Faculty of Engineering and Built Environment
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Item A comparative analysis of evolutionary algorithms in the design of laminated composite structures(De Gruyter, 2015) Tabakov, Pavel Y.; Moyo, SibusisoAbstract: The increased use of composite materials and structures in many engineering applications led to the need for a more accurate analysis and design optimi-zation. While methods of stress-strain analysis devel-oped faster, optimization techniques have been lagging behind. As a result, many designed structures do not ful-fill their full potential. The present study demonstrates the major achievements in recent years in an application of evolutionary algorithms to the design optimization of fiber-reinforced laminated composite structures. Such structures are of much interest due to high structural design sensitivity to fiber orientations as well as complex multidimensional discrete optimization problems. Using an anisotropic multilayered cylindrical pressure vessel and an exact elasticity solution as an example, we show how the optimum, or near–optimum, solution can be found in a more efficient way.Item A technique for stiffness improvement by optimization of fiber steering in composite plates(Springer, 2010) Tabakov, Pavel Y.; Walker, MarkA methodology for stiffness improvement by optimal orientation of fibers placed using fiber steering techniques of composite plates has been developed and is described here. A genetic algorithm is employed to determine the optimal orientation of the tow fibers and, in addition, once the plate has been divided up into cells in order to apply the technique, the orientation gradient between adjacent cells is capped. The finite element method (FEM) is used to determine the fitness of each design candidate. The approach developed also differs from existing ones by having a more sophisticated chromosome string. By relying on the algorithm for the calculation of the fiber orientation in a specific cell, a relatively short and rapid convergence string is assembled. The numerical results obtained show a significant improvement in stiffness when the fiber orientation angle is allowed to vary spatially throughout the ply.Item Lay-up optimization of multilayered anisotropic cylinders based on a 3-D elasticity solution(Elsevier, 2006) Tabakov, Pavel Y.; Summers, E. B.Exact elasticity solutions are obtained using the stress function approach, where the radial, circumferential and shear stresses are determined, taking into account the closed ends of the cylindrical shell. The system of the governing algebraic equations is derived to accurately analyse a multilayered pressure vessel with an arbitrary number of layers and any thickness. The approach used is straight-forward compared to other three-dimensional solutions found in the literature. The design of multilayered composite pressure vessels is accomplished using the genetic algorithm and subject to the Tsai–Wu failure criterion. The genetic algorithm is optimized to serve this particular problem