Consideration on Crack Initiation Life under Programme Fatigue Test

Abstract

Programme fatigue test is a one under the cyclic loading as a block which has a number of cycles of load with some kinds of amplitude of stress. This test is to acess fatigue strength of products under modified conditions near to actual load. Many kinds of block patterns are inevitably to be considered. On fatigue design of products, programme fatugue test under some block patterns are examined for the restriction of time and cost and a study on lifes for the other patterns is done with the application of Miner's rule, modified Miner's or Haibach's method. Unfortunately, the estimated lifes irrespective of the above methods are widely scattered in comparision with experiments. This paper describes a proposal of the dependence of block patterns on crack initiation life for programme fatigue.