ASTM F3115/F3115M-15

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: F3115/F3115M −15
Standard Specification for
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Structural Durability for Small Airplanes
ThisstandardisissuedunderthefixeddesignationF3115/F3115M;thenumberimmediatelyfollowingthedesignationindicatestheyear
of original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
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1. Scope 2.2 Federal Aviation Regulations:
14 CFR Part 23 Amendment 62, §§ 23.571 through 23.575,
1.1 This specification addresses the airworthiness require-
23.627
ments related to structural durability for the design of small
airplanes. 2.3 EASA Requirements:
CS 23, §§ 23.571 through 23.575
1.2 This specification was originally conceived for small
CS-VLA
airplanes as defined in the F44 terminology standard but may
find broader applicability. Use of the term aircraft throughout
3. Terminology
this specification is intended to allow the relevant CAA(s) to
accept this standard as a means of compliance as they 3.1 The following are a selection of relevant terms. See
determine it to be appropriate, whether for small airplanes or
Terminology F3060 for more definitions and abbreviations.
for other types of aircraft.
3.2 Definitions:
1.3 Theapplicantforadesignapprovalmustseekindividual
3.2.1 fatigue—the process of progressive localized perma-
guidance from their respective CAA body concerning the use nent structural change occurring in a material subjected to
of this standard as part of a certification plan. For information conditions that produce fluctuating stresses and strains at some
on which CAA regulatory bodies have accepted this standard pointorpoints,whichmayresultincracksorcompletefracture
(in whole or in part) as a means of compliance to their Small after a sufficient number of fluctuations.
Airplane Airworthiness Rules (hereinafter referred to as “the
3.2.2 safe life—the safe-life of a structure is that number of
Rules”), refer to ASTM F44 webpage (www.ASTM.org/
events, such as flights, landings, or flight hours, during which
COMMITTEE/F44.htm) which includes CAA website links.
there is a low probability that the strength will degrade below
its design ultimate value due to fatigue cracking.
1.4 The values stated in either SI units or inch-pound units
are to be regarded separately as standard. The values stated in
3.2.3 S-N or ε-N—Stress-Life (S-N) or Strain-Life (ε-N)
each system may not be exact equivalents; therefore, each
curves depict the magnitude of applied stress (S) or strain (ε)
system shall be used independently of the other. Combining
necessary to develop a fatigue crack in a specimen at a given
values from the two systems may result in non-conformance
life (N), where N is expressed in the number of cyclic
with the standard.
applications of stress or strain.
1.5 This standard does not purport to address all of the
3.2.4 scatter factor—the scatter factor, or life reduction
safety concerns, if any, associated with its use. It is the
factor, is a statistically derived divisor applied to fatigue test
responsibility of the user of this standard to establish appro-
results to account for the variation in fatigue performance of
priate safety and health practices and determine the applica-
built-up or monolithic structures and usage variability. A
bility of regulatory limitations prior to use.
scatter factor can also be used in a fatigue analysis to address
the uncertainties inherent in a fatigue analysis.
2. Referenced Documents
3.2.5 fail safe—fail-safe is the attribute of the structure that
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2.1 ASTM Standards:
permits it to retain its required residual strength for a period of
F3060 Terminology for Aircraft
unrepaired use after the failure or partial failure of a principal
structural element.
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ThisspecificationisunderthejurisdictionofASTMCommitteeF44onGeneral
3.2.6 damage tolerance—damage tolerance is the attribute
Aviation Aircraft and is the direct responsibility of Subcommittee F44.30 on
of the structure that permits it to retain its required residual
Structures.
Current edition approved June 1, 2015. Published September 2015. DOI:
10.1520/F3115_F3115M-15.
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or
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contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM AvailablefromU.S.GovernmentPrintingOfficeSuperintendentofDocuments,
Standards volume information, refer to the standard’s Document Summary page on 732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http://
the ASTM website. www.access.gpo.gov.
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F3115/F3115M − 15
strength for a period of use after the structure has sus
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