Shaft Twist Inspection Tool

Since its design, the U.S. Army has reinforced a specific combat vehicle with additional armor, nearly doubling its original weight. With the added load, the vehicle's differential components can fail, and a particular splined shaft is the weak link. To maintain these vehicles, the Army periodically disassembles and rebuilds them, at which time they inspect this splined shaft. The shaft is rejected for reinstallation if it has any signs of plastic twist deformation. Currently the shafts are visually inspected, but angles of twist less than 1° are undetectable to the naked eye. The U.S. Army Materiel Systems Analysis Activity (AMSAA) has requested that 3AS Engineering, a University of Wyoming Mechanical Engineering Senior Design team, design an inspection tool that can detect angles of twist less than 1°. This tool must have a resolution of 0.01°, an inspection duration of ≤ 5 minutes, and operate with shafts of varying diameters and lengths. The amount of deformation on the shaft surface corresponding to twist of 0.01° is less than the machining tolerances indicating no single measurement on the shaft could decipher between twist and machining effects. This is overcome by taking thousands of measurements and statistically analyzing the data to detect trends indicating twist. The tool will be delivered to AMSAA in May 2013.