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Nawfal Nazar Mohammed Hsaine

Self supported dome roofs used for fuel storage tanks.


Project supervisors

Dr Francis Franklin

Dr Hemantha Yeddu

Project description

Dome roofs are large structures often subject to variable wind, snow and other loading, as well as their own weight. We use a wide variety of structural designs in practice. Finding the optimal arrangement of trusses or girders, along with suitable section properties, is a common subject for structural optimisation studies.

I am investigating self-supported dome roofs for fuel storage tanks. I am adapting, developing and comparing a variety of optimisation techniques.

I have compared various load conditions using detailed fluid and stress analysis in ANSYS. I have analysed results for full and empty storage tanks, with wind and/or snow external loads. From this, I have found that the worst cases are for wind loading alone. Snow loading counters the lift force from the wind. Thus, I use the case of an empty fuel storage tank subject to wind loadings as the basis for the structural optimization.=

To speed up the optimisation, I developed a simplified frame analysis in Matlab. I integrated this with the optimization code. I modelled wind loads in ANSYS for a range of dome radii. I imported this into Matlab. I used different dome designs as case studies: ribbed, Schwedler, Lamella and geodesic.

The principal method used to optimise the frame is Morphing Evolutionary Structural Optimization (MESO). An initial overdesigned frame is iteratively analysed and reduced in overall weight by reducing the sections of key frame members. The frame is progressively weakened without compromising the structural integrity until it is no longer possible to reduce the weight. But there are extra parameters that MESO is not suited to. These include the dome radius and those affecting the overall structure of the dome frame, such as numbers and placements of rings. I have investigated a variety of metaheuristic optimisation techniques: Artificial Bee Colony (ABC), Bees Algorithm (BA), Differential Evolution (DE), Particle Swarm Optimization (PSO) and Simulated Annealing (SA).



Structural optimization. Large-scale structures. Domed roof storage tanks.