Effects of composite fiber orientation on wind turbine blade buckling resistance

Abstract

This paper utilized the inherent directional properties of composite materials to increase the critical buckling load of a 70 m carbon/glass hybrid wind turbine blade. The effect of changing the fiber orientations of the less stiff, off-axis glass fiber plies (referred to as stability plies in this paper) was studied via nonlinear finite element buckling simulations. The orientation of the stability plies was found to influence the onset of the Brazier effect, which further influenced blade stability and buckling failure location. Although both blade weight and laminate thickness remained constant, an increase in critical buckling load of 8% was achieved with a negligible change in bending stiffness. The more stable blade allowed for removal of material leading to a decrease in maximum laminate thickness and a drop in blade mass of 3.3%. Modifications to the ply stacking sequence and carbon fiber usage were also considered and were found to affect the buckling load but not necessarily the optimum fiber orientation of the stability plies.

Materials, Innovations and Future Research Opportunities on Wind Turbine Blades—Insight Review

“…This had a negligible effect on bending stiffness and the first flap wise natural frequency. Reductions in torsional stiffness were observed for the optimal fiber orientations but were found to have negligible impacts on the flap‐wise loads and CBLs .…”

“…In addition, carbon fiber reinforced composites are used in the large scale [24,26,27,56,57]. In 2014, it was analyzed that an orientation of carbon fibers has a great effect of buckling resistance of wind turbine [58]. Even though the hybrid material structures is expensive, it has the following advantages; Since the usage of carbon fiber can be reduced by using hybrid reinforcements (E-glass/carbon, E-glass/aramid, etc.).…”

“…The study has been conducted to understand the buckling behavior under the load. The result from these EWM buckling study has given a table at [58]. A maximum increase of 8% in CBL was achieved by changing the orientation of the stability lies from AE45 as specified in the reference blade to AE70 .…”

A framework for isogeometric‐analysis‐based optimization of wind turbine blade structures

“…In particular, it has been suggested that blade buckling, especially with regard to nonlinear effects, is of concern for longer blades. ()…”

“…In particular, it has been suggested that blade buckling, especially with regard to nonlinear effects, is of concern for longer blades. [3][4][5][6][7] Wind turbine blade design typically relies heavily on computationally efficient, reduced-order aerodynamic and structural models, especially in the early stages of blade design. This is a sensible approach given a vast design space, the large number of design iterations typically performed, and the ample accuracy of many reduced-order models.…”