scholarly journals Finite Element Studies on Free Vibration of Laminated Composite Cylindrical Skew Panels

2014 ◽  
Vol 6 ◽  
pp. 174085
Author(s):  
Srinivasa Chikkol Venkateshappa ◽  
Suresh Yalaburgi Jayadevappa ◽  
Premakumar Wooday Puttiah
Keyword(s):  
Finite Element ◽  
Free Vibration ◽  
Fundamental Frequency ◽  
Composite Laminates ◽  
Orientation Angle ◽  
Laminated Composite ◽  
Skew Angle ◽  
Element Analysis ◽  
Number Of Layers ◽  
Fiber Orientation Angle

This paper presents the finite element studies made on free vibration of isotropic and laminated composite cylindrical skew panels. A finite element analysis is performed using CQUAD4 and CQUAD8 elements of MSC/NASTRAN software. The effects of the panel angle, skew angle, aspect ratio, and length-to-thickness-ratio on fundamental natural frequency of vibration of isotropic cylindrical skew panels are studied. The effects of additional parameters such as fiber orientation angle, numbers of layers (keeping total thickness constant), and laminate stacking sequence on the fundamental frequency of vibration of antisymmetric composite laminates have also been studied. During validation and convergence study, it is found that the CQUAD8 element yields more accurate results than the CQUAD4 element. Hence the CQUAD8 element has been employed for the remaining part of the investigation. The fundamental frequency is found to increase with the panel angle and skew angle. The variation of the fundamental frequency with the number of layers is not appreciable when the number of layers is greater than about 6. It is also seen that the boundary conditions have significant influence on the fundamental frequency.

scholarly journals Finite element studies on free vibration of laminated composite cylindrical skew panels

2014 ◽  
Vol 19 (1) ◽  
pp. 165-180
Author(s):  
C.V. Srinivasa ◽  
Y.J. Suresh ◽  
W.P. Prema Kumar
Keyword(s):  
Finite Element ◽  
Free Vibration ◽  
Fundamental Frequency ◽  
Composite Laminates ◽  
Orientation Angle ◽  
Laminated Composite ◽  
Skew Angle ◽  
Fundamental Frequencies ◽  
Number Of Layers ◽  
Fiber Orientation Angle

Abstract This paper presents the finite element studies on free vibration of isotropic and laminated composite cylindrical skew panels. The analysis is performed using CQUAD4 and CQUAD8 elements of MSC/NASTRAN. The effects of the panel angle, skew angle, aspect ratio and length-to-thickness-ratio on fundamental frequency of isotropic cylindrical skew panels are studied. The effects of additional parameters such as the fiber orientation angle, numbers of layers and stacking sequence on the fundamental frequency of antisymmetric composite laminates are also studied. It is found that the CQUAD8 element yields better results than the CQUAD4 element in the validation and convergence studies. The CQUAD8 element is employed for the remaining part of the studies. The fundamental frequencies are found to increase with the panel angle and skew angle. When the number of layers in the laminate is large, the variation of the fundamental frequency with the number of layers is not appreciable. The boundary conditions are found to have a significant influence on the fundamental frequency

scholarly journals Experimental and Finite Element Studies on Free Vibration of Skew Plates

2014 ◽  
Vol 19 (2) ◽  
pp. 365-377 ◽  
Author(s):  
C.V. Srinivasa ◽  
Y.J. Suresh ◽  
W.P. Prema Kumar
Keyword(s):  
Finite Element ◽  
Aspect Ratio ◽  
Free Vibration ◽  
Composite Laminates ◽  
Natural Frequencies ◽  
Experimental Studies ◽  
Orientation Angle ◽  
Laminated Composite ◽  
Skew Angle ◽  
Experimental Values

Abstract The present paper deals with the experimental studies carried out on free vibration of isotropic and laminated composite skew plates. The natural frequencies were also determined using QUAD8 finite element of MSC/NASTRAN and a comparison was made between the experimental values and the finite element solution. The effects of the skew angle and aspect ratio on the natural frequencies of isotropic skew plates were studied. The effects of the skew angle, aspect ratio, fiber orientation angle and laminate sequence (keeping the number of layers constant) on the natural frequencies of antisymmetric composite laminates were also studied. The experimental values of natural frequencies are in good agreement with the FE solutions. The natural frequencies are found to increase with an increase in the skew angle. The variation of natural frequencies with the aspect ratio is small and negligible both for isotropic and laminated composite skew plates.

