Effect of Delamination on Natural Frequencies of E-glass and S-glass Epoxy Composite Plates

2021 ◽  
Author(s):  
P. K. Karsh ◽  
Bindi Thakkar ◽  
R. R. Kumar ◽  
Abhijeet Kumar ◽  
Sudip Dey
Keyword(s):  
Natural Frequencies ◽  
Epoxy Composite ◽  
Orientation Angle ◽  
Laminated Composite ◽  
Composite Plates ◽  
Mode Shapes ◽  
Transverse Shear Deformation ◽  
The Finite Element Method ◽  
Modes Of Failure ◽  
Ply Orientation

The delamination is one of the major modes of failure occurring in the laminated composite due to insufficient bonding between the layers. In this paper, the natural frequencies of delaminated S-glass and E-glass epoxy cantilever composite plates are presented by employing the finite element method (FEM) approach. The rotary inertia and transverse shear deformation are considered in the present study. The effect of parameters such as the location of delamination along the length, across the thickness, the percentage of delamination, and ply-orientation angle on first three natural frequencies of the cantilever plates are presented for S-glass and E-glass epoxy composites. The standard eigenvalue problem is solved to obtain the natural frequencies and corresponding mode shapes. First three mode shape of S-Glass and E-Glass epoxy laminated composites are portrayed corresponding to different ply angle of lamina.

scholarly journals Effects of Elliptical Hole on the Correlation of Natural Frequency with Buckling Load of Basalt Laminates Composite Plates

2020 ◽  
Vol 27 (1) ◽  
pp. 216-225
Author(s):  
Buntheng Chhorn ◽  
WooYoung Jung
Keyword(s):  
Free Vibration ◽  
Natural Frequency ◽  
Natural Frequencies ◽  
Basalt Fiber ◽  
Orientation Angle ◽  
Elliptical Hole ◽  
Composite Plates ◽  
Buckling Load ◽  
Mode Shapes ◽  
Geometric Ratio

AbstractRecently, basalt fiber reinforced polymer (BFRP) is acknowledged as an outstanding material for the strengthening of existing concrete structure, especially it was being used in marine vehicles, aerospace, automotive and nuclear engineering. Most of the structures were subjected to severe dynamic loading during their service life that may induce vibration of the structures. However, free vibration studied on the basalt laminates composite plates with elliptical cut-out and correlation of natural frequency with buckling load has been very limited. Therefore, effects of the elliptical hole on the natural frequency of basalt/epoxy composite plates was performed in this study. Effects of stacking sequence (θ), elliptical hole inclination (ϕ), hole geometric ratio (a/b) and position of the elliptical hole were considered. The numerical modeling of free vibration analysis was based on the mechanical properties of BFRP obtained from the experiment. The natural frequencies as well as mode shapes of basalt laminates composite plates were numerically determined using the commercial program software (ABAQUS). Then, the determination of correlation of natural frequencies with buckling load was carried out. Results showed that elliptical hole inclination and fiber orientation angle induced the inverse proportion between natural frequency and buckling load.

Maximizing the Fundamental Natural Frequency of Triangular Composite Plates

1996 ◽  
Vol 118 (2) ◽  
pp. 141-146 ◽  
Author(s):  
S. Abrate
Keyword(s):  
Natural Frequency ◽  
Material Properties ◽  
Composite Structures ◽  
Natural Frequencies ◽  
Ritz Method ◽  
Laminated Composite ◽  
Composite Plates ◽  
Mode Shapes ◽  
Fundamental Natural Frequency ◽  
Wide Range

While many advances were made in the analysis of composite structures, it is generally recognized that the design of composite structures must be studied further in order to take full advantage of the mechanical properties of these materials. This study is concerned with maximizing the fundamental natural frequency of triangular, symmetrically laminated composite plates. The natural frequencies and mode shapes of composite plates of general triangular planform are determined using the Rayleigh-Ritz method. The plate constitutive equations are written in terms of stiffness invariants and nondimensional lamination parameters. Point supports are introduced in the formulation using the method of Lagrange multipliers. This formulation allows studying the free vibration of a wide range of triangular composite plates with any support condition along the edges and point supports. The boundary conditions are enforced at a number of points along the boundary. The effects of geometry, material properties and lamination on the natural frequencies of the plate are investigated. With this stiffness invariant formulation, the effects of lamination are described by a finite number of parameters regardless of the number of plies in the laminate. We then determine the lay-up that will maximize the fundamental natural frequency of the plate. It is shown that the optimum design is relatively insensitive to the material properties for the commonly used material systems. Results are presented for several cases.

