A study of Fatigue Crack Growth Behavior and Crack Closure in 5083-O Aluminum Alloy

5083-0 알루미늄合金의 疲勞균열進展 擧動과 균열닫힘에 관한 硏究

To establish the evaluation of the fatigue crack growth behavior in 5083-O aluminum alloy, constant load-amplitude fatigue crack growth tests were carried out under the small scale yielding conditions. Crack length and closure of this material were measured by the compliance method using a clip-on gage. The main results obtained as follows: The fatigue crack growth rate against stress intensity factor range .DELTA.K exhibits the trilinear form with two transitions at the growth rate 5.5*10$^{-6}$ and 5.5*10$^{-5}$ mm/cycle, in the so-caled Region II. The trilinear form appears still in the plot of growth rate versus effective stress intensity factor range .DELTA. $K_{eff}$. Stress ratio R affects the relationship of crack growth rates versus .DELTA.K but does not affect the reation of crack growth rate versus .DELTA. $K_{eff}$. The experimental results indicate that the effective stress intensity range ratio U depends on the maximum stress intensity factor $K_{max}$, but not on the stress ratio R.o R.R.

본 연구에서는 균열 닫힘에 관한 연구의 일환으로 5083-O 알루미늄합금을 사용하고 소규모강복조건하에서 일정진폭하중피로시험을 시행하여 이 재료의 피로균열 진전속도와 균열닫힘에 관하여 검토하였다.