FREE VIBRATION ANALYSIS OF LAMINATED COMPOSITES BY A NINE NODE ISO- PARAMETRIC PLATE BENDING ELEMENT (original) (raw)
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Study of free vibration analysis of laminated composite plates with triangular cutouts
Engineering Solid Mechanics, 2015
Cutouts are commonly used as access port for mechanical and electrical structures. Most of the structures generally work under severe dynamic loading and different constrained conditions during their service life. This may lead to vibration of the structure. Therefore, it is necessary to predict the vibration responses of laminated composite plates with cutouts precisely with less computational cost and good accuracy of these complex structures. A suitable finite element model is proposed and developed based on first order shear deformation theory using ANSYS parametric design language (APDL) code. The model has been discretized using an appropriate eight nodded element (SHELL 281) from the ANSYS element library. The free vibrations are computed using Block-Lanczos algorithm. The convergence study has been done of the developed model and compared with those available published literature. Effects of different geometric parameters (aspect ratio, thickness ratio, boundary conditions, number of layers, angle of lamina geometry of cutout, cutout side to plate side ratio and distance between cutouts) and material properties on the free vibration responses are discussed in detail. The frequency increases with increase in the number of layers, modulus ratio of plate and angle of lamina. The frequency decreases with increase in aspect ratio, thickness ratio, size of cutout and distance between cutouts. The boundary conditions of the plate play an important role in the free vibrations of the plate with cutouts. The Non-dimensional frequencies are higher for fully clamped boundary condition in comparison to other boundary conditions.
This paper represents the laminated plate growing researc to dynamic loading in their working life and vibration affects working life of the structure predict of the free vibratio displacements of each layer are expressed in terms of Layerwise HSDT the thickness. The displacement field of present theory contains nine unknowns, as in the higher order shear deformation finding the analytical solutions. supported cross been obtained by using Layerwise HSDT. It is sh can provide accurate results. comparing it with various available results in the literature. The results show that the present model performs better than all the exist theories. ABSTRACT This paper represents the aminated plate growing researc to dynamic loading in their working life and vibration affects working life of the structure. Layerwise predict of the free vibratio displacements of each layer are expressed in terms of Layerwise HSDT the thickness. The displacement field of present theory contains nine unknowns, as in the higher order shear deformation finding the analytical solutions. supported cross been obtained by using Layerwise HSDT. It is sh can provide accurate results. comparing it with various available results in the literature. The results show that the present model performs better than all the exist heories. This paper represents the aminated plate. As we know that vibration and composite material are two main growing research topics now a days. Almost all the structural components subjected to dynamic loading in their working life and vibration affects working life of the Layerwise Higher Order Shear Deformation Theory (predict of the free vibratio displacements of each layer are expressed in terms of Layerwise HSDT the thickness. The displacement field of present theory contains nine unknowns, as in the higher order shear deformation finding the analytical solutions. supported cross-ply and anti been obtained by using Layerwise HSDT. It is sh can provide accurate results. comparing it with various available results in the literature. The results show that the present model performs better than all the exist IJMET/index.asp This paper represents the investigation As we know that vibration and composite material are two main h topics now a days. Almost all the structural components subjected to dynamic loading in their working life and vibration affects working life of the Higher Order Shear Deformation Theory (predict of the free vibration characteristics of laminated composite plates. displacements of each layer are expressed in terms of Layerwise HSDT the thickness. The displacement field of present theory contains nine unknowns, as in the higher order shear deformation finding the analytical solutions. Non ply and anti-symmetric angle been obtained by using Layerwise HSDT. It is sh can provide accurate results. The accuracy of the present theory is ascertained by comparing it with various available results in the literature. The results show that the present model performs better than all the exist asp 414 investigation on the response of a As we know that vibration and composite material are two main h topics now a days. Almost all the structural components subjected to dynamic loading in their working life and vibration affects working life of the Higher Order Shear Deformation Theory (n characteristics of laminated composite plates. displacements of each layer are expressed in terms of Layerwise HSDT the thickness. The displacement field of present theory contains nine unknowns, as in the higher order shear deformation theory Navier's solution method is used for Non-dimensional fundamental frequencies of simply symmetric angle-ply laminated composite plates have been obtained by using Layerwise HSDT. It is sh The accuracy of the present theory is ascertained by comparing it with various available results in the literature. The results show that the present model performs better than all the exist