抄録
The study has clarified the relationship of fatigue strength reduction factors K_f of engineering plastics PBT, PEEK, PC between strain concentration factor K_ε in the region of high- and low-cycle fatigue. In this study, we proposed new method of calculation on the basis of the size-effect defined on the ratio of notch to smooth fatigue damaged area. In order to verify the new Kf calculation method to consider the size-effect, elastic-plastic simulation FEM analysis and elastic-plastic fatigue tests fatigue area of carried out on specimens with four kinds of elliptical hole which are made of PBT, PEEK and PC. As results of experiments and calculation, it is clarified that there is the proper relationship between K_f and K_ε in PBT and PEEK, on the other hand, there is not good relation in PC.
