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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Grazing bifurcation in aeroelastic systems with freeplay nonlinearity

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Autor(es):
Vasconcellos, R. [1] ; Abdelkefi, A. [2] ; Hajj, M. R. [2] ; Marques, F. D. [1]
Número total de Autores: 4
Afiliação do(s) autor(es):
[1] Univ Sao Paulo, Engn Sch Sao Carlos, Lab Aeroelast, BR-13566590 Sao Carlos, SP - Brazil
[2] Virginia Tech, Dept Engn Sci & Mech, Blacksburg, VA 24061 - USA
Número total de Afiliações: 2
Tipo de documento: Artigo Científico
Fonte: COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION; v. 19, n. 5, p. 1611-1625, MAY 2014.
Citações Web of Science: 16
Resumo

A nonlinear analysis is performed to characterize the effects of a nonsmooth freeplay nonlinearity on the response of an aeroelastic system. This system consists of a plunging and pitching rigid airfoil supported by a linear spring in the plunge degree of freedom and a nonlinear spring in the pitch degree of freedom. The nonsmooth freeplay nonlinearity is associated with the pitch degree of freedom. The aerodynamic loads are modeled using the unsteady formulation. Linear analysis is first performed to determine the coupled damping and frequencies and the associated linear flutter speed. Then, a nonlinear analysis is performed to determine the effects of the size of the freeplay gap on the response of the aeroelastic system. To this end, two different sizes are considered. The results show that, for both considered freeplay gaps, there are two different transitions or sudden jumps in the system's response when varying the freestream velocity (below linear flutter speed) with the appearance and disappearance of quadratic nonlinearity induced by discontinuity. It is demonstrated that these sudden transitions are associated with a tangential contact between the trajectory and the freeplay boundaries (grazing bifurcation). At the first transition, it is demonstrated that increasing the freestream velocity is accompanied by the appearance of a superharmonic frequency of order 2 of the main oscillating frequency. At the second transition, the results show that an increase in the freestream velocity is followed by the disappearance of the superharmonic frequency of order 2 and a return to a simple periodic response (main oscillating frequency). Published by Elsevier B.V. (AU)

Processo FAPESP: 12/14273-6 - Detecção e identificação de não-linearidades em sistemas aeroelásticos
Beneficiário:Rui Marcos Grombone de Vasconcellos
Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado