Life prediction analysis based on a local strain approach for shafts under torsional loading

The use of low cycle fatigue methodology to evaluate the life expectancy of a structure is on the increase in the last years. This is connected also to the use of computer programs that permit evaluation of stress and strain concentration factors in the plastic field. In this paper the principal procedures used to predict the life expectancy of a mechanical component subject to a biaxial stress state are presented and discussed. The experimental work is connected with torsional loadings on large turbine–generator shafts due to electrical disturbances.