1、Designation: F3114 15Standard Specification forStructures1This standard is issued under the fixed designation F3114; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the y
2、ear of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification addresses the structural requirementsthat apply to all portions of the airframe regardless ofcomponent, system, or structure.1.2 This specification was o
3、riginally conceived for smallairplanes as defined in the F44 terminology standard but mayfind broader applicability. Use of the term aircraft throughoutthis specification is intended to allow the relevant CAA(s) toaccept this standard as a means of compliance as theydetermine it to be appropriate, w
4、hether for small airplanes orfor other types of aircraft.1.3 The applicant for a design approval must seek individualguidance from their respective CAA body concerning the useof this standard as part of a certification plan. For informationon which CAA regulatory bodies have accepted this standard(i
5、n whole or in part) as a means of compliance to their SmallAirplane Airworthiness Rules (hereinafter referred to as “theRules”), refer to ASTM F44 webpage (www.ASTM.org/COMMITTEE/F44.htm) which includes CAA website links.1.4 This standard does not purport to address all of thesafety concerns, if any
6、, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2F3060 Terminology for AircraftF3061 Specification f
7、or Systems and Equipment in SmallAircraftF3083 Specification for Emergency Conditions, OccupantSafety and AccommodationsF3093 Specification for Aeroelasticity RequirementsF3115 Specification for Structural Durability for Small Air-planesF3116 Specification for Design Loads and Conditions3. Terminolo
8、gy3.1 See Terminology F3060 for more definitions and abbre-viations.4. Strength4.1 LoadsStrength requirements are specified in terms oflimit loads (the maximum loads to be expected in service) andultimate loads (limit loads multiplied by prescribed factors ofsafety).4.2 Factor of SafetyUnless otherw
9、ise provided, a factor ofsafety of 1.5 must be used.4.3 Strength and Deformation:4.3.1 The structure must be able to support limit loadswithout detrimental, permanent deformation. At any load up tolimit loads, the deformation may not interfere with safeoperation.4.3.2 The structure must be able to s
10、upport ultimate loadswithout failure for at least three seconds, except local failuresor structural instabilities between limit and ultimate load areacceptable only if the structure can sustain the requiredultimate load for at least three seconds. However when proof ofstrength is shown by dynamic te
11、sts simulating actual loadconditions, the three second limit does not apply.4.4 Proof of Structure:4.4.1 Compliance with the strength and deformation re-quirements of 4.3 must be shown for each critical loadcondition. Structural analysis may be used only if the structureconforms to those for which e
12、xperience has shown this methodto be reliable. In other cases, substantiating load tests must bemade. Dynamic tests, including structural flight tests, areacceptable if the design load conditions have been simulated.4.4.2 Certain parts of the structure must be tested asspecified.4.5 Vibration and Bu
13、ffetingThere must be no vibration orbuffeting severe enough to result in structural damage, andeach part of the airplane must be free from excessive vibration,under any appropriate speed and power conditions up toVD/MD,orVDF/MDFfor turbojets.1This specification is under the jurisdiction ofASTM Commi
14、ttee F44 on GeneralAviation Aircraft and is the direct responsibility of Subcommittee F44.30 onStructures.Current edition approved Nov. 1, 2015. Published December 2015. DOI:10.1520/F3114-15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serv
15、iceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.6 Canard or Tandem Wing Configurations:4.6.1 The forwa
16、rd structure of a canard or tandem wingconfiguration must:4.6.1.1 Meet all requirements of this standard, Specifica-tions F3116, F3093, F3083, and F3115 applicable to a wing;and4.6.1.2 Must meet all requirements applicable to the func-tion performed by these surfaces.4.7 Windshields and Windows:4.7.
