Constant Stress Amplitude Fatigue Crack Growth in Notch Pre-cracked Aluminum 7075-T6 Rivet Hole

Constant stress amplitude fatigue tests were conducted on the notch pre-cracked Aluminum 7075-T6 rivet hole dog-bone coupons. Monitoring of visible surface crack length by special surface engraving using digital microscope images and by ultrasonic sensors signals was carried out to yield fatigue crack length measurements in relation to number of fatigue cycles applied. The experimental results provided fatigue crack length validation for the ultrasonic sensor measurements. Fracto-graphic examination of failed fatigue surfaces yielded further confirmation of notch pre-crack length and crack growth marker bands. These experimental inputs were used in NASGRO and AFGROW software applications, for fatigue crack growth simulation. Comparative analysis of simulation and experimental fatigue crack growth results is presented in this paper. Opportunities for further work are discussed.