Whirl flutter optimisation-based solution of twin turboprop aircraft using a full-span model
Whirl flutter is a specific type of flutter instability, relevant for turboprop aircraft, caused by the effect of rotating parts as a propeller or a gas-turbine engine rotor. The proposed optimisation-based analytical procedure is used to determine the critical values of the engine attachment stiffn...
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University of West Bohemia
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doaj-e267776786cd48f9a7c18dc3eae983c92021-09-02T01:03:47ZengUniversity of West BohemiaApplied and Computational Mechanics1802-680X2336-11822017-06-0111152210.24132/acm.2017.324Whirl flutter optimisation-based solution of twin turboprop aircraft using a full-span modelČečrdle J.0Aeronautical Research and Test Institute, Prague, Czech RepublicWhirl flutter is a specific type of flutter instability, relevant for turboprop aircraft, caused by the effect of rotating parts as a propeller or a gas-turbine engine rotor. The proposed optimisation-based analytical procedure is used to determine the critical values of the engine attachment stiffness parameters for the preselected flutter speed. For the half-span model, two design variables are used. The objective function is defined as the minimization of the engine vibration mode frequency sum. Design constraints keep the engine frequency ratio and the flutter stability at the selected velocity. However, application of a full-span model is necessary in some cases. In this case, special models of both symmetric and antisymmetric engine vibrations and four design variables must be used. Design constraints maintain the pitch mode frequency ratio, the yaw mode frequency ratio and the critical mode frequency ratio. Critical modes are dependent on the relation between the rotational direction of both propellers (identical or inverse). A flutter design constraint is applied as well. The described methodology is demonstrated on the application example of a twin-engine commuter aircraft. Demonstrated cases include symmetrical revolutions of propellers for both identical and inverse directions of rotation, cases of single engine failure and single propeller feathering, and finally, cases of unsymmetrical revolutions including the reduced and increased revolutions of a single propeller, for both identical and inverse directions of rotation.https://www.kme.zcu.cz/acm/acm/article/view/324/406whirl flutterfull-span modeloptimisation |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Čečrdle J. |
spellingShingle |
Čečrdle J. Whirl flutter optimisation-based solution of twin turboprop aircraft using a full-span model Applied and Computational Mechanics whirl flutter full-span model optimisation |
author_facet |
Čečrdle J. |
author_sort |
Čečrdle J. |
title |
Whirl flutter optimisation-based solution of twin turboprop aircraft using a full-span model |
title_short |
Whirl flutter optimisation-based solution of twin turboprop aircraft using a full-span model |
title_full |
Whirl flutter optimisation-based solution of twin turboprop aircraft using a full-span model |
title_fullStr |
Whirl flutter optimisation-based solution of twin turboprop aircraft using a full-span model |
title_full_unstemmed |
Whirl flutter optimisation-based solution of twin turboprop aircraft using a full-span model |
title_sort |
whirl flutter optimisation-based solution of twin turboprop aircraft using a full-span model |
publisher |
University of West Bohemia |
series |
Applied and Computational Mechanics |
issn |
1802-680X 2336-1182 |
publishDate |
2017-06-01 |
description |
Whirl flutter is a specific type of flutter instability, relevant for turboprop aircraft, caused by the effect of rotating parts as a propeller or a gas-turbine engine rotor. The proposed optimisation-based analytical procedure is used to determine the critical values of the engine attachment stiffness parameters for the preselected flutter speed. For the half-span model, two design variables are used. The objective function is defined as the minimization of the engine vibration mode frequency sum. Design constraints keep the engine frequency ratio and the flutter stability at the selected velocity. However, application of a full-span model is necessary in some cases. In this case, special models of both symmetric and antisymmetric engine vibrations and four design variables must be used. Design constraints maintain the pitch mode frequency ratio, the yaw mode frequency ratio and the critical mode frequency ratio. Critical modes are dependent on the relation between the rotational direction of both propellers (identical or inverse). A flutter design constraint is applied as well. The described methodology is demonstrated on the application example of a twin-engine commuter aircraft. Demonstrated cases include symmetrical revolutions of propellers for both identical and inverse directions of rotation, cases of single engine failure and single propeller feathering, and finally, cases of unsymmetrical revolutions including the reduced and increased revolutions of a single propeller, for both identical and inverse directions of rotation. |
topic |
whirl flutter full-span model optimisation |
url |
https://www.kme.zcu.cz/acm/acm/article/view/324/406 |
work_keys_str_mv |
AT cecrdlej whirlflutteroptimisationbasedsolutionoftwinturbopropaircraftusingafullspanmodel |
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1721182173681156096 |