RESEARCH ON FATIGUE-CRACK GROWTH IN HIGH-STRAIN REGION OF SCT SPECIMENS

The fatigue crack closure (FCC) and crack growth rate in high strain r egion (HSR) of SCT specimens of 16MnR steel are measured and studied. Test results show that the crack closure in the plastic zone increases and makes the fatigue crack growth rate (FCGR) decrease, and that out of the plastic zone decrease and makes the FCGR increase. The FCGRs i n the high strain plastic zone, in the high strain elastic zone and in non-high-strain zone can be calculated by the same Paris' law, and th e Paris' constants can be gotten from the fatigue tests of CT specimen s of the same material, if the effective stress intensity factor range is used to deal with the FCGR after the crack closure is considered. (C) 1997 Elsevier Science Ltd.