Abstract: Size effect on initial flaw size is a reasonable explanation to "size effect on fatigue life". In this paper, the size effect on initial flaw size is studied and an analysis model is also established. With a known initial flaw size distribution for small specimen and an area ratio, the unknown flaw size distribution for large specimen can be gotten by using the analytical model only if these two structures have the same material and machining conditions. It makes great contributions to structural integrity program. It is also helpful to the studies of durability analysis and total fatigue life prediction by using small crack theory.

Key words: size effect, durability, initial flaw size distribution, integrity