Balsa Wood Truss

Design report
Mechanical truss prototype using balsa wood
February 2017-April 2017
Built With: Balsa wood, pine wood dowels, Gorilla glue Tool used: SolidWorks, OnShape, laser cutter, AutoCad
The term project for Mechanics of Deformable Solids. The problem proposed was to design, analyse and construct a 3D truss in cantilever, using balsa wood as truss members and wooden dowels as joints, optimized to carry the maximum load, while itself having the minimum weight.

Our team's truss was unique in utilizing a box beam compression member, which optimized its weight to second moment of inertia ratio, because it was found through initial testing that buckling was the limiting failure mode. Our truss was ultimately the best performing of the class, and had the best performance score (load carried vs truss mass) of the past three years that this project has been conducted.

I was responsible for optimizing the joint geometry, and CAD of the final assembly in Solidworks and OnShape (online CAD modelling tool). I was also the member responsible for laser cutting the components, and led the testing of all our components.

3D CAD of final design

Different joint geometries evaluated during testing

Me loading the truss during competition day

Slow motion capture of the truss (weighing 16.1g) failing under compressive stress at a loading mass of 7.5kg