Fatigue Life Testing of Journal Bearings with a New Servo Hydraulic System

Journal bearing fatigue in today's highly loaded internal combustion engines is a problem that requires increased strength bearing alloys. In order to investigate the needs of engine manufacturers, a new servohydraulic test machine has been developed to greatly shorten the test time required to evaluate a material or design change. Three major mechanical components (load frame, hydraulic power supply and lube oil system) are tied into one electrical control console enabling an operator to program test cycles and test parameters similar to actual engine operating conditions Many different bearing sizes can be tested in standardized fixtures of a very rigid design, or actual connecting rods can be used for fatigue testing. The ability to run unattended and at high cycling frequencies allowed a heavy duty aluminum alloy to be fatigue tested in 90 hours where comparable engine tests must be run to 3000 hours.