Free Vibration Behavior of Angle-Ply Laminated Composite Stiffened Plates

2021 ◽  
pp. 2150187
Author(s):  
Leena Sinha ◽  
Amaresh Tripathy ◽  
Amar N. Nayak ◽  
Shishir K. Sahu
Keyword(s):  
Free Vibration ◽  
Numerical Investigation ◽  
Natural Frequencies ◽  
Laminated Composite ◽  
Mode Shapes ◽  
Stiffened Plates ◽  
Vibration Behavior ◽  
Fundamental Frequencies ◽  
Aspect Ratios ◽  
Support Conditions

This paper reports for the first time the experimental investigation on the free vibration characteristics of angle-ply laminated composite stiffened plates along with the numerical investigation. The natural frequencies of these plates are computed experimentally using an FFT analyzer and numerically by employing the finite element method with combination of isoparametric nine nodded plate and three nodded beam elements. Angle-ply laminated stiffened plates are fabricated using woven glass fiber fabrics and epoxy by hand layup technique. The effects of various support conditions; number, orientation and types of stiffeners; aspect ratios of plates and different fiber orientations on the fundamental frequencies of the angle-ply laminated stiffened plates are investigated. These parameters significantly influence the natural frequencies. It is found that there is a very good agreement observed between the fundamental frequencies obtained from both experimental and numerical investigation. Mode shapes are also presented for angle-ply laminated square stiffened plates with three different support conditions to justify the trend of increasing/decreasing of the modal frequency with the addition of stiffeners. It is observed that the enhancement of the frequencies of the angle-ply plates due to addition of stiffeners is influenced significantly by the position of stiffeners and consequently mode shapes. As the research on the free vibration behavior of angle-ply stiffened plates with experimental analysis is very rare, this study can be considered as the benchmark for future research.

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 The Effect of Various Fiber Orientations and Boundary Conditions on Natural Frequencies of Laminated Composite Beam

2018 ◽  
Vol 7 (3.11) ◽  
pp. 67 ◽  
Author(s):  
M Arif Mat Norman ◽  
M Amiruddin Zainuddin ◽  
Jamaluddin Mahmud
Keyword(s):  
Boundary Condition ◽  
Finite Element ◽  
Aspect Ratio ◽  
Free Vibration ◽  
Boundary Conditions ◽  
Composite Beam ◽  
Natural Frequencies ◽  
Laminated Composite ◽  
Mode Shapes ◽  
Laminated Composite Beam

This paper investigates the free vibration characteristics of laminate composite beam for various lamination schemes and under various boundary conditions. A beam model with the aspect ratio (length to thickness) of 25 to 150 made of carbon/ epoxy laminates under free vibration were constructed using a commercially available finite element software (ANSYS). The varied parameters are the lamination schemes (cross ply, angle ply and unidirectional ply) and boundary conditions (Clamp-Free (C-F), Clamp-Clamp (C-C), Clamp-Hanger (C-H), Free-Free (F-F) and Hanger-Hanger (H-H) ). For each case, finite element simulations were performed and the natural frequencies were determined. Mode shapes were also analyzed to observe the beam’s deformation behavior. Results showed that increasing aspect ratio will decrease natural frequencies for the first seven mode shapes. In terms of lamination scheme, the unidirectional ply produced the highest frequency (34.26 Hz), followed by cross ply (34.05 Hz) and angle ply (13.60 Hz) at the aspect ratio of 25. In terms of boundary conditions, the Hanger-Hanger boundary condition produced the highest natural frequency (2272.52  Hz) at the aspect ratio of 25, while Clamped-Free boundary condition produced the lowest frequency (2.28 Hz) at the aspect ratio of 150. In general, it can be concluded that the current study is useful and has contributed significant knowledge to better understand of effect of various fiber orientations and boundary conditions on the natural frequencies of laminated composite beam. 

