Accession Number : ADP001610

Title :   Crack Propagation at Short Crack Lengths under Variable Amplitude Loading (2nd Report),


Personal Author(s) : Cook,R. ; Edwards,P. R.

Report Date : APR 1983

Pagination or Media Count : 19

Abstract : An experimental programme was carried out to investigate short crack anomalies whereby short cracks propagate faster than long cracks at the same calculated stress intensity factor. This paper is the second to be issued on this programme and contains all results to date. Fatigue tests were carried out on notched 2L65 aluminium alloy specimens under constant and variable amplitude loading. Measurements of corner cracks growing from holes were taken down to crack lengths of 0.01mm using replicas. Under constant amplitude loading short crack anomalies were identified at zero mean stress but not at R=O (zero to peak) loading. Under Gaussian random loading much greater anomalies were identified.

Descriptors :   *Airframes, *Cracking(Fracturing), *Structural mechanics, Crack propagation, Loads(Forces), Fracture(Mechanics), Fatigue(Mechanics), Stress analysis, Aluminum alloys, Sizes(Dimensions), Mathematical analysis

Distribution Statement : APPROVED FOR PUBLIC RELEASE