Review and Analysis of Cumulative-Fatigue-Damage Theories

Abstract

Abstract : This Memorandum contains the resu a study of cumulative fatigue damage. It shows that there are certain key assumptions which can be identi fied in current theories. These assumptions determine general trends in the structural weight required to provide a satisfactory fatigue life when a particular theory is used for fatigue-preventive design of a flight structure. The key assuittions have to do with the way fatigue damage is assumed to occur at different stress amplitudes when they are applied alone and when they are mixed with other stress ampli tudes (as is the case in aircraft). (Author)