The goal of this project was to build a boom tower out of Pre-preg carbon-epoxy that could be rolled up into a drum and then deployed once on the moon.
The first step was to design the cross section of the boom tower. The cross section created needed to be able to support at least 5 kg on top of a boom that would be 16 m long. At the same time however, the cross section needed to be able to not only flatten, but then the flattened boom needed to roll up around a drum that was about 12" in diameter.
In order to solve this, me and my team developed MATLAB code that could evaluate a potential cross section using the geometrical parameters, number of plies in each section, and the material properties of the carbon-epoxy itself.
The finalized cross section, along with the material parameters, is below.
After the cross section design had been finalized, the next step was to conduct extensive analysis on the boom tower. The plan of the project was to manufacture a 6ft section of the boom tower and run tests of bending in the soft direction, minimmum buckling load, and vibration. The vibration tests included approximating natural frequencies as well as putting the boom through a simulated moonquake. (The Moon has seismic activity too). If the analysis done in MATLAB and ABAQUS was accurate to the tested results, the analysis could in theory then be extrapolated to a 16 meter long full scale boom tower.
The boom was manufactured in 6' long aluminum molds, one half at a time. One half of the cross section was manufactured, and then the other. After which they were joined by an adhesive at the flanges.
Throughout the manifold project, my main task was the design and manufacturing of the manifold.
The manifold has two functions. The first is to make the boom go from flat to open or open to flat. Ideally it does this with the least amount of resistance. The second function is to provide a "clamped" condition to the base of the boom to effectively make it a cantilever beam. This requires the most precise manufacturing at the open end of the boom, so that the manifold could be hugging the boom and applying some pressure to it without compromising the shape.
In order to do this, I used the Finite Element Analysis software ABAQUS to perform a nonlinear analysis of flattening the boom. I flattened the boom at one end and used the shape given in ABAQUS to guide my design of the manifold in Solidworks.
Once the manifold was built, I performed an analysis of the root stiffness the designed manifold provided, again using FEA. The results are pictured below.
The boom failed at similar loads as predicted, and in the manner predicted. That is, buckling occured at the predicted load and in the flanges of the cross section. Transverse bending made the boom fail at 15 lbs, as predicted, and the crack occurred at the top and bottom of the cross section.
The boom was able to make a full revolution around the drum with reasonable resistance, but the adhesive holding the two halves of the boom together came apart in some sections. Future variations of this project will allow the two halves to slide to prevent shearing of the adhesive.
The goal of this project was to develop a fan blade for a wind turbine that would be as efficient as possible. The weight of the blade as well as the power produced by the wind turbine were all considered in the evaluation of blade design. This was more of a fun project that didn't require too much analysis. The real point of it within the context of my education was to gain familiarity with composites such as the fiber glass-epoxy plies the blade was made of.
The general idea was to take a chord shape from airfoiltools.com and import the coordinates of the shape into Solidworks. After which, multiple sketches of the chord shape would be lofted together. The challenge was what angles and lengths at different points along the blade would yield the best results.
My group and I decided to go for maximum power and worry about the weight later. So we found a software called Q-blade where you can test the proficiency of any blade you like. We took turns plugging in all kinds of blade designs, and eventually the tests converged on what became our final design.
And here is a model of the mold that the blade was created from.
My groups cavalier approach to the design process gave some exciting results. The wind turbine produced an rpm of 550 with one configuration, before the wind turbine forcibly shut off. The wind turbine had a safety feature in case of hurricanes that our blade activated in the wind tunnel.
We had a lot of fun with this project.