the response of a As we know that vibration and composite material are two main h topics now a days. Almost all the structural components subjected to dynamic loading in their working life and vibration affects working life of the Higher Order Shear Deformation Theory (n characteristics of laminated composite plates. displacements of each layer are expressed in terms of Layerwise HSDT the thickness. The displacement field of present theory contains nine unknowns, as in theory Navier's solution method is used for dimensional fundamental frequencies of simply-ply laminated composite plates have been obtained by using Layerwise HSDT. It is shown that the present Layerwise HSDT The accuracy of the present theory is ascertained by comparing it with various available results in the literature. The results show that the present model performs better than all the existing higher order shear deformation the response of a symmetric composite As we know that vibration and composite material are two main h topics now a days. Almost all the structural components subjected to dynamic loading in their working life and vibration affects working life of the Higher Order Shear Deformation Theory (HSDT n characteristics of laminated composite plates. displacements of each layer are expressed in terms of Layerwise HSDT the thickness. The displacement field of present theory contains nine unknowns, as in theory Navier's solution method is used for dimensional fundamental frequencies of simply ply laminated composite plates have own that the present Layerwise HSDT The accuracy of the present theory is ascertained by comparing it with various available results in the literature. The results show that the ing higher order shear deformation symmetric composite As we know that vibration and composite material are two main h topics now a days. Almost all the structural components subjected to dynamic loading in their working life and vibration affects working life of the HSDT) is used to n characteristics of laminated composite plates. displacements of each layer are expressed in terms of Layerwise HSDT functions of the thickness. The displacement field of present theory contains nine unknowns, as in theory Navier's solution method is used for dimensional fundamental frequencies of simply ply laminated composite plates have own that the present Layerwise HSDT The accuracy of the present theory is ascertained by comparing it with various available results in the literature. The results show that the ing higher order shear deformation symmetric composite As we know that vibration and composite material are two main h topics now a days. Almost all the structural components subjected to dynamic loading in their working life and vibration affects working life of the is used to The functions of the thickness. The displacement field of present theory contains nine unknowns, as in theory Navier's solution method is used for dimensional fundamental frequencies of simply ply laminated composite plates have own that the present Layerwise HSDT The accuracy of the present theory is ascertained by comparing it with various available results in the literature. The results show that the ing higher order shear deformation
The natural frequencies of composite laminates plate with effect of various plate parameters have been studied using ANSYS5.4 program. Laminate composites are increasing used in various mechanical structures and industrial applications, due to their higher stiffness and higher strength-to-weight ratio. The effects of number of layers, angle of fiber orientation, boundary conditions, width to thickness ratio and laminate arrangement with the natural frequencies of plate having cutout at the center are studied. The non-dimensional fundamental frequency of vibration is found to increase with increase in width to thickness ratio and angle of fiber orientation. The natural frequencies of plate depend on size and shape of the cutout, with increasing values from the plate without cutout because the mass of the plate decrease. The effect of number of layers is found to be insignificant beyond four layers and the laminate arrangement show different results between symmetric and anti-symmetric laminate plate. Some of the results compared with M.K.Pandit et al. [2], that have various size of rectangular cutout at the center, with good agreement results.
Latin American Journal of Solids and Structures, 2017
In this paper, a new higher-order layerwise finite element model, developed earlier by the present authors for the static analysis of laminated composite and sandwich plates, is extended to study the free vibration behavior of multilayer sandwich plates. In the present layerwise model, a first-order displacement field is assumed for the face sheets, whereas a higher-order displacement field is assumed for the core. Thanks for enforcing the continuity of the interlaminar displacement, the number of variables is independent of the number of layers. In order to reduce the computation effort, a simply four-noded C 0 continuous isoparametric element is developed based on the proposed model. In order to study the free vibration, a consistent mass matrix is adopted in the present formulation. Several examples of laminated composite and sandwich plate with different material combinations, aspect ratios, boundary conditions, number of layers, geometry and ply orientations are considered for the analysis. The performance and reliability of the proposed formulation are demonstrated by comparing the author's results with those obtained using the three-dimensional elasticity theory, analytical solutions and other advanced finite element models. From the obtained results, it can be concluded that the proposed finite element model is simple and accurate in solving the free vibration problems of laminated composite and sandwich plates.
