Experimental and numerical flutter analysis of a folding fin with multiple asymmetric free-plays  

作　　者：Chenyu LIU Chao AN Changchuan XIE Xin ZHANG Lan YANG 

机构地区：[1]School of Aeronautic Science and Engineering,Beihang University,Beijing 100191,China [2]Beijing Institute of Electronic System Engineering,Beijing 100854,China [3]Beijing Institute of Astronautical Systems Engineering,Beijing 100076,China

出　　处：《Chinese Journal of Aeronautics》2024年第5期332-348,共17页中国航空学报（英文版）

基　　金：This study was supported by the National Natural Science Foundation of China(No.12102027).

摘　　要：Experimental folding fin models with an adjustable free-play are tested in a wind tunnel.The fin structure is modeled using the free-interface component mode synthesis method,and its free-play is modeled as four independent nonlinear springs with asymmetric stiffness.A nonplanar unsteady vortex-lattice method considering compressibility is employed to address nonlinear deformation and high subsonic flow.Surface spline interpolation is improved through projection and partition.The aeroelastic characteristics of folding fins with different free-play magnitudes,initial conditions and elastic-axis positions are analyzed using an established time-marching method because of its relatively small computation scale and high precision.The results show good consistency among the presented method,the wind tunnel test and the harmonic balance method.There is a negative correlation between the critical speed of divergent motion and the ratio of the initial condition to the free-play magnitude.If either the free-play magnitude or the initial condition is extreme(tiny or vast),the system nonlinearity degenerates to linearity.Generally,the flutter prevention design of a linear model can be applied to a nonlinear model,such as moving the elastic-axis position aftward.The presented fin configuration exhibits an unstable limit cycle oscillation because the orders of coupled flutter modes do not change with variations in equivalent linear stiffness.

关 键 词：Free-play Limit cycle oscillation FLUTTER Component mode synthesis Vortex-lattice method 

分 类 号：V211.47[航空宇航科学与技术—航空宇航推进理论与工程]