Nonlinear free vibration analysis of sandwich shell structures with a constrained electrorheological fluid layer

2012 ◽  
Vol 21 (7) ◽  
pp. 075035 ◽  
Author(s):  
Farough Mohammadi ◽  
Ramin Sedaghati
Keyword(s):  
Free Vibration ◽  
Vibration Analysis ◽  
Fluid Layer ◽  
Free Vibration Analysis ◽  
Electrorheological Fluid ◽  
Shell Structures ◽  
Sandwich Shell ◽  
Nonlinear Free Vibration

Higher-Order Shell Element for the Static and Free-Vibration Analysis of Sandwich Structures

2018 ◽  
Author(s):  
Erasmo Carrera ◽  
Stefano Valvano ◽  
Matteo Filippi
Keyword(s):  
Finite Element ◽  
Free Vibration ◽  
Vibration Analysis ◽  
Shell Thickness ◽  
Input Parameter ◽  
Single Layer ◽  
Free Vibration Analysis ◽  
Shell Structures ◽  
Sandwich Shell ◽  
Power Functions

An advanced shell finite element with a variable kinematic field based on a new zig-zag power function is proposed for the analysis of sandwich shell structures. The kinematic field is written by using an arbitrary number of continuous piecewise polynomial functions. The polynomial expansion order of a generic subdomain is a combination of zig-zag power functions depending on the shell thickness coordinate. As in the classical layer-wise approach, the shell thickness can be divided into a variable number of mathematical subdomains. The expansion order of each subdomain is an input parameter of the analysis. This feature enables the solution to be locally refined over generic regions of the shell thickness by enriching the kinematic field. The advanced finite shell elements with variable kinematics are formulated in the framework of the Carrera Unified Formulation. The finite element arrays are formulated in terms of fundamental nuclei, which are invariants of the theory approximation order and the modelling technique (Equivalent-Single-Layer, Layer-Wise). In this work, the attention is focused on linear static stress analysis and the free-vibration analysis of sandwich shell structures.

scholarly journals Nonlinear Free Vibration Analysis of Axisymmetric Polar Orthotropic Circular Membranes under the Fixed Boundary Condition

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Zhoulian Zheng ◽  
Jianjun Guo ◽  
Weiju Song ◽  
Xiaoting He ◽  
Faming Lu ◽  
...  
Keyword(s):  
Free Vibration ◽  
Vibration Analysis ◽  
Free Vibration Analysis ◽  
Circular Membrane ◽  
Nonlinear Free Vibration ◽  
Frequency Method ◽  
Initial Displacement ◽  
Small Deflection ◽  
Deflection Theory ◽  
Polar Orthotropic

This paper presents the nonlinear free vibration analysis of axisymmetric polar orthotropic circular membrane, based on the large deflection theory of membrane and the principle of virtual displacement. We have derived the governing equations of nonlinear free vibration of circular membrane and solved them by the Galerkin method and the Bessel function to obtain the generally exact formula of nonlinear vibration frequency of circular membrane with outer edges fixed. The formula could be degraded into the solution from small deflection vibration; thus, its correctness has been verified. Finally, the paper gives the computational examples and comparative analysis with the other solution. The frequency is enlarged with the increase of the initial displacement, and the larger the initial displacement is, the larger the effect on the frequency is, and vice versa. When the initial displacement approaches zero, the result is consistent with that obtained on the basis of the small deflection theory. Results obtained from this paper provide the accurate theory for the measurement of the pretension of polar orthotropic composite materials by frequency method and some theoretical basis for the research of the dynamic response of membrane structure.

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