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

2010 ◽  
Vol 19 (4) ◽  
pp. 096369351001900 ◽  
Author(s):  
Emin Ergun

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.

Author(s):  
C. W. Kim ◽  
J. S. Lee

An optimization procedure using a genetic algorithm (GA) is proposed to determine the optimal stacking sequence of laminated composite plates for the maximum buckling load under several different loadings, such as uniaxial compression, shear, biaxial compression, and the combination of shear and biaxial loadings. A series of optimal design is conducted for composite laminates having different aspect ratios, load conditions, and number of plies. Critical buckling load is taken as fitness function and fibre orientations are taken as design variables. A performance index is introduced to represent the effectiveness of optimal design with respect to worst case design. Then, for uniaxial compression loading, postbuckling behaviour is analysed numerically for the optimally designed composite plates as well as the worst case design composite plate. It shows the outstanding postbuckling performance of one of the optimally designed composite plates against the worst case design composite plate. Also, a GA finds the global solution without requiring auxiliary information such as derivatives of the objective function.


Author(s):  
Pham Dinh Nguyen ◽  
Quang-Viet Vu ◽  
George Papazafeiropoulos ◽  
Hoang Thi Thiem ◽  
Pham Minh Vuong ◽  
...  

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.


2007 ◽  
Vol 348-349 ◽  
pp. 725-728 ◽  
Author(s):  
Omer Soykasap ◽  
Şükrü Karakaya

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.


2012 ◽  
Vol 248 ◽  
pp. 379-383
Author(s):  
Rasoul Khandan ◽  
Philip Sewell ◽  
Siamak Noroozi ◽  
Mohammad Reza Ramazani

Considering the non-linearity, complexity and anisotropy of constitutive equations in composite materials, numerical methods are essential to evaluate the behaviour of this material. The finite element method (FEM) is a powerful computational technique for the solution of differential and integral equations that arise in various fields of engineering and applied science such as composite materials. Here, an FEM tool is designed to analyse non-linearity in the behaviour of composites caused by the effect of transverse shear and twist in laminated composite plates. The tool is established by using FEM for composites in ABAQUS combined with programming in Python to run the tests for all possible fibre orientations in laminated composite plates. It is shown that the tool has the ability to design laminated composite plates by considering the effect of transverse shear and the tool’s output provides results for all different fibre orientations. It is demonstrated that there is good agreement between numerical results obtained from this tool and experimental results. The advantages of the tool give designers the opportunity to use this tool for wide range of products.


2013 ◽  
Vol 853 ◽  
pp. 686-692
Author(s):  
Gong Dong Wang ◽  
Jun Wang ◽  
Hao Chen

An improved Memetic algorithm is applied in this article. Mathematical model is proposed to optimize the laminate strength. The composites laminate strength optimization system with local operator library and rule operator library has been developed by the object-oriented programming with C++. The local operator has contributed to increase the convergence rate and the rule operators have contributed to implement practical design aspects in optimization of laminated composite plates. A numerical example demonstrates the validity of optimization model and practical applicability of the improved Memetic algorithm; hence, exhibiting the improvement of the method in tackling the stacking sequence.


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