Stresses and Strains Around Open and Filled Holes in an Aluminum Sheet During Cyclic Loading.
NAVAL AIR DEVELOPMENT CENTER WARMINSTER PA AERO STRUCTURES DEPT
Pagination or Media Count:
The stress and strain history at a point of stress concentration were studied in an effort to resolve conflicts regarding the effects of spectrum block size in fatigue testing. Fatigue tests were performed using as specimens large sheets of 7075-T6 aluminum alloy with a central hole. Plastic deformation was induced at the edge of the hole, although the gross area stress in the sheet remained in the elastic range. It was found that the strains at the stress concentrator varied during subsequent constant-amplitude fatigue cycling. Relaxation of the mean stress and strain hardening were qualitatively detected. Author