Effect of overload on fatigue crack propagation and monitoring it

Abstract

In the present study a detection method of an overload application during stress cycles under a constant stress amplitude was investigated. Also, the effect of a tensile overload was shown at three R values ; R=0,-1 and -1.5,in order to understand the effects of R on crack propagation after an overload. At a baseline of R=0,after an overload retardation in the crack propagation was observed. However, in the case of R=-1.5,the fatigue crack growth rate actually accelerated after a tensile overload. These behaviors of crack propagation can be monitored by the information of strain waveform, and an overload application can be detected by it.