Patent ID: 7844428

Claim:
A method for assessing heating-induced, life-affecting damage to a rotary member that is subjected to cyclical, heat-generating loading, said method comprising: a) calculating a heating parameter that is based on the thermal diffusivity constant α of the rotary member and the length of time for which the rotary member is subject to a given cycle of heat-generating loading, where α=λ/(ρ*c), λ, is the thermal conductivity of the rotary member, ρ is the density of the rotary member, and c is the heat capacity of the rotary member; b) selecting a function and calculating a maximum temperature associated with the rotary member for the given cycle of heat-generating loading using the selected function, wherein one function is selected if the heating parameter is less than a predefined limit value; wherein another function is selected if the heating parameter is greater than said predefined limit value, said another function intersecting said one function at said predefined limit value; and wherein either said one function or said another function is selected if the heating parameter is equal to said predefined limit value; c) repeating steps a) and b) over the course of a multitude of heat-generating loading cycles; d) tabulating the number of heat-generating loading cycles which have occurred in each of a plurality of pre-defined temperature categories, wherein each of said pre-defined temperature categories corresponds to a range of maximum temperatures that may be generated in association with the rotary member in any given cycle of heat-generating loading; and e) using the tabulated number of heat-generating loading cycles which have occurred in each of said plurality of pre-defined temperature categories and using pre-established, heating-related life expectancy information for said rotary member, assessing a cumulative amount of heating-induced damage which has occurred to said rotary member using a partial damage theory; wherein said steps a) through e) are executed automatically on electronic computing means and wherein said method further comprises outputting from said electronic computing means a signal that is indicative of the cumulative amount of heating-induced damage which has occurred to said rotary member.