On free vibration response and mode shapes of arbitrarily laminated rectangular plates

2004 ◽  
Vol 65 (1) ◽  
pp. 13-27 ◽  
Author(s):  
Humayun R.H. Kabir
Keyword(s):  
Free Vibration ◽  
Vibration Response ◽  
Mode Shapes ◽  
Rectangular Plates ◽  
Free Vibration Response

scholarly journals Investigation of Free Vibration Response of E-Glass/Epoxy Delaminated Composite Plates

2012 ◽  
Vol 21 (1) ◽  
pp. 096369351202100 ◽  
Author(s):  
Turan Ercopur ◽  
Binnur Goren Kiral
Keyword(s):  
Free Vibration ◽  
Natural Frequency ◽  
Epoxy Composite ◽  
Free Vibration Analysis ◽  
Composite Plates ◽  
Vibration Response ◽  
Mode Shapes ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Free Vibration Response

This paper deals with the finite element analysis of free vibration response of the delaminated composite plates. Free vibration analysis is performed by using ANSYS commercial software developing parametric input files. Natural frequency values and associated mode shapes of E-glass/epoxy composite delaminated plates are determined. Effects of delamination shape, dimension and location on the natural frequency and associated mode shapes are investigated and for the purpose of the observing the effect of the boundary conditions, cantilever and clamped-pinned delaminated composite plates are taken into consideration. Comparisons with the results in literature verify the validity of the developed models in this study. It is observed that the natural frequency decreases in the existence of the delamination and level of the decrease depends on the dimension, shape and location of the delamination.

FREE VIBRATION RESPONSE OF SHEAR-FLEXIBLE MODERATELY-THICK ORTHOTROPIC CYLINDRICAL SHELLS

2006 ◽  
Vol 06 (01) ◽  
pp. 121-138 ◽  
Author(s):  
Z. I. SAKKA ◽  
J. A. ABDALLA ◽  
H. R. H. KABIR
Keyword(s):  
Finite Element ◽  
Fourier Series ◽  
Analytical Solution ◽  
Free Vibration ◽  
Orthotropic Cylindrical Shell ◽  
Shell Element ◽  
Vibration Response ◽  
Fourier Series Expansion ◽  
Mode Shapes ◽  
Free Vibration Response

The free vibration response of shear-flexible moderately-thick orthotropic cylindrical shell panels, with fixed edges, is investigated using an analytical approach. The governing partial differential equations are developed based on Sander's kinematics and are solved using generalized Navier's with a boundary continuous double Fourier series expansion. The frequencies and mode shapes from the analytical solution for various parametric ratios, including degree of orthotropy (stiffness ratio), radius-to-segment ratio and segment-to-thickness ratio are compared with the finite element solutions that are based on an eight-node 48 degrees of freedom shell element. The rate of convergence of the analytical solution method with respect to the number of Fourier series terms, for various parametric ratios, is presented. The results of the analytical solution are very comparable to that of the finite element solution. It is clear that the presented analytical solution can be used as a benchmark to calibrate and validate numerical and finite element solutions that usually involve approximation to shell theories.

Fluid–Structure Interaction Effects on Free Vibration of Containerships

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Shahrokh Sepehrirahnama ◽  
Dong Xu ◽  
Eng Teo Ong ◽  
Heow Pueh Lee ◽  
Kian-Meng Lim
Keyword(s):  
Free Vibration ◽  
Natural Frequencies ◽  
Hydrodynamic Pressure ◽  
Added Mass ◽  
Vibration Response ◽  
Mode Shapes ◽  
Operation Condition ◽  
Structure Interaction ◽  
The Impact ◽  
Free Vibration Response

The interaction between fluid and structure affects the vibration response of the structure due to the additional hydrodynamic pressure. These effects are accounted for by incorporating the so-called added mass into the vibration equation of the structure. In this paper, a containership was used to study the impact of the added mass on its free vibration response. The natural frequencies of the ship decrease after including the added mass in the vibration analysis. It is shown that the frequency-ascending sequence of the wet mode shapes, for which the added mass is accounted for, may differ from that obtained for the dry state of the ship. Also, the effects of different draft levels on the mode shapes of the ship are reported. These results provide a better insight for designing ships based on their wet-state frequencies and mode shapes, which is the typical operation condition when sailing in the open seas.

A Study on Structural System Identification and Damage Detection for Free Vibration Response Using the Wavelet Transform

2015 ◽  
Vol 752-753 ◽  
pp. 1029-1034
Author(s):  
Asnizah Sahekhaini ◽  
Pauziah Muhamad ◽  
Masayuki Kohiyama ◽  
Aminuddin Abu ◽  
Lee Kee Quen ◽  
...  
Keyword(s):  
Free Vibration ◽  
Damage Detection ◽  
Vibration Response ◽  
Structural System ◽  
Modal Parameter ◽  
Modal Parameter Identification ◽  
Complex Morlet Wavelet ◽  
Structural System Identification ◽  
Free Vibration Response ◽  
Energy Components

This paper presents a wavelet-based method of identification modal parameter and damage detection in a free vibration response. An algorithm for modal parameter identification and damage detection is purposed and complex Morlet wavelet is chosen as an analysis wavelet function. This paper only focuses on identification of natural frequencies of the structural system. The method utilizes both undamaged and damage experiment data of free vibration response of the truss structure system. Wavelet scalogram is utilizes for damage detection. The change of energy components for undamaged and damage structure is investigated from the plot of wavelet scalogram which corresponded to the detection of damage.

Combinations for the Free Vibration Behaviors of Anisotropic Rectangular Plates Under General Edge Conditions

1999 ◽  
Author(s):  
Yoshihiro Narita
Keyword(s):  
Free Vibration ◽  
Structural Design ◽  
Natural Frequencies ◽  
Ritz Method ◽  
Technical Information ◽  
Mode Shapes ◽  
Rectangular Plates ◽  
Plate Models ◽  
Edge Conditions ◽  
Anisotropic Rectangular Plates

Abstract The free vibration behavior of rectangular plates provides important technical information in structural design, and the natural frequencies are primarily affected by the boundary conditions as well as aspect and thickness ratios. One of the three classical edge conditions, i.e., free, simple supported and clamped edges, may be used to model the constraint along an edge of the rectangle. Along the entire boundary with four edges, there exist a wide variety of combinations in the edge conditions, each yielding different natural frequencies and mode shapes. For counting the total number of possible combinations, the present paper introduces the Polya counting theory in combinatorial mathematics, and formulas are derived for counting the exact numbers. A modified Ritz method is then developed to calculate natural frequencies of anisotropic rectangular plates under any combination of the three edge conditions and is used to numerically verify the numbers. In numerical experiments, the number of combinations in the free vibration behaviors is determined for some plate models by using the derived formulas, and are corroborated by counting the numbers of different sets of the natural frequencies that are obtained from the Ritz method.

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