A discussion of fatigue properties of notched specimens subjected to prestressing treatment machined from FGH4097

Abstract

Experimental and numerical investigations were performed to reveal the effect of prestress on the fatigue properties of FGH4097 so as to quantitatively evaluate the overspeed benefit of the disc of aeroengine. A corresponding experiment was performed to examine the effect of prestress on the fatigue life of FGH97. A complete model describing the fatigue properties of the prestressed notch specimen was proposed. After the modification of mean stress, stress gradient and prestressing treatment, the model is finally verified by fatigue test of presstressed notch specimens machined from FGH4097 with satisfactory accuracy and good engineering applicability. The new model highlights that for the variable fatigue loads, the introduction of appropriate prestress is expected to benefit to the notch specimens and certainly to the disc of aeroengine regards of their fatigue properties. Both the calculation method of fatigue life parameters and the prestress correction model are proved to have good prediction accuracy.