Patent ID: 8839679

Claim:
A method of determining material constants of a hardened metal object being subjected to rolling contact fatigue, the method comprising the steps of: performing at least two fatigue tests with varying ambient and internal parameters such that each of the at least two fatigue tests is conducted with using at least one of a different constant temperature and a different constant pressure, each of the at least two fatigue tests applying continuous pressure to the hardened metal object throughout the duration of the test so as to form at least one groove in the hardened metal object resulting from contact between the hardened metal object's exposure to rolling contact fatigue, the continuous pressure being applied by at least one rolling element such that the number of stress cycles in a load cycle of the hardened metal object is equal to the number of the at least one rolling elements; determining a relative magnitude of subsurface plasticity processes governing damage evolution of the hardened metal object based on the at least one groove formed during the load cycles by rolling contact; and determining the material dependent constants of the hardened metal object based on determining the relative magnitude of the subsurface plasticity processes versus the load cycle for each of the at least two fatigue tests performed, the determining of the material dependent constants comprising analyzing the relative magnitude of subsurface plasticity processes versus the load cycle for the at least two fatigue tests.