Almost all engineering systems experience strength versus weight conflict of some description. In the case of airplane wing, there are two primary requirements which must be considered during the structural design process: high strength and stiffness, and lower weight. Due to the restricted nature of technology in this field, very few design guidelines are available for design improvement of an airplane wing structure to increase its strength-to-weight ratio. The objective of this thesis is to provide guidelines for the improvement of the structural design of a composite unmanned aerial vehicle (UAV) wing with respect to weight, strength and bending stiffness, with Aludra MK-01 as a case study. The finite element method was used for the numerical analysis on the structure. Popular commercial finite element software, ABAQUS CAE, was used to model the wing structure. A detailed modelling technique for composite structure and the attachment between structures was presented in this thesis. The wing finite element model was validated using experimental results. The design improvement process on the wing structures was conducted in several modes. The variables used in the process were spar web length, spar shape and spar thicknesses. UAV wing structural weight, bending stiffness and failure index were used as the main criteria in the design improvement process. The variation of these criteria with changes in selected parameters were then plotted to observe the design trends. At the end of the research, the improved web lengths and thicknesses were obtained, as also the best combination of shapes for the spars. During the design improvement process, the failure index was found to be most sensitive towards the changes in the variable parameters compared to structural weight and bending stiffness. The design improvement guidelines presented in this thesis should facilitate the design and analysis of future UAV composite wing structures.
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