Despite the widespread use of fatigue life prediction methods based on integration of the paris equation,the confidence with which the results can be applied is less well established.This paper reports on a rigorous and meticulous evaluation of the Paris -integration fatigue life prediction method using CT specimens of 7075-T6 aluminium alloy fatigued under nominally ideal circumstances.Unlike many industrial situations,in the present study precise values of the Paris equation parameters C and m,fracture toughness,as well a sdimensional aspects,cyclic stress am-plitudes and compliance functions, Y(a/w),were known and used in the prediction of fatigue life-times.the study was undertaken for constant amplitude cycling with R=0.1.for a range of initial and final crack sizes.Despite the ideal conditions and care taken,life time predictions were typically only within factors of 1.5 to 2 times of the actual lifetimes.Electron microscopy studies indicated good correlations with predicted crack growth increments,but lifetime predictions to better than 50
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