PATH-DEPENDENT CYCLE COUNTING AND MULTI-AXIAL FATIGUE EVALUATION OF ENGINEERING STRUCTURES

摘要

A method is provided for performing fatigue evaluation of a fatigue prone location of a tangible structure by converting multi- axial loading data of the fatigue prone location of the tangible structure to a set of equivalent constant amplitude loading data for the tangible structure. According to the method, a multi-axial load locus representing the tangible structure is generated. Time-dependent interior turning points R and any corresponding projected turning points R* are identified along the loading path from the point of origin P to the point of termination Q. Half cycles in the loading path are counted by referring to the interior and projected turning points R, R* along the loading path and to the point of origin P and the point of termination Q on the load locus. A stress range Δσe, loading path length L, and virtual path length for each of the counted half cycles are determined. Additional stress ranges Δσe, loading path lengths L, and virtual path lengths are determined recursively for half cycles counted in additional loading paths on the load locus. A system is also provided for performing fatigue evaluation. Methods are also provided for counting and displaying the number of load cycles represented in multi-axial loading data of a fatigue prone location of the tangible structure. Additional embodiments are disclosed and claimed.