Nonlinearities of an Aircraft Piccolo Tube: Identification and Modeling
Piccolo tubes are parts of aircraft wings anti-icing system and consist of titanium pipes inserted into the internal structure of the slat. Due to differential thermal expansion, clearances between the tube and its support are unavoidable and cause the overall system to exhibit highly nonlinear behavior, resulting from impacts and friction. This paper addresses the identification and modeling of the nonlinearities present in the slat-Piccolo tube connection. The complete identification procedure, from nonlinearity detection and characterization to parameter estimation, is carried out based upon sine-sweep measurements. The use of several techniques, such as the acceleration surface method, enables to understand the complex dynamics of the Piccolo tube and build a reliable model of its nonlinearities. In particular, the parameters of nonsmooth nonlinear stiffness and damping mechanisms are estimated. The nonlinear model is finally validated on standard qualification tests for airborne equipments.
KeywordsNonlinear system identification Finite element model updating Finite element model upgrading Aircraft anti-icing system Piccolo tube Acceleration surface method (ASM) Vibroimpact Contact force model
The authors T. Dossogne and J.P. Noël are Research Fellow (FRIA fellowship) and Postdoctoral Researcher, respectively, of the Fonds de la Recherche Scientifique – FNRS which is gratefully acknowledged.
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