Spar Design

Improved modular concept of spar design: replacement of thermosets by thermoplastic composite structures to ensure lightweight, load-optimized design.

Spar Cap and Shear Web

A wind turbine blade is a structural beam where the materials carrying the bending loads are the spar caps.  The spar caps run throughout the full length of the blade and are often integrated into the shell of the blade.  The blade is normally hollow apart from the shear webs.

The spar caps should be separated as far apart as possible to achieve the highest level of bending stiffness.  However, the aerodynamic design of a blade defines the shape of the blade and also the distance between the spar caps.

Shear webs

The spar caps are separated by shear webs.  This the same principle as an I-beam whereby the flanges equal the Spar caps and the web equals the Shear web(s).

The shear webs run from the root and along 80-90% of the blade.