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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Grazing bifurcation in aeroelastic systems with freeplay nonlinearity

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Author(s):
Vasconcellos, R. [1] ; Abdelkefi, A. [2] ; Hajj, M. R. [2] ; Marques, F. D. [1]
Total Authors: 4
Affiliation:
[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
Total Affiliations: 2
Document type: Journal article
Source: COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION; v. 19, n. 5, p. 1611-1625, MAY 2014.
Web of Science Citations: 16
Abstract

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)

FAPESP's process: 12/14273-6 - Detection and identification of nonlinearities in aeroelastic systems
Grantee:Rui Marcos Grombone de Vasconcellos
Support Opportunities: Scholarships in Brazil - Post-Doctoral