Free vibrations of laminated composite plates using layerwise displacement model
2012
In this paper Generalized Layer Wise Plate Theory of Reddy (GLPT) is used to formulate an isoparametric finite element model for free vibration of laminated composite plates. With the assumed displacement field, linear strain displacement relations and linear elastic orthotropic material properties for each lamina, virtual work statement is utilized in order to formulate isoparametric finite element model. The original MATLAB computer program is coded for finite element solution. Some new results using GLPT finite element model for soft core sandwich plate is presented, which may be used as the guideline for their optimal design in the laboratory
Composite Structures, 2021
Composite beams are generally utilized in machinery structures with high-speed velocity, aircraft, and lightweight structures because of their high stiffness-to-weight proportions, a high degree of resistance to corrosion, tailor ability, and fatigue. Crack is one of the most critical damages in composite material as it greatly reduces the stiffness and strength of the member. These damages are a prime cause of increasing the vibration amplitude that leads to catastrophic failures. Structures are frequently exposed to dynamic loads during their administration life. So the assessment of the dynamic properties of cracked composite beams is of considerable technical importance and in this way, the subject of the present investigation. In the present study, changes in natural frequencies of industry-driven woven fiber Glass/Epoxy composite bar with transverse cracks are recorded numerically and experimentally. Finite element method (FEM) is utilized to explore the free vibration of the cracked composite beam. The FE model is created utilizing an eight-noded two-dimensional quadratic isoparametric component with 3 degrees of freedom for each node. The numerical analysis is done through the solution of the beam equations for the Eigenvalues accounting for shear deformation. FE software ANSYS is employed for simulation of free vibration. The experimental tests are done by utilizing a hammer test and the frequency response function (FRF) is shown on FFT analyzer. The numerical outcomes acquired utilizing ANSYS are approved with the trial results. The impacts of fiber orientation, crack depth and positions on the frequencies are investigated about its support in applied fields. The recorded test and numerical results agreed on the significant effects of crack location and depth on the natural frequencies of the laminated beam. The results show that the increase in fiber orientation considerably reduces the natural frequencies of the laminated composite beam.
Recently developed inverse hyperbolic shear deformation theory by the authors is extended to analyze the free vibration response of laminated composite and sandwich plates. Euler-Lagrange equations are derived employing the principle of virtual work for the dynamic problem. A Navier type and finite element solutions are proposed to obtain the free vibration response of laminated composite and sandwich plates. A C 0 -continuous isoparametric biquadratic-quadrilateral serendipity element is used for the finite element solution of generalized higher order shear deformation theory so as to ensure its applicability to general laminates subjected to different combinations of boundary conditions. Higher modes of vibration are obtained for laminated cross-ply and angle-ply plates and efficiency of the theory is ensured by comparing the results with the existing results. It is observed that both analytical and finite element solutions with the present theory are capable for accurate prediction of the free vibration response.
Journal of Sound and Vibration, 2015
The finite element vibration analysis of plates has become one of the classical problems over the past several decades. Different finite element plate models based on classical, standard and improved shear deformable plate theories, three-dimensional elasticity equations or their combinations have been developed. The ability and accuracy of each such model can be established by validating it against analytical models, if it is possible, or other numerical models. In this paper, a comparative study of different plate finite element models used for the free vibration analysis of homogeneous isotropic and anisotropic, composite laminated and sandwich thin and thick plates with different boundary conditions is presented. The aim of the study is to find out the weaknesses and strengths of each model used and to pick out their interchangeability for the finite element calculations. For comparisons, the plate models based on classical and first-order shear deformation theories within the framework of both single-layer and layer-wise concept and three-dimensional theory of elasticity are used. The models are created using the finite element package ABAQUS TM. Natural frequencies obtained by the authors are compared with results known in the literature from different analytical or approximate solutions and, then, the correlation between them is discussed in detail. At the end, conclusions are drawn concerning the utility of each model considered for vibration predictions of plates.
International Journal for Numerical Methods in Engineering, 1989
A C'O finite element formulation of the higher-order theory is used to determine the natural frequencies of isotropic, orthotropic and layered anisotropic composite and sandwich plates. The material properties that are typical of high modulus fibre reinforced composites are used to show the parametric effects ofplate aspect ratio, Icngth-to-thickness ratio, degree of orthotropy, number of layers and lamination angle/scheme. The present theory is based on a higher-order displacement model and the three-dimensional Hooke's laws for plate material. The theory represents a more realistic quadratic variation of the transverse shearing strains and linear variation' of the transverse normal strains through the plate thickness. A special mass matrix diagonalization scheme is adopted which conserves the total mass of the element and includes the effects due to rotary inertia terms. The results.presented should he useful in obtaining better correlation between theory and experiment, and to numerical analysts in vcrifying their results.