FATIGUE STRENGTHS OF AIRCRAFT MATERIALS AXIAL-LOAD FATIGUE TESTS ON EDGE-NOTCHED SHEET SPECIMENS OF 2024-T3 AND 7075-T6 ALUMINUM ALLOYS AND OF SAE 4130 STEEL WITH NOTCH RADⅡOF 0.004 AND 0.070 INCH

摘要

The present report gives results of axial-load fatigue tests on notched specimens of three sheet materials:2024-T3 and 7075-T6 aluminum alloys and normalized SAE 4130 steel.nTwo edge-notched specimens were designed and tested, each having a theoretical stress-concentration factor Kt=4.0. The radii of the notches were 0.004 and 0.07Q inch. Tests of to be specimens were run at two levels of nominal mean stress:0 and 20,000 psi.nResults of these studies extended information previously reported on tests of specimens with varying notch severity. They afford data on the variation of fatigue-strength reduction with notch radius and on the potential usefulness of Neuber's technical stress-concentration factor Kn.