Experimental investigation and numerical modelling of domestic scale wind turbine blades

Static testing of two domestic scale wind turbine blades is presented. One of the two blades consists solely of glass-fibre reinforced polypropylene, while the other includes additional carbon-fibre reinforcement in the spar... [ view full abstract ]

Static testing of two domestic scale wind turbine blades is presented. One of the two blades consists solely of glass-fibre reinforced polypropylene, while the other includes additional carbon-fibre reinforcement in the spar caps. Static testing is performed with a Whiffle tree test rig to determine the structural response of the blades. The rig applies the load at eight contact points along the blade to mimic the bending moment profile experienced by a blade in operation. Modal testing was also performed on the two blades and the values of natural frequencies reported. The following objectives were undertaken: (i) evaluate and compare the static test results of the two wind turbine blades, (ii) use the results to validate finite element (FE) models of the blades and (iii) use the validated FE models in a design optimisation study. The FE models are generated using the Python programming language and are based on manufacturing specifications for the blades. The goal of the optimisation study is to improve the stiffness of the glass-fibre blade, without the addition of the more costly carbon-fibre plies. A genetic algorithm is used to determine the optimum section thickness along the length of the blade. The FE models showed close agreement with the experimental results. The result of the optimisation study was a blade 4% heavier than the original glass-fibre blade but with significant improvement in stiffness (30% decrease in tip deflection for the same load). The positive result from this initial design study will enable expansion of the design variables for future analyses.