Development of a New Single Gear Tooth Bending Fatigue Test Capability

In today’s environment, procurement of new ground and air vehicles is sometimes done by modernization and retrofits to existing hardware. Existing drive trains are being asked to carry higher torques and/or speeds for longer service times than what they were originally designed. A key to providing the needed drivetrain improvements is a full understanding of the high-cycle fatigue behavior of drivetrain components. A new capability now joins the existing suite of gear research facilities at the Army Research Laboratory Vehicle Technology Directorate at NASA Glenn Research Center. This capability will allow the testing of gear steels, material and surface treatments being developed. In this new single gear tooth bending fatigue rig, testing will be conducted at rates that will provide high cycle fatigue data in a reasonable time. The test facility has the capability to heat the gear to normal conditions in a gearbox. A unique feature of this facility is the ability to create a fatigue crack in a gear tooth and then run that gear to complete failure in an existing rotating fatigue test stand. This is possible as no gear teeth need to be removed for the single tooth bending test. This test rig provides an excellent resource for Condition Based Maintenance research as there is no need for problematic wireless telemetry or slip rings. The capabilities of this facility are compared to various other gear tooth bending test facilities including the Society of Automotive Engineers (SAE) standard J1619.