scholarly journals Modal Characterization of Sandwich Skew Plates

2021 ◽  
Vol 15 (3) ◽  
pp. 143-153
Author(s):  
Dhotre Pavan Kumar ◽  
Chikkol V. Srinivasa
Keyword(s):  
Finite Element ◽  
Natural Frequencies ◽  
Orientation Angle ◽  
Laminated Composite ◽  
Edge Condition ◽  
Skew Angle ◽  
Composite Sandwich ◽  
Fiber Orientation Angle ◽  
Experimental Values ◽  
Element Free

Abstract The current work focuses on the experimental and finite element free vibration studies of laminated composite sandwich skew plates. The comparison was made between the experimental values obtained by the Fast Fourier transform (FFT) analyzer and a finite element solution obtained from CQUAD8 finite element of The MacNeal-Schwendler Corporation (MSC) / NASA STRucture Analysis (NASTRAN) software. The influence of parameters such as aspect ratio (AR) (a/b), skew angle (α), edge condition, laminate stacking sequence, and fiber orientation angle (θ°) on the natural frequencies of sandwich skew plates was studied. The values obtained by both the finite element and experiment approaches are in good agreement. The natural frequencies increase with an increase in the skew angle for all given ARs.

Finite element studies on buckling of laminated cylindrical skew panels

2014 ◽  
Vol 21 (4) ◽  
pp. 551-558 ◽  
Author(s):  
Chikkol Venkateshappa Srinivasa ◽  
Yalaburgi Jayadevappa Suresh ◽  
Wooday Puttiah Prema Kumar
Keyword(s):  
Finite Element ◽  
Fiber Orientation ◽  
Orientation Angle ◽  
Laminated Composite ◽  
Buckling Load ◽  
Stacking Sequence ◽  
Skew Angle ◽  
Buckling Loads ◽  
Critical Buckling Load ◽  
Fiber Orientation Angle

AbstractThe present paper presents the finite element studies made on critical buckling load of isotropic and laminated composite cylindrical skew panels. Analysis is performed using CQUAD4 and CQUAD8 elements of MSC/NASTRAN. It is found that the CQUAD8 element yields better results compared to the CQUAD4 element in terms of accuracy and convergence. Using the CQUAD8 element, the effects of the panel angle, skew angle, aspect ratio, and length-to-thickness ratio on the critical buckling load of isotropic cylindrical skew panels have been studied. The effects of additional parameters such as fiber orientation angle, numbers of layers (NL), and stacking sequence on the critical buckling load of laminated composite cylindrical skew panels have also been studied. The critical buckling loads are found to increase with the increase in panel angle and skew angle. When the NL in the laminate is large, the variation of the critical buckling load with the NL is not appreciable. The boundary conditions are found to have significant influence on the critical buckling load.

scholarly journals On free vibration of laminated skew sandwich plates: A finite element analysis

2021 ◽  
Vol 10 (1) ◽  
pp. 66-76
Author(s):  
Pavan Kumar Dhotre ◽  
C. V. Srinivasa
Keyword(s):  
Fundamental Frequency ◽  
Orientation Angle ◽  
Face Sheet ◽  
Design Parameters ◽  
Sandwich Plates ◽  
Skew Angle ◽  
Element Analysis ◽  
Fundamental Frequencies ◽  
Number Of Layers ◽  
The Face

Abstract The present work emphasizes the determination of the fundamental frequency of skew sandwich plates with orthotropic core and laminated facings using different design parameters. Finite elements CQUAD4 and CQUAD8 of MSC/NASTRAN are used for obtaining fundamental frequencies, which are validated against available literature results. The influence of the skew angle, the ratio of the length-to total thickness (a/h) of the sandwich plate, and the ratio of the thickness of the core to face sheet (t c /t h ) on the fundamental frequency of skew sandwich plates are studied. Also, the influence of parameters such as the number of layers in the face sheet, laminate sequence, and fiber orientation angle on the fundamental frequency of laminated skew sandwich plates have been studied. It is found that the CQUAD8 element yields better results than the CQUAD4 element in the present study. The fundamental frequencies are found to increase with the increasing skew angle. The variation in fundamental frequency is negligible when the number of layers is large in the face sheet.

