Open AccessFree vibrations of cylindrical laminated shells – introduction to optimal design in divergence and flutter problems
Author(s) -
Aleksander Muc,
Marcin Augustyn
Publication year - 2020
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/744/1/012004
Subject(s) - flutter , aeroelasticity , rayleigh–ritz method , shell (structure) , eigenvalues and eigenvectors , vibration , finite element method , normal mode , structural engineering , divergence (linguistics) , point (geometry) , composite laminates , buckling , mathematics , mathematical analysis , materials science , geometry , aerodynamics , mechanics , engineering , physics , acoustics , composite material , linguistics , philosophy , quantum mechanics
Aeroelastic properties, such as free vibrations of multilayered composite cylindrical shells, are investigated in the present paper. It is well known that the eigenmode (eigenvalue) analysis is a crucial point in the estimations/calculations of the divergence and flutter speeds characterizng dynamic instability. In this study the maximization problem of eigenfrequencies and eigenmodes is discussed, especially from the point of view of stacking sequences of composite panels. A special attention is focused on two types of the shell wall construction: a) angle-ply ±θ and b) symmetrical discrete laminates built of layers oriented at 0°. ±45° 90°. The analytical formulae is derived with the use of the Rayleigh-Ritz method for simply supported cylinders. It allows us to solve the optimum problem easily for angle-ply fibre orientations. For symmetrical laminates with discrete fibre orientations the optimal solutions are searched for using finite element analysis combined with genetic or evolutionary algorithms. The influence of geometrical parameters describing the cylindrical panel is also demonstrated herein.