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 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.

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.

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 Discrete Element Analysis of the Strength Anisotropy of Fiber-Reinforced Sands Subjected to Direct Shear Load

2020 ◽  
Vol 10 (11) ◽  
pp. 3693
Author(s):  
Linxian Gong ◽  
Lei Nie ◽  
Yan Xu
Keyword(s):  
Fiber Orientation ◽  
Tensile Force ◽  
Orientation Angle ◽  
Discrete Element ◽  
Soil Reinforcement ◽  
Direct Shear ◽  
Strength Anisotropy ◽  
Fiber Reinforced ◽  
Element Analysis ◽  
Fiber Orientation Angle

Soil reinforcement with natural or synthetic fibers enhances its mechanical behavior in various applications. Fiber-reinforced sands (FRS) can be relatively anisotropic because of the fiber self-weight and the compaction technique. However, the microscopic mechanisms underlying the anisotropy are still poorly understood. This study used a discrete element approach to analyze the microscopic mechanisms underlying the strength anisotropy of FRS due to fiber orientation. Analysis of contact networks revealed that the optimum fiber orientation angle is perpendicular to the main direction of strong contact force in direct shear testing. These fibers produced the largest increase in shear zone thickness, normal force around the fiber body, effective contact area, tensile force along fibers, and energy storage/dissipation. This study is valuable for further understanding of the mechanical behaviors of FRS.

Effect of fiber orientation angle on patch repaired composite plates

2021 ◽  
Vol 63 (5) ◽  
pp. 436-441
Author(s):  
Mete Onur Kaman ◽  
Fatih Cetisli
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Fiber Orientation ◽  
Plate Thickness ◽  
Orientation Angle ◽  
Composite Plates ◽  
Intensity Factors ◽  
Adhesive Properties ◽  
Crack Problems ◽  
Fiber Orientation Angle

Abstract Stress intensity factors numerically investigated the Mode I loading of composite plates with an edge crack and repaired with a patch on a single side. The effect of the fiber orientation angle for both composite plate and the patch were analyzed with regard to crack length, adhesive properties, and plate thickness. The stress intensity factors were calculated by using the quarter point element that can be applied to 3D crack problems of homogeneous anisotropic materials.It was observed in this study that the fiber orientation angle affects the stress intensity factors significantly.

Fiber Orientation Angle Optimization for Minimum Stress of Laminated Composite Plates

2014 ◽  
Vol 709 ◽  
pp. 135-138
Author(s):  
Ying Tao Chen ◽  
Song Xiang ◽  
Wei Ping Zhao
Keyword(s):  
Genetic Algorithm ◽  
Fiber Orientation ◽  
Optimization Problem ◽  
Orientation Angle ◽  
Laminated Composite ◽  
Composite Plates ◽  
Laminated Composite Plates ◽  
Load Optimization ◽  
Fiber Orientation Angle ◽  
Minimum Stress

The genetic algorithm is used to minimize the stress of the laminated composite plates by optimizing the fiber orientation angle. The objective function of optimization problem is the minimum stress in center of laminated composite plates under the external load; optimization variables are fiber orientation angle. The results for the optimal fiber orientation angle and the minimum stress of the 2-layer plates and 3-layer plates are presented.

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.

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