The Wind Energy Technology Department at Sandia National Laboratories (SNL) focuses on producing innovations in wind turbine blade technology to enable the development of longer blades that are lighter, more structurally and aerodynamically efficient, and impart reduced loads to the system. A large part of the effort is to characterise the properties of relevant composite materials built with typical manufacturing processes. This paper provides an overview of recent studies of composite laminates for wind turbine blade construction and summaries test results for three prototype blades that incorporate a variety of material-related innovations.
One of the primary goals for blade research is to keep blade weight growth under control. For cantilevered beams, which turbine blades can be approximated as, root loads caused by gravity approximately scale as the cube of the blade length. As turbines continue to grow, these gravity loads become more of a constraining design factor. That is, unless the increase in blade weights can be contained by more efficient design methodology. Figure 2 shows blade weight growth trends as a function of rotor radius from commercial data and WindPACT preliminary designs (3). Here we can observe trend lines of older commercial designs, newer commercial designs, and designs that have come out of the DOE-sponsored WindPACT studies (4) that incorporate new concepts. The figure shows that it is possible to lower the growth rate from an exponent of 3.0 to as low as about 2.5.
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