Panel Flutter of a Variable-Thickness Composite Shell
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PANEL FLUTTER OF A VARIABLE-THICKNESS COMPOSITE SHELL
V. N. Bakulin,1,2* M. A. Konopelchev,2 and A. Ya. Nedbai3
Keywords: аeroelastic stability, composite shell, variable thickness Systems of equations are obtained to study the onset of panel flutter of a composite shell with a linearly varying thickness. Using a model developed, the critical flow-over speed, corresponding to the onset of flutter, as a function of thickness difference between the left and right ends of the shell is calculated for various values of the axial compressive force and shell length with and without considering its structural damping. The discrepancy between the critical flow-over speed calculated for the shell and a shell with the corresponding integrally average constant thickness is determined.
Introduction. Composite shells find wide application in space technology and aircraft production [1]. An analysis of efficiency of the use of multiwall and sandwich shells in rocket technology is carried out in [2]. During the motion of flying devices in dense atmosphere layers, the panel flutter can arise in their shells flown over by air streams. The interaction of shells with gas streams is investigated in [3-5] and the dynamic behavior of the shells — in [6-8]. The topological optimization (removal of material from the unstressed zones of a part) in designing elements of flying devices allows one to create structures with a minimal weight and a high material utilization factor. This is especially topical for structures of composites on the basis of fabrics, which allows their machining without disrupting the overall integrity of the materials. For the shells of revolution, such an optimization results in structures with a variable thickness.
Russian Academy of Sciences, Institute of Applied Mechanics, Moscow, Russia Moscow Aviation Institute (National Research University), Russia 3 Corporation “The Moscow Institute of Heat Engineering,” Moscow, Russia * Corresponding author; e-mail: [email protected] 1 2
Translated from Mekhanika Kompozitnykh Materialov, Vol. 56, No. 5, pp. 919-932, September-October, 2020. Original article submitted August 7, 2019; revision submitted May 20, 2020. 0191-5665/20/5605-0629 © 2020 Springer Science+Business Media, LLC
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In [9-11], sandwich shells are considered and in [12, 13] — multilayered shells of variable thickness. Work [14] is devoted to the stability of plates of variable thickness, but [15-18] — to the vibration of shells with a variable thickness. In [19, 20], shells with a piecewise-constant thickness variation are considered. The dynamic stability of composite shells are studied in [20-24], and the supersonic flutter of plates and shells — in [21, 25-29]. From an analysis of scientific publications, including the most complete review of works presented in [5], it follows that the flutter of variable-thickness shells has not been investigated fully enough. Mathematical model. In the present work, the aeroelastic stability (panel flutter) of a thin orthotropic cylindrical shell hinge-supported at
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