The mini-substructure test is a simplified, less costly approach to substructure testing that provides efficient comparisons of resins, fabrics, and geometric details in structural context. The coupons represent more realistic internal (infused) blade structural detail areas than standard laminate tests.
Since 1989, Sandia has partnered with Montana State University to test and report key data and trends of fiber-reinforced polymers (composites) and other materials used to construct wind-turbine blades.
The average wind turbine installed in 1989 had a power rating of 0.225 MW and a rotor diameter of 27 m. By the end of 2012, industry averages had increased to a 1.95 MW turbine and a 93.5 m rotor diam. This growth in blade length has put increasingly difficult technical and economic demands on blade designers, requiring a constantly improving understanding of composite material behavior in realistic wind applications.
The MSU-Sandia research team collected the results of over 12,000 tests into a publicly available database in addition to technical papers explaining key trends to meet this critical industry need. Recent work has focused on a variety of industry-relevant areas
- investigating the phenomena of creep in composite fatigue loading,
- testing new materials such as urethane resins and aligned strand material forms that may have manufacturing and cost advantages,
- studying adhesive fracture to better understand the cause and progression of damage in adhesive joints,
- developing test methods and testing core material strength and fatigue, and
- developing a substructure test facility to expand test capabilities beyond coupon testing that cannot easily capture the realistic and complex loading modern wind-turbine blades experience.
The latest database (v.22.0) and related publications can be accessed at the Montana State Univ. Composite Technologies Research Group website.