Influence of Programing Techniques and of Varying Limit Load Factors on Maneuver Load Fatigue Test Results
Abstract
Variable-amplitude axial-load fatigue tests were conducted on 7075-T6 aluminum-alloy edge-notched specimens having a theoretical elastic stress concentration factor of 4. The load programs were designed to approximate maneuver load spectra. Fatigue life was found to be shorter for random form tests than for block form tests having the same load spectrum. The greatest change in life occurred when the test program contained negative loads. Life for variable-amplitude tests was found to increase as much as 60 percent above the original test life after preloading with a program having a higher limit load factor. The summations of cycle ratios were approximately 2 for tests without negative loads but were approximately 1 for tests with negative loads.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1966
- Accession Number
- ADA447634
Entities
People
- Eugene C. Naumann
- Patrick L. Corbin
Organizations
- National Aeronautics and Space Administration