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 Optimization of Laminated Composite Plates for Maximum Biaxial Buckling Load

2020 ◽  
Vol 36 (2) ◽  
Author(s):  
Pham Dinh Nguyen ◽  
Quang-Viet Vu ◽  
George Papazafeiropoulos ◽  
Hoang Thi Thiem ◽  
Pham Minh Vuong ◽  
...  
Keyword(s):  
Fiber Orientation ◽  
Orientation Angle ◽  
Laminated Composite ◽  
Optimization Procedure ◽  
Composite Plates ◽  
Buckling Load ◽  
Biaxial Compression ◽  
Laminated Composite Plates ◽  
Design Variables ◽  
Fiber Orientation Angle

This paper proposes an optimization procedure for maximization of the biaxial buckling load of laminated composite plates using the gradient-based interior-point optimization algorithm. The fiber orientation angle and the thickness of each lamina are considered as continuous design variables of the problem. The effect of the number of layers, fiber orientation angles, thickness and length to thickness ratios on the buckling load of the laminated composite plates under biaxial compression is investigated. The effectiveness of the optimization procedure in this study is compared with previous works.

Buckling of laminated composite cylindrical skew panels

2015 ◽  
Vol 30 (9) ◽  
pp. 1175-1199
Author(s):  
Srinivasa Venkateshappa Chikkol ◽  
Prema Kumar Puttiah Wooday ◽  
Suresh Jayadevappa Yelaburgi
Keyword(s):  
Finite Element ◽  
Aspect Ratio ◽  
Laminated Composite ◽  
Buckling Load ◽  
Finite Element Solution ◽  
Element Solution ◽  
Skew Angle ◽  
Critical Buckling Load ◽  
Aluminum 7075 ◽  
Experimental Values

Experimental studies were made on isotropic cylindrical skew panels made of Aluminum 7075-T6 and laminated composite cylindrical skew panels under uniaxial compression. The experimental values of the critical buckling load ( Pcr) were determined using five different methods. The values of Pcr were also determined using MSC/Nastran and CQUAD8 finite element. The experimental values of the Pcr obtained by different methods were compared with the finite element solution. The effects of the skew angle and aspect ratio on the critical buckling load of isotropic cylindrical skew panels made of Aluminum 7075-T6 were studied. The effects of the skew angle, aspect ratio, and the laminate stacking sequence on the critical buckling load of laminated composite cylindrical skew panels were also studied. It is found that the method IV (based on a plot of applied load ( P) vs. average axial strain) yields the highest value for Pcr and method III (based on a plot of P vs. square of out-of-plane-deflection) the lowest value for Pcr. The experimental values given by method IV are seen to be closest to the finite element solution, the discrepancy being in the range of 5–23% for laminated composite cylindrical skew panels. For isotropic panels, it is found that the value Pcr initially increases with an increase in the skew angle and later decreases as the skew angle increases beyond 15°. For laminated composite panels, the Pcr value decreases as the aspect ratio increases for all laminate stacking sequences.

The effects of cutouts on buckling behavior of composite plates

2012 ◽  
Vol 19 (3) ◽  
pp. 323-330 ◽  
Author(s):  
Ahmet Erkliğ ◽  
Eyüp Yeter
Keyword(s):  
Fiber Orientation ◽  
Polymer Matrix Composites ◽  
Orientation Angle ◽  
Composite Plates ◽  
Buckling Load ◽  
Matrix Composites ◽  
Element Analysis ◽  
Buckling Loads ◽  
Buckling Behavior ◽  
Fiber Orientation Angle

AbstractCutouts such as circular, rectangular, square, elliptical, and triangular shapes are generally used in composite plates as access ports for mechanical and electrical systems, for damage inspection, to serve as doors and windows, and sometimes to reduce the overall weight of the structure. This paper addresses the effects of different cutouts on the buckling behavior of plates made of polymer matrix composites. To study the effects of cutouts on buckling, loaded edges are taken as fixed and unloaded edges are taken as free. Finite element analysis is also performed to predict the effects of different geometrical cutouts, orientations, and position of cutouts on the buckling behavior. The results show that fiber orientation angle and cutout sizes are the most important parameters on the buckling loads. For all types of cutouts the buckling loads decrease dramatically by increasing the fiber orientation angle. It is observed that minimum buckling load is reached when 45° fiber angle is used, and after this angle critical buckling load begins to increase. Also, it is concluded that while fiber orientation angle is 0°, elliptical cutout has the highest buckling load and while fiber orientation angle is 45°, circular cutout has the highest buckling load.

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.

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.

Experimental and finite element studies on buckling of skew plates under uniaxial compression

2015 ◽  
Vol 22 (3) ◽  
pp. 287-296 ◽  
Author(s):  
Srinivasa Chikkol Venkateshappa ◽  
Suresh Yalaburgi Jayadevappa ◽  
Prema Kumar Wooday Puttiah
Keyword(s):  
Finite Element ◽  
Aspect Ratio ◽  
Uniaxial Compression ◽  
Laminated Composite ◽  
Buckling Load ◽  
Element Solution ◽  
Skew Angle ◽  
Critical Buckling Load ◽  
Aluminum 7075 ◽  
Experimental Values

AbstractExperimental studies were made on isotropic skew plates made of aluminum 7075-T6 and laminated composite skew plates under uniaxial compression with unloaded edges completely free and one loaded edge restrained completely and the other loaded edge restrained except translationally in the direction of loading. Experimental values of the buckling load have been determined using five different methods. The buckling load has also been determined using CQUAD8 finite element of MSC/NASTRAN. Comparison is made between the various experimental values of buckling load and the finite element solution. The effects of the skew angle and the aspect ratio on the critical buckling load of isotropic skew plates made of aluminum 7075-T6 have been studied. The effects of the skew angle, aspect ratio, and the laminate stacking sequence on the critical buckling load of laminated composite skew plates have also been studied. The critical buckling load is found to increase with the increase in the skew angle and decrease with the increase in aspect ratio. Method IV yields the highest value for critical buckling load and Method III the lowest value for critical buckling load. Among the various experimental values, the one given by Method IV is closest to the finite element solution, and the discrepancy between them is less than about 5% in the case of isotropic skew plates and about 10–15% in the case of laminated composite skew plates.

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

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.

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.

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.

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