(1)
A fatigue strength investigation in which the structure is shown by tests, or by analysis supported by test evidence, to be able to withstand the repeated loads of variable magnitude expected in service; or]
(2)
A fail safe strength investigation in which it is shown by analysis, tests, or both, that catastrophic failure of the structure is not probable after fatigue failure, or obvious partial failure, of a principal structural element, and that the remaining structure is able to withstand a static ultimate load factor of 75 percent of the critical limit load at VC. These loads must be multiplied by a factor of 1.15 unless the dynamic e.ects of failure under static load are otherwise considered.
(3)
The damage tolerance evaluation of Sec. 23.573(b).
(b)
Each evaluation required by this section must :
(1)
Include typical loading spectra(e.g. taxi,ground-air-ground cycles, maneuver, gust);
(2)
Account for any signi.cant e.ects due to the mutual in.uence of aerodynamic surfaces; and
(3)
Consider any signi.cant e.ects from propeller slipstream loading, and bu.et from vortex impingements.
Amdt. 23-48, E.. 03/11/96
FAR 23.573 : Damage tolerance and fatigue evaluation of structure.
(a) Composite airframe structure. Composite airframe structure must be evaluated un-der this paragraph instead of Secs. 23.571 and 23.572. The applicant must eva-luate the composite airframe structure, the failure of which would result in ca-tastrophic loss of the airplane, in each wing (including canards, tandem wings, and winglets), empennage, their carrythrough and attaching structure, moveable control surfaces and their attaching structure, fuselage, and pressure cabin using thedamage-tolerance criteriaprescribedinparagraphs(a)(1) through(a)(4) of this section unless shown to be impractical. If the applicant establishes that damage-tolerance criteria is impractical for a particular structure, the structure must be evaluatedin accordance withparagraphs(a)(1) and(a)(6) of this section.Where bonded joints are used, the structure must also be evaluated in accordance with paragraph(a)(5)of this section.The e.ects of material variability and environmen-tal conditions onthe strength anddurabilityproperties of the composite materials must be accounted for in the evaluations required by this section.
(1) It must be demonstrated by tests, or by analysis supported by tests, that the structureis capable of carrying ultimateload withdamage up to the threshold of detectability considering the inspection procedures employed.
′
Elodie Roux. Septembre 2003
Subpart C : Structure
(2)
The growth rate or no-growth of damage that may occur from fatigue, corro-sion, manufacturing .aws or impact damage, under repeated loads expected in service, must be established by tests or analysis supported by tests.
(3)
The structure must be shown by residual strength tests, or analysis supported by residual strength tests, to be able to withstand critical limit .ight loads, considered as ultimate loads, with the extent of detectable damage consistent with the results of the damage tolerance evaluations. For pressurized cabins, the following loads must be withstood :
(i)
Critical limit .ight loads with the combined e.ects of normal operating pressure and expected external aerodynamicpressures.
(ii)
Theexpected external aerodynamicpressuresin1g .ightcombined with a cabin di.erential pressure equal to 1.1 times the normal operating dif-ferential pressure without any other load.
(4)
Thedamagegrowth,betweeninitialdetectability and the value selectedfor re-sidual strength demonstrations, factored to obtain inspection intervals, must allow development of an inspection program suitable for application by ope-ration and maintenance personnel.
(5)
[For any bonded joint, the failure of which would result in catastrophic loss of the airplane, the limit load capacity must be substantiated by one of the following methods–]
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本文鏈接地址：FAA規(guī)章 美國(guó)聯(lián)邦航空規(guī)章 Federal Aviation Regulations 2(19)
