Truss

This past fall of 2020, I got to work on designing and building a roughly two foot long, 7" tall truss for my statics course. We started off with some materials testing, discovering the properties of our selected wood and glue (modulus of elasticity, bending force (maximum load), maximum shear force), then worked to design a truss that would hopefully break at just after 1200 lbs applied at the top point.

Our design and calculations:

We built our truss over the course of 4-5 hours, taking time to measure extensively, 3D printing the gusset plates, and even printing out a to-scale image to match to. But as most engineers know, a great CAD model does not a great design make... and some errors caused our truss to fail earlier than expected.

Ultimately, while we expected our truss to break at roughly 1600 pounds, accounting for the safety factor of 1.3 our truss broke at a mere 673 pounds due to the point of the applied load not being sanded down, and some slight asymmetry due to our building methodology. In other words, the 2D truss assumption was broken; I have a lot more respect for civil engineers and bridge builders. Still, a fun project and some awesome lessons to be learned with actually building our creations!

Below: our truss- with its 17-some-odd clamps, mid-testing, and post-breaking.