Summary of Concept Selection
| Author: Mike Beeman | Team: WERP |
Introduction
The blade foundation, although a small component, provides a critical function to the test bed. It must be sturdy enough to hold up against the required loads without deforming while remaining immovable in reference to the applied loads. Many possible designs for a portable structure were considered. This would allow blades to be field tested and was an attractive addition to the design. It has since been determined that the foundation does not need to be portable.
Preliminary Design Concepts
The original design concept was to use a cage like structure that could be disassembled and moved to any location. A plate that contained the Hub/Blade interface bolt pattern would be mounted to one end of the cage. Follow this link, Preliminary Sketches for conceptual sketches of the inititial mounting plate designs. These plates could be replaced to accommodate future blade/hub interface designs.
Design Selection
A design selection matrix was conducted to find the most effective design. Refer to Table 1 for the results.
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| Table 1. Selection Matrix |
Concept Modeling
Upon selecting Concept B & D a solid model of both designs was constructed for proof of concept. Refer to Figure 2 & 3. Included in the images are the moments and loads that testing would place on the plates. Concept B only required drilling of the plate and bending for the brackets. All materials could be bought pre-manufactured and required minimal machining. For that reason Concept B was selected as a possible solution.
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| Figure 2. Concept B. | Figure 3. Concept D. |
| Click Picture to Enlarge | Click Picture to Enlarge |
System Readiness Review
The design for a foundation has changed sense the preliminary concepts. WERP collaborated on a system readiness review and determined that a portable and collapsible structure is not feasible. It would require excessive strengths analysis to keep the test bed from deforming, material costs exceed the team’s budget, and the benefit of having a mobile system does not out weigh these costs. It was also determined that the torsion testing was unnecessary because the wind turbine simulation software Blade Sim determined there was minimal torsion loads induced by drag forces on the blades. Refer to the Specification page for a detailed description of the final design.
