A method and system method for estimating fatigue damage in a structure obtains fatigue damage data collected using at least one sensor associated with the structure during at least one test operation and also obtains structure use parameter data collected during the at least one test operation. The obtained fatigue data and the obtained use parameter data are used to compute coefficients of at least one generic polynomial function that outputs a fatigue damage value based on inputs representing use parameter data. The at least one generic polynomial function is used to output an estimated fatigue damage value based on inputs representing use parameter data collected during use of the structure.