Cumulative Damage in Fretting Fatigue of Pinned Joints Subjected to Narrow Band Random Loading

Abstract

SummaryFatigue tests have been made in constant amplitude loading and in narrow band random loading on FV520B steel lugs of width 27 mm loaded by means of a pin 12·7 mm in diameter. The test frequency was 220 Hz, a mean tensile stress of 309 N/mm2 was used and tests extended for endurances of up to 109 cycles.For endurances up to 106 cycles there was good agreement between constant amplitude and random loading results with both stresses expressed in root mean square values. Beyond this endurance, the random loading results lay below those obtained in constant amplitude loading. Predictions made using the Palmgren-Miner cumulative damage hypothesis in conjunction with the endurance curve in constant amplitude loading gave good agreement with the results in random loading over the whole range of endurances tested.