ESDU 97018
Standard fatigue loading sequences.
Abstract:
The three standard loading sequences described in this Data Item are: TWIST (and Mini-Twist), FALSTAFF (and ENSTAFF) and Helix/Felix.The TWIST (Transport WIng STandard) loading sequence was developed to be representative of the stresses in the lower wing skin at the wing root of a transport aircraft, since this has been found to be typically the most fatigue critical location.Mini-TWIST is a shortened version of TWIST for use where limited testing time prohibits the use of the full TWIST. The TWIST Standard loading sequence turning points can be found in VIEWpac TWIST.The FALSTAFF (Fighter Aircraft Loading STAndard For Fatigue) Loading sequence was developed to represent the stresses in the lower wing surface near the wing fuselage joint in tactical aircraft and is based on load factor and strain measurements from five such aircraft. The sequence was derived from a variety of sortie types. The ENSTAFF (ENvironmental FALSTAFF) loading sequence was developed to represent the stresses and environmental conditions expected to be experienced by composite structures in service in a modern fighter aircraft. It combines the FALSTAFF loading sequence with a series of assocaited temperature cycles and a defined moisture content. The FALSTAFF Standard loading sequence turning points can be found in VIEWpac FALSTAFF.Helix and Felix are standard loading sequences for the main rotors of helicopters for hinged or fixed (semi-rigid) rotors respectively. They are based on the measurement of loads taken at the position of maximum flapwise bending moment on the rotor. In the case of articulated rotors this has been found to be at approximately half rotor radius and on the lower surface of the blade. In the case of semi-rigid rotor it has been found to be at the lower surface of the blade root.Indexed under:
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Data Item ESDU 97018 | |
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This Data Item is complemented by the following software:
Name | Details | ||||
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FSTAFFmd |
This program is only available to subscribers. |
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FSTAF |
This program is only available to subscribers. |
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TWIST |
This program is only available to subscribers. |