The Research of Structural Parameters on Natural Frequency of Laminated Composite Plates

2013 ◽  
Vol 740 ◽  
pp. 461-464
Author(s):  
Fei Zhao ◽  
Jin Wu Wu
Keyword(s):  
Natural Frequencies ◽  
Structural Parameters ◽  
Orientation Angle ◽  
Laminated Composite ◽  
Composite Plates ◽  
Element Model ◽  
Laminated Composite Plates ◽  
Laminated Composite Plate ◽  
Modulus Ratio ◽  
Depth Ratio

In this paper, natural frequencies of laminated composite plates were studied. The layerwise finite element model is imposed to determine the natural frequencies of laminated composite plates. The effects of panel orientation angle, elastic modulus ratio and width-depth ratio on the natural frequencies of the laminated composite are then discussed. With an example of a sixteen-laying laminated plate, the numerical simulations show that the factor of key structural parameters to the natural frequencies of the laminated composite plate is panel orientation angle and width-depth ratio.

Natural Frequencies and Mode Shapes of Laminated Composite Plates: Experiments and FEA

1996 ◽  
Vol 2 (4) ◽  
pp. 381-414 ◽  
Author(s):  
T.J. Anderson ◽  
A.H. Nayfeh
Keyword(s):  
Natural Frequencies ◽  
Laminated Composite ◽  
Composite Plates ◽  
Test Methods ◽  
Mode Shapes ◽  
Boundary Condi Tions ◽  
Element Analysis ◽  
Condi Tions ◽  
Theoretical Results ◽  
Good Agreement

The natural frequencies and mode shapes of several graphite-epoxy plates were determined using experimental modal analysis and finite-element analysis. The experimental and theoretical results are com pared. The samples tested included four types of layups: ±15°, ±30°, cross-ply, and quasi-isotropic plates. Each plate was tested in three configurations: free-hanging, cantilever, and fixed-fixed for a total of twelve test configurations. The material properties of the plates and the test methods used to obtain them are in cluded. There is a very good agreement between the experimental and theoretical results for the free-hanging and cantilever configurations. The agreement for the fixed-fixed results is poor. This indicates that the clamps for the fixed-fixed configuralion are not ideal and that they introduce some uncertainty in the boundary condi tions. The free-hanging results provide accurate experimental natural frequencies of several composite plates; they can be used to validate future theoretical developments. The fixed-fixed results are used to provide pos sible explanations for the discrepancies between the measured and calculated natural frequencies previously reported in the literature.

scholarly journals Effect of Moment of Inertia of Attached Mass on Natural Frequencies of Cantilevered Symmetrically Laminated Plates

2018 ◽  
Vol 1 (2) ◽  
pp. 35-39
Author(s):  
Kenji Hosokawa
Keyword(s):  
Free Vibration ◽  
Natural Frequencies ◽  
Laminated Composite ◽  
Composite Plates ◽  
Vibration Characteristics ◽  
Laminated Plates ◽  
Moment Of Inertia ◽  
Mode Shapes ◽  
Attached Mass ◽  
Structural Applications

Since composite materials such as laminated composite plates have high specific strength and high structural efficiency, they have been usedin many structural applications. It is therefore very important to make clear the vibration characteristics of the laminated plates for the designand the structural analysis. Especially, the vibration characteristics of the laminated plates with attached mass are essential. However, wecannot find the theoretical or experimental approaches for the free vibration of laminated plates with attached mass. In the present study, theexperimental and numerical approaches are applied to the free vibration of cantilevered symmetrically laminated plates with attached mass.First, by applying the experimental modal analysis technique to the cantilevered symmetrically laminated plates with attached mass, thenatural frequencies and mode shapes of the plates are obtained. Next, the natural frequencies and mode shapes of the cantileveredsymmetrically laminated plates with attached mass are calculated by Finite Element Method (FEM). Finally, from the experimental andnumerical results, the effect of the moment of inertia of the attached mass to the natural frequencies and mode shapes of the cantileveredsymmetrically laminated plates are clarified.