17、1 The internal panels of windshields and windows mustbe constructed of a nonsplintering material, such as but notlimited to:4.7.1.1 Nonsplintering safety glass; or4.7.1.2 Synthetic resins.4.7.2 The design of windshields, windows, and canopies inpressurized airplanes must be based on factors peculiar
18、 to highaltitude operation, including:4.7.2.1 The effects of continuous and cyclic pressurizationloadings;4.7.2.2 The inherent characteristics of the material used; and4.7.2.3 The effects of temperatures and temperature gradi-ents.4.7.3 On pressurized airplanes, if certification for operationup to a
19、nd including 25 000 ft is requested, an enclosure canopyincluding a representative part of the installation must besubjected to special tests to account for the combined effects ofcontinuous and cyclic pressurization loadings and flight loads,or compliance with the fail-safe requirements of 4.7.4 mu
20、st beshown.4.7.4 If certification for operation above 25 000 ft isrequested, the windshields, window panels, and canopies mustbe strong enough to withstand the maximum cabin pressuredifferential loads combined with critical aerodynamic pressureand temperature effects, after failure of any load-carry
21、ingelement of the windshield, window panel, or canopy.4.7.5 In the event of any probable single failure, a transpar-ency heating system must be incapable of raising the tempera-ture of any windshield or window to a point where there wouldbe:4.7.5.1 Structural failure that adversely affects the integ
22、rityof the cabin; or4.7.5.2 A danger of fire.4.7.6 In addition, for Level 4 airplanes, the followingapplies:4.7.6.1 Windshield panes directly in front of the pilots in thenormal conduct of their duties, and the supporting structuresfor these panes, must withstand, without penetration, theimpact of a
23、 2-lb bird when the velocity of the airplane (relativeto the bird along the airplanes flight path) is equal to theairplanes maximum approach flap speed.4.8 Landing Gear:4.8.1 For Level 4 airplanes, the following general require-ments for the landing gear apply:4.8.1.1 Each airplane must be designed
24、so that, with theairplane under control, it can be landed on a paved runway withany one or more landing-gear legs not extended withoutsustaining a structural component failure that is likely to causethe spillage of enough fuel to constitute a fire hazard.4.8.1.2 Compliance with the provisions of thi
25、s section maybe shown by analysis or tests, or both.4.9 TestingThe suitability of each questionable designdetail and part having an important bearing on safety inoperations must be established by tests.4.9.1 WingsThe strength of stressed-skin wings must beproven by load tests or by combined structur
26、al analysis andload tests.4.9.2 Control Surfaces:4.9.2.1 Limit load tests of control surfaces are required.These tests must include the horn or fitting to which the controlsystem is attached.4.9.2.2 In structural analyses, rigging loads due to wirebracing must be accounted for in a rational or conse
27、rvativemanner.4.9.3 Pressurization TestsStrength test. The completepressurized cabin, including doors, windows, canopy, andvalves, must be tested as a pressure vessel for the pressuredifferential specified in Specification F3116.5. Mass and Mass Distribution5.1 Load Distribution LimitsThe load distr
28、ibution limitsmay not exceed any of the limits at which the structure isproven.5.2 Leveling MeansThere must be means for determiningwhen the airplane is in a level position on the ground.6. Materials, Processes, and Methods of Fabrication6.1 Materials and Workmanship:6.1.1 The suitability and durabi
29、lity of materials used forparts, the failure of which could adversely affect safety, must:6.1.1.1 Be established by experience or tests;6.1.1.2 Meet approved specifications that ensure their hav-ing the strength and other properties assumed in the designdata; and6.1.1.3 Take into account the effects
30、 of environmentalconditions, such as temperature and humidity, expected inservice.6.1.2 Workmanship must be of a high standard.6.2 Fabrication Methods:6.2.1 The methods of fabrication used must produce con-sistently sound structures. If a fabrication process (such asgluing, spot welding, or heat-tre
31、ating) requires close control toreach this objective, the process must be performed under anapproved process specification.6.2.2 Each new aircraft fabrication method must be substan-tiated by a test program.6.3 Material Strength Properties and Design Values:6.3.1 Material strength properties must be
32、 based on enoughtests of material meeting specifications to establish designvalues on a statistical basis.6.3.1.1 When the manufacturer is unable to provide satis-factory statistical justification, especially in the case of manu-facturing of composite materials, a safety factor may beapplied per 8.5
33、.1 to ensure that statistical values are met forLevel 1 airplanes with:(1) Single engine;F3114 152(2) Maximum certificated take-off weight of not more than750 kgf (1654 lbm);(3) Stalling speed in the landing configuration of not morethan 83 km/h (45 knots) (CAS);(4) Unpressurized fuselage; and(5) No
