Spar/Shear Web

A wind blade is a structural beam that throughout its operating life is subjected to considerable lift forces on its aerodynamic profile. Stiffening of the blade is therefore essential to resist bending. Sometimes two strips of reinforcing material are used to provide local stiffening - one on the upwind face and one on the downwind face. However, to provide the essential shear strength these two strips need to be structurally joined by a construction called a shear web.

There are different ways of designing this spar/shear web – either as a girder-structure connected by one or two shear-webs or as a full box-like beam structure. The longer the blade, the higher the performance demands on such load carrying structures. The stiffness of the material in the structural beam is crucial as it prevents the blade from striking the tower when rotating. The structural integrity of the wind blades depends on the combination of composites used to build the load carrying structures and the highest quality materials are therefore required for such applications. Hexcel has an optimized range of prepregs and other fiber-reinforced composites for spar/shear web construction, including UD reinforced carbon and glass materials, as well as our new range of SuperCap™ products.