Designing a Two-Stage Reduction Gearbox: FEA and Fatigue Analysis
Group Project, MECE09033 Manufacture 3, University of Edinburgh, 2024
Our brief was to design a two-stage reduction gearbox taking 50 Nm in and stepping down a 19:1 ratio, built to survive 100,000 hours of operation. My responsibilities were the FEA and Goodman (fatigue) analysis on the shafts and housing, plus material selection, and I also helped with the final assembly animation.
Static strength isn't the real constraint on a rotating shaft — fatigue is, since cyclic loading can cause failure well below a material's ultimate strength. I ran stress FEA across each shaft and plotted the results against a Goodman diagram to confirm every critical section held a safe margin, then applied the same approach to the housing.
Beyond the analysis itself, this project taught me a lot about resilience — chasing design issues through repeated rounds of re-simulating and adjusting, and the particular grit that comes from wrestling with unfamiliar software (Onshape's simulation and animation tools, new to all of us) until it finally does what you need it to.