Abstract: The material fatigue damage accumulation procedure under complex loading is analyzed, and the relation between material fatigue damage of fatigue life gage itself under alternating loading and its permanent resistance change response to fatigue is discussed.The resistance accumulation quantity and resistance change rate reflect the material damage quantity and its evolution pattern. The fatigue equivalent average damage and damage accumulation procedure of the fatigue life gage material itself, displayed by the resistance change character are assumed to generally exist in common material.The equivalent resistance accumulation quantity corresponds to common metal material fatigue equivalent average damage quantity; fatigue failure damage quantity is not a constant value, but equal to the value at the point where the faitigue failure life curve and fatigue equivalent average damage curve intersect. A new stress cyclic number to failure curve suitable for most material from low to high stress cycle is developed. A new calculation method is advanced of material remaining life for random loading by using the fatigue failure curve and material equivalent average damage curve. This method is reasonable and quite satisfactory in the preliminary experimental verification.

Key words: random loading, equivalent damage, remaining life, life pr ediction