34、n aerobatic operation.6.3.1.2 The following composite materials are applicablefor 6.3.1.1:(1) Glass fiber or carbon fiber construction in epoxy resin;and(2) Wood construction.36.3.2 Design values must be chosen to minimize the prob-ability of structural failure due to material variability. Except as
35、provided in 6.3.4 or 6.3.1.1 of this section, compliance withthis paragraph must be shown by selecting design values thatensure material strength with the following probability:6.3.2.1 Where applied loads are eventually distributedthrough a single member within an assembly, the failure ofwhich would
36、 result in loss of structural integrity of thecomponent; 99 % probability with 95 % confidence.6.3.2.2 For redundant structure, in which the failure ofindividual elements would result in applied loads being safelydistributed to other load carrying members; 90 % probabilitywith 95 % confidence.6.3.3
37、The effects of temperature on allowable stresses usedfor design in an essential component or structure must beconsidered where thermal effects are significant under normaloperating conditions.6.3.3.1 For airplanes defined in 6.3.1.1 constructed usingcomposite materials defined in 6.3.1.2, compliance
38、 can beshown:(1) At test temperature for white painted surfaces andvertical sunlight of 54C. Test temperature for other coloredsurfaces may be determined by the curve in NASA ConferencePublication 2036, NASAContractor Report 3290 shown in Fig.1.(2) In lieu of 6.3.1.1(1) a safety factor may be applie
39、d per8.5.2 for white painted surfaces at 54C.6.3.4 Design values greater than the guaranteed minimumsrequired by this section may be used where only guaranteedminimum values are normally allowed if a “premium selec-tion” of the material is made in which a specimen of eachindividual item is tested be
40、fore use to determine that the actualstrength properties of that particular item will equal or exceedthose used in design.7. Protection of Structure7.1 Fasteners:7.1.1 Each removable fastener must incorporate two retain-ing devices if the loss of such fastener would precludecontinued safe flight and
41、 landing.3Reference information related to design values of wood structures can be foundin ANC-18, “Design of Wood Aircraft Structures,” issued June 1951 by the AirForce-Navy-Civil Committee on Aircraft Design Criteria (USA).FIG. 1 Test TemperatureF3114 1537.1.2 Fasteners and their locking devices m
42、ust not beadversely affected by the environmental conditions associatedwith the particular installation.7.1.3 No self-locking nut may be used on any bolt subject torotation in operation unless a non-friction locking device isused in addition to the self-locking device.7.2 Protection of StructureEach
43、 part of the structure must:7.2.1 Be suitably protected against deterioration or loss ofstrength in service due to any cause, including:7.2.1.1 Weathering;7.2.1.2 Corrosion; and7.2.1.3 Abrasion; and7.2.2 Have adequate provisions for ventilation and drainage.7.3 Accessibility ProvisionsFor each part
44、that requiresmaintenance, inspection, or other servicing, appropriate meansmust be incorporated into the aircraft design to allow suchservicing to be accomplished.7.4 Fire Protection of Engine Mounts, and Other FlightStructure:7.4.1 Engine mounts, and other flight structure located indesignated fire
45、 zones, or in adjacent areas that would besubjected to the effects of fire in the designated fire zones, mustbe constructed of fireproof material or be shielded so that theyare capable of withstanding the effects of a fire.7.4.2 Engine vibration isolators must incorporate suitablefeatures to ensure
46、that the engine is retained if the non-fireproofportions of the isolators deteriorate from the effects of a fire.8. Special Factors of Safety8.1 Special FactorsThe factor of safety prescribed in 4.2must be multiplied by the highest pertinent special factors ofsafety prescribed in 8.2 through 8.5 for
47、 each part of thestructure whose strength is:8.1.1 Uncertain;8.1.2 Likely to deteriorate in service before normal replace-ment; or8.1.3 Subject to appreciable variability because of uncer-tainties in manufacturing processes or inspection methods.8.2 Casting Factors:8.2.1 GeneralThe factors, tests, a
48、nd inspections specifiedin 8.2.2 through 8.2.4 must be applied in addition to thosenecessary to establish foundry quality control. The inspectionsmust meet approved specifications. Sections 8.2.3 and 8.2.4apply to any structural castings except castings that arepressure tested as parts of hydraulic
49、or other fluid systems anddo not support structural loads.8.2.2 Bearing Stresses and SurfacesThe casting factorsspecified in 8.2.3 and 8.2.4:8.2.2.1 Need not exceed 1.25 with respect to bearingstresses regardless of the method of inspection used; and8.2.2.2 Need not be used with respect to the bearingsurfaces of a part whose bearing factor is larger than theapplicable casting factor.8.2.3 Critical CastingsFor each casting whose failurewould preclude continued safe flight and landing of theairplane or result in serious injury to occupants, the followingapply:8.2.3.1