Buckling characteristics of cut-out borne composite stiffened hyperbolic paraboloid shell panel

2021 ◽  
pp. 146442072110058
Author(s):  
Sarmila Sahoo
Keyword(s):  
Finite Element ◽  
Orientation Angle ◽  
Buckling Load ◽  
Benchmark Problems ◽  
Hyperbolic Paraboloid ◽  
Element Analysis ◽  
Load Effect ◽  
Global Buckling ◽  
Fiber Orientation Angle ◽  
Shell Panel

The present study investigates buckling characteristics of cut-out borne stiffened hyperbolic paraboloid shell panel made of laminated composites using finite element analysis to evaluate the governing differential equations of global buckling of the structure. The finite element code is validated by solving benchmark problems from literature. Different parametric variations are studied to find the optimum panel buckling load. Laminations, boundary conditions, depth of stiffener and arrangement of stiffeners are found to influence the panel buckling load. Effect of different parameters like cut-out size, shell width to thickness ratio, degree of orthotropy and fiber orientation angle of the composite layers on buckling load are also studied. Parametric and comparative studies are conducted to analyze the buckling strength of composite hyperbolic paraboloid shell panel with cut-out.

Structural Acoustic Problems With Absorbent Layers Within Laminated Composite Enclosures

2006 ◽  
Vol 128 (6) ◽  
pp. 705-712 ◽  
Author(s):  
Arup Guha Niyogi
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Free Vibration ◽  
Laminated Composite ◽  
Transverse Shear Deformation ◽  
Element Formulation ◽  
Structural Damping ◽  
Element Analysis ◽  
First Order ◽  
Acoustic Domain

Studies on coupled structural acoustic problems within laminated composite enclosures are presented. Isoparametric quadratic boundary element formulation for the acoustic domain is coupled to the structural properties of the enclosure through mobility relations obtained from free vibration finite element analysis of the dry enclosure visualized as a folded plate with first order transverse shear deformation and rotary inertia. Velocity amplitudes and forcing frequency is specified over certain parts of the boundary. The rest is interactive boundary. Absorbent layers at the boundary are accommodated through admittance relation. Results show that impact of absorbent layers is frequency dependent while modifying structural damping has a better prospect.

scholarly journals Mode frequency analysis of antisymmetric angle-ply laminated composite stiffened hypar shell with cutout

2019 ◽  
Vol 23 (1) ◽  
pp. 162-171
Author(s):  
Puja Basu Chaudhuri ◽  
Anirban Mitra ◽  
Sarmila Sahoo
Keyword(s):  
Free Vibration ◽  
Natural Frequency ◽  
Frequency Analysis ◽  
Fiber Orientation ◽  
Orientation Angle ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
Mode Frequency ◽  
Thickness Ratio ◽  
Fiber Orientation Angle

Abstract This article deals with finite element method for the analysis of antisymmetric angle-ply laminated composite hypar shells (hyperbolic paraboloid bounded by straight edges) that applies an eight-noded isoparametric shell element and a three-noded beam element to study the mode-frequency analysis of stiffened shell with cutout. Two-, 4-, and 10-layered antisymmetric angle-ply laminations with different lamination angles are considered. Among these, 10-layer antisymmetric angle-ply shells are considered for elaborate study. The shells have different boundary conditions along its four edges. The formulation is based on the first-order shear deformation theory. The reduced method of eigen value solution is chosen for the undamped free vibration analysis. The first five modes of natural frequency are presented. The numerical studies are conducted to determine the effects of width-to-thickness ratio (b/h), degree of orthotropy (E11/E22), and fiber orientation angle (θ) on the nondimensional natural frequency. The results reveal that free vibration behavior mainly depends on the number of boundary constraints rather than other parametric variations such as change in fiber orientation angle and increase in degree of orthotropy and width-to-thickness ratio.

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