scholarly journals Effects of In-Plane Loading on Vibration of Composite Plates

2012 ◽  
Vol 19 (4) ◽  
pp. 619-634 ◽  
Author(s):  
E. Carrera ◽  
P. Nali ◽  
S. Lecca ◽  
M. Soave
Keyword(s):  
Natural Frequencies ◽  
Single Layer ◽  
Laminated Composite ◽  
Composite Plates ◽  
Hierarchical Approach ◽  
The Finite Element Method ◽  
Laminated Composite Plates ◽  
Governing Equations ◽  
Virtual Displacement ◽  
Combined Loadings

This paper deals with the dynamic analysis of pre-stressed laminated composite plates. Particular emphasis is devoted to the case of in-plane mono-axial, biaxial, shear and combined loadings. Both equivalent single layer and layer-wise plate kinematic description are addressed, according to the hierarchical approach proposed by the Carrera's unified formulation. The different kinematic approaches are compared in order to identify the appropriate modeling for laminated composite plates subjected to combined loadings. The principle of virtual displacement is applied in order to obtain governing equations and the corresponding problem is solved through the finite element method. When possible, assessments/comparisons with exact solutions are proposed. Moreover, the effects of different stacking sequences, boundary conditions, geometries and materials on plate natural frequencies are illustrated.

Minimize the Deflection of Laminated Composite Plates under the External Load Using Fiber Orientation Angle

2014 ◽  
Vol 709 ◽  
pp. 144-147
Author(s):  
Ying Tao Chen ◽  
Song Xiang ◽  
Wei Ping Zhao
Keyword(s):  
Fiber Orientation ◽  
External Load ◽  
Optimization Problem ◽  
Orientation Angle ◽  
Laminated Composite ◽  
Composite Plates ◽  
Laminated Composite Plates ◽  
Load Optimization ◽  
Fiber Orientation Angle ◽  
Optimization Parameters

Optimization of fiber orientation angle is studied to minimize the deflection of the laminated composite plates by the genetic algorithm. The objective function of optimization problem is the minimum deflection of laminated composite plates under the external load; optimization parameters are fiber orientation angle of laminated composite plates. The results for the optimal fiber orientation angle and the minimum deflection of the 4-layer plates are presented to demonstrate the validity of present method.

Natural Frequency of Laminated Composite Plates Using a Sinusoidal Theory

2014 ◽  
Vol 709 ◽  
pp. 148-152
Author(s):  
Guo Qing Zhou ◽  
Ji Wang ◽  
Song Xiang
Keyword(s):  
Differential Equations ◽  
Analytical Method ◽  
Deformation Theory ◽  
Natural Frequencies ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
Composite Plates ◽  
Laminated Composite Plates ◽  
Simply Supported ◽  
Sinusoidal Shear Deformation Theory

Sinusoidal shear deformation theory is presented to analyze the natural frequencies of simply supported laminated composite plates. The governing differential equations based on sinusoidal theory are solved by a Navier-type analytical method. The present results are compared with the available published results which verify the accuracy of sinusoidal theory.

scholarly journals Modal analysis of an iced offshore composite wind turbine blade

2021 ◽  
pp. 0309524X2110116
Author(s):  
Oumnia Lagdani ◽  
Mostapha Tarfaoui ◽  
Mourad Nachtane ◽  
Mourad Trihi ◽  
Houda Laaouidi
Keyword(s):  
Wind Turbine ◽  
Modal Analysis ◽  
Turbine Blade ◽  
Natural Frequencies ◽  
Wind Turbine Blade ◽  
Resonance Phenomenon ◽  
Mode Shapes ◽  
The Finite Element Method ◽  
Numerical Work ◽  
Composite Blades

In the far north, low temperatures and atmospheric icing are a major danger for the safe operation of wind turbines. It can cause several problems in fatigue loads, the balance of the rotor and aerodynamics. With the aim of improving the rigidity of the wind turbine blade, composite materials are currently being used. A numerical work aims to evaluate the effect of ice on composite blades and to determine the most adequate material under icing conditions. Different ice thicknesses are considered in the lower part of the blade. In this paper, modal analysis is performed to obtain the natural frequencies and corresponding mode shapes of the structure. This analysis is elaborated using the finite element method (FEM) computer program through ABAQUS software. The results have laid that the natural frequencies of the blade varied according to the material and thickness of ice and that there is no resonance phenomenon.

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