Factors Influencing Low-Cycle Crack Growth in 2014-T6 Aluminum Sheet at -320 F (77 K)
Abstract
An investigation was conducted to determine the low-cycle (under 10 000 cycles) crack growth characteristics of through- center- cracked specimens 0.060 in. (0.152 cm) thick subjected to tension-tension cyclic loading. The following factors were studied: (1) minimum to maximum initial stress intensity ratio R (sub i); (2) the maximum gross stress applied, as percentage of critical fracture stress; and (3) cyclic rate. The crack growth rate was found to be a function of stress level expressed as percentage of critical fracture stress for specimens tested at the same R. value. A crack growth relation was developed which takes into account changes in R. in the low-cycle region. When the cycle rate was decreased from 0. 5 to 0.05 Ha, the cyclic life was reduced, but only for high initial stress intensities.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1969
- Accession Number
- ADA379961
Entities
People
- Timothy L. Sullivan
- William S. Pierce
Organizations
- National Aeronautics and Space Administration