Hold-Time Effects in Elevated Temperature Fatigue Crack Propagation
Abstract
An experimental investigation was conducted to evaluate the effects of hold-times on the fatigue crack growth rate of Inconel 718 to 649 C using compact tension specimens. Tests were run under computer controlled constant K conditions using compliance to determine crack length. Hold-times ranging from 5 to 50 s were applied at maximum, minimum, and intermediate load levels. The data show that hold-times at maximum load were the most damaging in terms of crack growth rate. Hold times greater than 5 s led to purely time-dependent crack growth behavior which was predictable from sustained load data using K as a correlating parameter. Hold-times at a minimum or intermediate load levels had little or no effect on crack growth rate. A linear cumulative damage model based solely on fatique and sustained load data was found to be adequate for spectrum loading as long as the hold-times were at maximum load. Additional keywords: gas turbine engines; Air Force equipment; aircraft engines. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1985
- Accession Number
- ADA154146
Entities
People
- T. Nicholas
- Tusit Weerasooriya
Organizations
- University of Dayton