Fatigue Crack Growth Equation considered the Effect of Stress Ratio |
|
|
응력비의 영향을 고려한 표면피로균열의 균열성장식 |
강용구,김대석 |
금오공과대학교 기계설계공학과,한국파워트레인㈜종합기술연구소 |
|
© 1998 The Korean Society of Ocean Engineers
Open access / Under a Creative Commons License
|
Keywords:
Stress Ratio, Critical Crack Length, Dependence of Stress Ratio, Aspect Ratio, Crack Growth Equation, Modified Stress Intensity Factor Range |
핵심용어:
응력비, 임계균열길이, 응력비 의존성, 형상비, 균열성장식, 수정응력확대계수범위 |
Abstract |
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 .DELTA.K, the dependence of stress ratio appears both SM45C steel and Al 2024-T4 alloy. Therefore, modified stress intensity factor range, .DELTA.K' [=(1+R)/sup n/.DELTA.K] are intorduced to eliminate the dependence of stress ratio. Using .DELTA.K', it is found that the dependence of stress ratio disappears both SM45C steel and Al 2024-T4 alloy. |
|