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

1999 ◽  
Vol 67 (3) ◽  
pp. 568-573 ◽  
Author(s):  
Y. Narita
Keyword(s):  
Free Vibration ◽  
Natural Frequencies ◽  
Numerical Study ◽  
Ritz Method ◽  
Mode Shapes ◽  
Rectangular Plates ◽  
Vibration Behavior ◽  
Edge Conditions ◽  
Important Field ◽  
Anisotropic Rectangular Plates

The free-vibration behavior of rectangular plates constitutes an important field in applied mechanics, and the natural frequencies are known to be primarily affected by the boundary conditions as well as aspect and thickness ratios. Any one of the three classical edge conditions, i.e., free, simply 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. 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 classical edge conditions and is used to numerically verify the numbers. In this numerical study the number of combinations in the free-vibration behavior is determined for some plate models by using the derived formulas. Results are corroborated by counting the numbers of different sets of the natural frequencies that are obtained from the modified Ritz method. [S0021-8936(00)02203-0]

Analytical Piezoelasticity Solution for Natural Frequencies of Levy-Type Piezolaminated Plates

2019 ◽  
Vol 11 (03) ◽  
pp. 1950023 ◽  
Author(s):  
Susanta Behera ◽  
Poonam Kumari
Keyword(s):  
Natural Frequencies ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
Single Layer ◽  
Free Vibration Analysis ◽  
Mode Shapes ◽  
Kantorovich Method ◽  
Extended Kantorovich Method ◽  
Aspect Ratios ◽  
Support Conditions

First time, an analytical solution based on three-dimensional (3D) piezoelasticity is developed for the free vibration analysis of Levy-type piezolaminated plates using 3D extended Kantorovich method (EKM). Extended Hamilton principle (which is extended from elastic to piezoelectric case) is further extended to the dynamic version of mixed form containing contributions from the electrical terms. Multi-term multi-field extended Kantorovich method in conjunction with Fourier series (along [Formula: see text]-direction) is employed to obtain two sets of first-order homogeneous ordinary differential equations (8[Formula: see text] along [Formula: see text]- and [Formula: see text]-axes). A robust algorithm is designed (Fortran Code) to extract the natural frequencies and mode shapes of Levy-type piezolaminated plates. The accuracy and efficacy of this technique are verified thoroughly by comparing it with the existing results in the literature and with the 3D finite element (FE) solutions. Numerical results are presented for single-layer piezoelectric and smart sandwich plates considering five different boundary support conditions, three aspect ratios (length to thickness ratio) and electric open and close circuit conditions. The present results shall be used as a benchmark to assess various two-dimensional (2D) and 3D numerical solutions (e.g., FEM, DQM, etc.).

scholarly journals Free Vibration and Buckling Analysis of the Laminated Composite Beams by Using GDQM

2009 ◽  
Vol 18 (2) ◽  
pp. 096369350901800
Author(s):  
Gökmen Atlıhan ◽  
Ersin Demir ◽  
Zekeriya Girgin ◽  
Hasan Çallıoğlu
Keyword(s):  
Free Vibration ◽  
Natural Frequencies ◽  
Differential Quadrature Method ◽  
Laminated Composite ◽  
Mode Shapes ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Generalized Differential ◽  
Laminated Composite Beam ◽  
Laminated Composite Beams

In this study, effects of stacking sequences of composite laminated beams on natural frequencies and buckling behaviour have been analyzed by Generalized Differential Quadrature Method (GDQM) and Finite Element Method (FEM). Mode shapes were also investigated for one mode of buckling and three modes of free vibration analyses. In addition, variations of mode shapes for different boundary conditions were presented in details. Numerical results show that the effective stiffness of the laminated composite beam can be altered through an adjustment in the stacking sequence. Thus, such an adjustment in stacking sequences allows operations in desired natural frequencies and load carrying capacity without changing its geometry drastically or without changing its weight.

Free vibration analysis of industry-driven woven fiber laminated carbon/epoxy composite beams by experimental and numerical approach

2021 ◽  
Vol 29 (9_suppl) ◽  
pp. S1371-S1385
Author(s):  
Priyadarshi Das ◽  
Shishir K Sahu
Keyword(s):  
Free Vibration ◽  
Modal Analysis ◽  
Natural Frequencies ◽  
Epoxy Composite ◽  
Research Work ◽  
Laminated Composite ◽  
Composite Beams ◽  
Beam Model ◽  
Aspect Ratios ◽  
Laminated Composite Beams

