Faculty of Engineering and Built Environment
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Item A computational methodology to select the optimal material combination in laminated composite pressure vessels(2012-12) Tabakov, Pavel Y.; Walker, MarkA methodology to select the best material combination and optimally design laminated composite pres-sure vessels is described. The objective of the optimization is to maximize the critical internal pressure subject to cost constraints. Exact elasticity solutions are obtained using the stress function approach, where the stresses are determined taking into account the closed ends of the cylindrical shell. The approach used here allows us to analyze accurately multilayered pressure vessels with an arbitrary number of orthotropic layers of any thickness and a combination of different materials. The design optimization of the pressure vessel is accomplished using the Big Bang–Big Crunch algorithm,subject to the Tsai-Hill failure criterion.Item Design optimization of anisotropic pressure vessels with manufacturing uncertainties accounted for(Elsevier, 2013-04) Tabakov, Pavel Y.; Walker, MarkAccurate optimal design solutions for most engineering structures present considerable difficulties due to the complexity and multi-modality of the functional design space. The situation is made even more complex when potential manufacturing tolerances must be accounted for in the optimizing process. The present study provides an original in-depth analysis of the problem and then a new technique for determining the optimal design of engineering structures, with manufacturing tolerances accounted for, is proposed and demonstrated. The numerical examples used to demonstrate the technique involve the design optimization of anisotropic fibre-reinforced laminated pressure vessels. It is assumed that the probability of any tolerance value occurring within the tolerance band, compared with any other, is equal, and thus it is a worst-case scenario approach. A genetic algorithm with fitness sharing, including a micro-genetic algorithm, has been found to be very suitable to use, and implemented in the technique.Item A technique for optimally designing fibre-reinforced laminated plates with manufacturing uncertainties for maximum buckling strength(Taylor & Francis, 2005) Walker, Mark; Hamilton, Ryan JasonThis article describes a procedure to design symmetrically laminated plates for maximum buckling load with manufacturing uncertainty in the ply angle, which is the design variable. It is assumed that the probability of any tolerance value occurring within the tolerance band, compared with any other, is equal. The methodology is flexible enough to allow any appropriate problem formulation and search algorithm to be substituted. Three different tolerance scenarios are used for the purposes of illustrating the methodology, and plates with varying aspect ratios and loading ratios are optimally designed and compared.