Abstract: A polygonal composite structure is formed using a filament winding process. The composite structure formed on a mandrel having a longitudinal axis, comprises an inner structural layer, an outer structural layer, and a plurality of corner pieces. The inner and outer structural layers are formed by winding a fibre reinforcement material, having a resin applied thereon, about a mandrel. The fibre reinforcement material is oriented at a winding angle relative to the longitudinal axis. Each of the plurality of corner pieces is located at each corner of the polygonal structure between the inner structural layer and the outer structural layer. Each of the plurality of corner pieces is oriented lengthwise along the length of the structure. The number of corner pieces is equivalent to the number of sides of the structure.