The free vibration study of industry-driven woven fibre laminated carbon/epoxy composite beam is addressed through experimental and numerical modal analysis in the present research work. The experimental modal analysis is performed using the vibration Fast Fourier Transform (FFT) analyser and the natural frequencies are realized in the PULSE environment. A linear beam model is simulated in ABAQUS finite element (FE) software, adopting a solid deformable 8-nodded element with five degrees of freedom (DOF) per node from the ABAQUS library for numerical computation of natural frequencies. A satisfactory agreement is achieved between the experimental and numerical results. The effects of ply-orientation, number of plies, lamination scheme and aspect ratios with different boundary conditions on the natural frequencies are studied. The results confirmed that the predicted vibration characteristics of laminated composite beams are sensitive to the adopted parameters for the investigation. The present study will help to understand the dynamic behaviour for laminated composite beams and serve as an experimental benchmark result within the frequency domain.

Wave characteristics of nonsymmetric cross-ply laminated composite beams

2021 ◽  
pp. 146442072097755
Author(s):  
Richard Bachoo
Keyword(s):  
Free Vibration ◽  
Composite Beam ◽  
Power Flow ◽  
Natural Frequencies ◽  
Numerical Models ◽  
Laminated Composite ◽  
Free Vibration Analysis ◽  
Mode Shapes ◽  
Wave Approach ◽  
Laminated Composite Beam

The free vibration characteristics of a nonsymmetric cross-ply laminated composite beam coupled in bending and longitudinal deformation is studied using a wave approach. The effects of shear deformation and rotary inertia are included in the analysis. Exact analytical expressions are derived for the natural frequencies, mode shapes, and the power flow of the propagating waves. The derived expressions are validated using the results from past literature and provide a benchmark for numerical models. The advantages of the wave approach over conventional free vibration analysis methods are highlighted. Specifically, the wave approach is used to derive a simplified expression for the mode count function of the composite beam. Additionally, the wave approach is also used to investigate the power flow and cross-conversion of the propagating wavetypes across various classical boundary conditions. The influence of the number of cross-ply layers on the natural frequencies and power flow are also investigated. The efficacy of the wave analysis is illustrated through several numerical examples.

scholarly journals Performance Evaluation of Free Vibration of Laminated Composite Stiffened Hyperbolic Paraboloid Shell Panel with Cutout

2016 ◽  
Vol 7 ◽  
pp. 1-24 ◽  
Author(s):  
Sarmila Sahoo
Keyword(s):  
Free Vibration ◽  
Laminated Composite ◽  
Shell Element ◽  
Mode Shapes ◽  
Hyperbolic Paraboloid ◽  
Fundamental Frequencies ◽  
Curved Beam Element ◽  
Edge Conditions ◽  
Practical Engineering ◽  
Shell Panel

The paper considers free vibration characteristics of stiffened composite hyperbolic paraboloid shell panel with cutout in terms of natural frequency and mode shapes. A finite element code is developed for the purpose by combining an eight noded curved shell element with a three noded curved beam element. The size of the cutouts and their positions with respect to the shell centre are varied for different edge conditions of cross-ply and angle-ply laminated shells. The effects of these parametric variations on the fundamental frequencies and mode shapes are considered in details to conclude a set of inferences of practical engineering significance.

Free Vibration Analysis of Stiffened Plates by Including the Effect of Inplane Inertia

1982 ◽  
Vol 49 (1) ◽  
pp. 206-212 ◽  
Author(s):  
G. Aksu
Keyword(s):  
Finite Difference ◽  
Free Vibration ◽  
Natural Frequencies ◽  
Variational Principles ◽  
Free Vibration Analysis ◽  
Energy Functional ◽  
Mode Shapes ◽  
Stiffened Plates ◽  
Finite Difference Technique ◽  
Linear Eigenvalue Problem

A method based on the variational principles in conjunction with the finite difference technique is applied to determine the dynamic characteristic of eccentrically stiffened plates. The inplane deformations in both directions of the plate have been considered and the inplane inertia has been included into the analysis. The strain and kinetic energy for the plate and the stiffener are expressed in terms of discrete displacement components using the finite difference method. The energy functional is minimized with respect to discretized displacement components and the natural frequencies and corresponding mode shapes are obtained from the solution of a linear eigenvalue problem. The effect of inplane deformations of the plate and the stiffener and also the effect of inplane inertia on free vibration characteristics of uniaxial and cross-stiffened plates have been examined.

Sign in / Sign up

Export Citation Format

Share Document