A wind turbine blade generally has complex structures including several layers of composite materials
with shear webs, making its structure design very challenging. In this paper, a structural optimisation
model for wind turbine composite blades has been developed based on a parametric FEA (finite element
analysis) model and a GA (genetic algorithm) model. The optimisation model minimises the mass of composite
blades with multi-criteria constraints. The number of unidirectional plies, the locations of the spar
cap and the thicknesses of shear webs are taken as design variables. The optimisation model takes
account of five constraints, i.e. stress constraint, deformation constraint, vibration constraint, buckling
constraint, and manufacturing manoeuvrability and continuity of laminate layups constraint. The model
has been applied to the blade structural optimisation of ELECTRA 30 kW wind turbine, which is a novel
VAWT (vertical-axis wind turbine) combining sails and V-shape arm. The mass of the optimised blade is
228 kg, which is 17.4% lower than the initial design, indicating the blade mass can be significantly
reduced by using the present optimisation model. It is demonstrated that the structural optimisation
model presented in this paper is capable of effectively and accurately determining the optimal structural
layups of composite blades.