the health and safety issues involved in the processing and use of composite materials.This document is generated by the US Army Environmental Hygiene Agency,Aberdeen Proving Ground,MD.Material manufacturers,as well as various composites user groups,may also provide guidance on health and safety issues pertinent to composite materials. 1.4.8 Ozone depleting chemicals Restrictions on the use of ozone depleting chemicals are detailed in the US Clean Air Act of 1991. 1.5 APPROVAL PROCEDURES The content of the handbook is developed and approved by the MIL-HDBK-17 Coordination Group, which meets twice yearly to consider changes and additions to the handbook.This Group consists of the handbook Co-Chairs,Coordinator,Secretariat,Working Group Chairs,and the active Working Group par- ticipants,which include representatives from various US and international procuring and certifying agen- cies,in addition to the producing industries and academic and research institutions.MIL-HDBK-17 Coor- dination Group meetings are announced to participants by mail about eight weeks prior to the scheduled meeting date,and minutes of the meetings are mailed eight weeks following the close of the meeting While each of the Working Groups functions similarly,they are of three types:Executive,a single Working Group with oversight responsibility composed of the Working Group Chairs,the handbook Co- Chairs,Coordinator,and Secretariat;Standing,including Data Review,Guidelines,Materials and Proc- essing,Statistics,and Testing Working Groups;and Specialty,which varies with time but currently in- cludes the Braiding and Filament Winding,Supportability,Structural Joints,and Thick-Sections Working Groups.The makeup and organization of the Coordination Group and Working Groups,as well as the procedures followed for document change approval,are summarized in the MIL-HDBK-17 Coordination Group Member's Guide,separately published and available from either the Coordinator or Secretariat. Proposals for addition to,deletion from,or modification to the handbook should be submitted to both the appropriate Working Group and the Secretariat well in advance of the announcement mailing date, and should include specific notation of the proposed changes and adequate documentation of supporting data or analytical procedures.Reproducible copies of figures,drawings,or photographs proposed for publication in the document should be furnished to the Secretariat.Following approval by the appropriate Working Group,the proposed changes are published in the next minutes of the Coordination Group,in a special section of the minutes called the "yellow pages",and all participants are allowed comment on the proposed changes.If no substantive comments are received on any individual item by the posted re- sponse date,then that item is considered approved by the Coordination Group and is considered effective as of that date.(Prior to publication in the next revision of the handbook the collected changes are re- viewed by various branches of the US DOD.Additional proposals for revision may result from this US DOD review.) 1-17
MIL-HDBK-17-1F Volume 1, Chapter 1 Objectives 1-17 intended to be helpful, but not necessarily complete or authoritative sources of additional related information on specific subject areas. 1.4.6 Use of tradenames and product names Use of tradenames or proprietary product names does not constitute an endorsement of those products by the US Government or by the MIL-HDBK-17 Coordination Group. 1.4.7 Toxicity, health hazards, and safety Certain processing and test methods discussed in MIL-HDBK-17 may involve hazardous materials, operations, or equipment. These methods may not address safety problems, if any, associated with their use. It is the responsibility of the user of these methods to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use. The user is referred to the Advanced Composite Materials US Army Interim Health and Safety Guidance for a discussion of the health and safety issues involved in the processing and use of composite materials. This document is generated by the US Army Environmental Hygiene Agency, Aberdeen Proving Ground, MD. Material manufacturers, as well as various composites user groups, may also provide guidance on health and safety issues pertinent to composite materials. 1.4.8 Ozone depleting chemicals Restrictions on the use of ozone depleting chemicals are detailed in the US Clean Air Act of 1991. 1.5 APPROVAL PROCEDURES The content of the handbook is developed and approved by the MIL-HDBK-17 Coordination Group, which meets twice yearly to consider changes and additions to the handbook. This Group consists of the handbook Co-Chairs, Coordinator, Secretariat, Working Group Chairs, and the active Working Group participants, which include representatives from various US and international procuring and certifying agencies, in addition to the producing industries and academic and research institutions. MIL-HDBK-17 Coordination Group meetings are announced to participants by mail about eight weeks prior to the scheduled meeting date, and minutes of the meetings are mailed eight weeks following the close of the meeting. While each of the Working Groups functions similarly, they are of three types: Executive, a single Working Group with oversight responsibility composed of the Working Group Chairs, the handbook CoChairs, Coordinator, and Secretariat; Standing, including Data Review, Guidelines, Materials and Processing, Statistics, and Testing Working Groups; and Specialty, which varies with time but currently includes the Braiding and Filament Winding, Supportability, Structural Joints, and Thick-Sections Working Groups. The makeup and organization of the Coordination Group and Working Groups, as well as the procedures followed for document change approval, are summarized in the MIL-HDBK-17 Coordination Group Member's Guide, separately published and available from either the Coordinator or Secretariat. Proposals for addition to, deletion from, or modification to the handbook should be submitted to both the appropriate Working Group and the Secretariat well in advance of the announcement mailing date, and should include specific notation of the proposed changes and adequate documentation of supporting data or analytical procedures. Reproducible copies of figures, drawings, or photographs proposed for publication in the document should be furnished to the Secretariat. Following approval by the appropriate Working Group, the proposed changes are published in the next minutes of the Coordination Group, in a special section of the minutes called the "yellow pages", and all participants are allowed comment on the proposed changes. If no substantive comments are received on any individual item by the posted response date, then that item is considered approved by the Coordination Group and is considered effective as of that date. (Prior to publication in the next revision of the handbook the collected changes are reviewed by various branches of the US DOD. Additional proposals for revision may result from this US DOD review.)