Load Ratio Dependence of Fatigue Threshold in Aermet 100 Steel,
Abstract
A study was conducted on the fatigue crack growth behavior of AerMet 100 steel at various load ratios in a gaseous dry nitrogen environment. Increasing the load ratio increased the near-threshold fatigue crack growth rate and reduced the threshold stress intensity range for fatigue crack growth, DeltaK sub th. DeltaK sub th decreased with increasing load ratio up to a critical value, R sub cr = 0.5, and then leveled off. The maximum stress intensity at threshold, K sub max, changed little below R sub cr but increased rapidly above R sub cr. The critical threshold stress intensity range, DeltaK sub th and the critical maximum stress intensity, K max were determined to be 2.22 and 3.42 MPa sq root of m, respectively. The fatigue crack growth behavior changed from Class-IIb to Class-IIa with increasing fatigue crack growth rate.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 02, 1996
- Accession Number
- ADA321865
Entities
People
- Eun U. Lee
Organizations
- Naval Air Warfare Center