scholarly journals Effect of material anisotropy on buckling load for laminated composite decks plates

2019 ◽  
Author(s):  
Osama Mohammed Elmardi Suleiman
Keyword(s):  
Laminated Composite ◽  
Buckling Load ◽  
Material Anisotropy

scholarly journals Experimental and Numerical Buckling Analyses of Laminated Composite Plates under Temperature Effects

2010 ◽  
Vol 19 (4) ◽  
pp. 096369351001900 ◽  
Author(s):  
Emin Ergun
Keyword(s):  
Composite Plate ◽  
Numerical Solutions ◽  
Laminated Composite ◽  
Composite Plates ◽  
Buckling Load ◽  
Fibre Reinforcement ◽  
Stacking Sequence ◽  
Laminated Composite Plates ◽  
Different Temperatures ◽  
Good Agreement

The aim of this study is to investigate, experimentally and numerically, the change of critical buckling load in composite plates with different ply numbers, orientation angles, stacking sequences and boundary conditions as a function of temperature. Buckling specimens have been removed from the composite plate with glass-fibre reinforcement at [0°]i and [45°]i (i= number of ply). First, the mechanical properties of the composite material were determined at different temperatures, and after that, buckling experiments were done for those temperatures. Then, numerical solutions were obtained by modelling the specimens used in the experiment in the Ansys10 finite elements package software. The experimental and numerical results are in very good agreement with each other. It was found that the values of the buckling load at [0°] on the composite plates are higher than those of other angles. Besides, symmetrical and anti-symmetrical conditions were examined to see the effect of the stacking sequence on buckling and only numerical solutions were obtained. It is seen that the buckling load reaches the highest value when it is symmetrical in the cross-ply stacking sequence and it is anti-symmetrical in the angle-ply stacking sequence.

Flutter of Perforated Metallic Plates Repaired with Cross-Ply Composite Patches

2009 ◽  
Vol 417-418 ◽  
pp. 709-712
Author(s):  
Ali Amin Yazdi ◽  
Jalil Rezaeepazhand
Keyword(s):  
Laminated Composite ◽  
Material Anisotropy ◽  
Perforated Plates ◽  
Closed Form Solutions ◽  
Finite Element Software ◽  
Composite Patch ◽  
Numerical Studies ◽  
Flutter Analysis ◽  
Flutter Boundary ◽  
Metallic Plates

This study investigates the application of laminated composite patches for enhancement of flutter behavior of perforated metallic plates repaired with an external composite patch. Due to material anisotropy and discontinuity in geometry involved in flutter analysis of repaired plates, closed form solutions are practically unobtainable. Numerical studies using commercial finite element software were conducted to investigate the effects of variation in lamination parameters on the flutter boundary of perforated plates repaired with cross-ply composite patches. Both ply-level and sub-laminate level configurations are investigated. Presented results illustrate that flutter boundaries of perforated plates can be changed by choosing proper stacking sequence for composite patches.

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.

scholarly journals The Prediction of Buckling Load of Laminated Composite Hat-Stiffened Panels Under Compressive Loading by Using of Neural Networks

2018 ◽  
Vol 12 (1) ◽  
pp. 468-480 ◽  
Author(s):  
Shashi Kumar ◽  
Rajesh Kumar ◽  
Sasankasekhar Mandal ◽  
Atul K. Rahul
Keyword(s):  
Neural Network ◽  
Finite Element ◽  
Network Architecture ◽  
Laminated Composite ◽  
Buckling Load ◽  
Stiffened Panel ◽  
Stiffness Ratio ◽  
Data Set ◽  
Stiffened Panels ◽  
Structural Problems

Background:Stiffened panels are being used as a lightweight structure in aerospace, marine engineering and retrofitting of building and bridge structure. In this paper, two efficient analytical computational tools, namely, Finite Element Analysis (FEA) and Artificial Neural Network (ANN) are used to analyze and compare the results of the laminated composite 750-hat-stiffened panels.Objective:Finite Element (FE) is an efficient and versatile method for the analysis of a complex problem. FE models have been used to generate data set of four different parameters. The four parameters are extensional stiffness ratio of skin in the longitudinal direction to the transverse direction, orthotropy ratio of the panel, the ratio of twisting stiffness to transverse flexural stiffness and smeared extensional stiffness ratio of stiffeners to that of the plate.Results and Conclusion:For training of ANN, multilayer feedforward back-propagation has been used as a network function with two-hidden layers in the neural network. The good network architecture is achieved after several iterations to predict the buckling load of the stiffened panel. ANN prediction for unknown new data set is in good agreement with FEA results of different cases, which show that ANN tool can be used for the design of complex structural problems in civil engineering and optimization of the laminated composite stiffened panel.

Structural Optimization of Laminated Composite Plates for Maximum Buckling Load Capacity Using Genetic Algorithm

2007 ◽  
Vol 348-349 ◽  
pp. 725-728 ◽  
Author(s):  
Omer Soykasap ◽  
Şükrü Karakaya
Keyword(s):  
Genetic Algorithm ◽  
Structural Optimization ◽  
Load Capacity ◽  
Laminated Composite ◽  
Global Solutions ◽  
Composite Plates ◽  
Buckling Load ◽  
Laminated Composite Plates ◽  
Static Loads ◽  
Aspect Ratios

In this study, the structural optimization of laminated composite plates for maximum buckling load capacity is performed by using genetic algorithm. The composite plate under consideration is a 64-ply laminate made of graphite/epoxy, is simply supported on four sides, and subject to in-plane compressive static loads. The critical buckling loads are determined for several load cases and different plate aspect ratios using 2-ply stacks of 02, ±45, 902. The problem has multiple global solutions, the results of which are compared with previously published results.

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.

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