Rational Reinforcing of the Honeycomb Facets Variable Thickness for Wind Turbine

Abstract

Decreasing of wind turbine blade weight by using honeycomb sandwich collides with strength lack of the honeycomb facets at the high loaded places of the blade under heavy wind load. For providing tensile and compressive strength profiling of the variable thickness facets was made. By using response surface model based on design space the facets rational thickness distribution was performed by using optimization. The condition of evenly distributed stresses at narrow range of values for reinforced facets was used like state variables for optimum designing. By combining finite element analysis and sequential programming the response of the thickness within the process integration framework on criteria the rationalization of the facets thickness was performed. The facets thickness variations are assigned by polynomial of fifth degree to provide small difference of stresses in the facets for blade. The angles of the glass fiber stacking relatively of the blade axis for mass minimization were selected on the similar stress reinforcement condition for outside and inside facets of the honeycomb sandwich. The structure of the reinforcing was built to coincide the principal stresses and strains of the facets to longitudinal and transversal direction of the blade. Calculation results were obtained for glass fiber -epoxy resin composite material having and shown that decreasing total mass of the blade 19% compare to shape optimization.