SEDL / STP / STP1292-EB / STP16136S

A Study of Naturally Initiating Notch Root Fatigue Cracks Under Spectrum Loading

Prakash, RV
National Aerospace Laboratories, Bangalore,

Sunder, R
Biss Research, Bangalore,

Mitchenko, EI
Visiting scientist, Kiev Institute for Strength Problems, Kiev,

Pages: 25    Published: Jan 1996

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Abstract

The kinetics of short cracks at notches were studied in 2014-T6511 Al-Cu alloy extruded bar stock under modified versions of FALSTAFF and TWIST load spectra. Experiments were conducted on test coupons of different thickness and at different stress levels. The effects of these and other parameters on the density and growth rate patterns of multiple cracks were investigated. The quality of fractographic crack growth rate measurements was found to be superior to surface replica technique. It was also observed that artificially initiated fatigue cracks grow slower than naturally initiated ones. Interaction of naturally initiating multiple cracks was quantified.