Abstract
True stress-strain curves of SPR and base materials were estimated by dual indenter method, and pre-strain levels of SPR and base materials were determined by the estimated stress-strain curves. Pre-strained specimens were prepared and conducted fatigue tests. Stress distribution of the SPR and its joints were analyzed by FEM, and fatigue strengths of SPR itself and SPR joints were correlated. Next, fatigue tests of base materials were conducted for 0 % and 10 % pre-strained materials. The results demonstrated that the fatigue strengths became similar by the pre-strain for different strength base materials.
