In this work, fatigue tests by axial loading were carried out to investigate the effect of stress ratio on the growth behaviors of surface fatigue crack for SM45C steel and Al 2024-T4 alloy. The growth behaviors of surface crack have been monitored du...
In this work, fatigue tests by axial loading were carried out to investigate the effect of stress ratio on the growth behaviors of surface fatigue crack for SM45C steel and Al 2024-T4 alloy. The growth behaviors of surface crack have been monitored during fatigue process by measuring system attached CCTV and monitor. When the growth rates of surface crack were investigate by the concept of LEFM based on Newman-Raju's ΔK, the dependence of stress ratio appears both SM45C steel and Al 2024-T4 alloy.<br/>
Therefore, modified stress intensity factor range, ΔK [=(1+R)<SUP>n</SUP>ΔK] are introduced to eliminate the dependence of stress ratio.<br/>
Using ΔK, it is found that the dependence of stress ratio disappears both SM45C steel and Al 2024-T4 alloy.