FATIGUE STRENGTHS OF AIRCRAFT MATERIALS AXIAL-LOAD FATIGUE TESTS ON NOTCHED SHEET SPECIMENS OF 24S-T3 AND 75S-T6 ALUMINUM ALLOYS AND OF SAE 4130 STEEL WITH STRESS-CONCENTRATION FACTORS OF 2.0 AND 4.0

摘要

This report presents results of axial-load, fatigue tests on notched specimens of three sheet materials:24S-T3 and 75S-T6 aluminum alloys and normalized SAE 4130 steel. Notches included:n(1) Stress-concentration factor 2.0:Central circular hole, symnmetrical edge notches, and filletsn(2) Stress-concentration factor 4.0:Symmetrical edge notchesnand filletsnFor each type of specimen, fatigue tests were run at several levels of nominal mean stress, including a zero nominal mean stress.