The Fatigue Crack Growth Under Compressive to Compressive Fluctuating Loading

There are some components subjected to compressive and bending loading in ship and offshore structures and fatigue cracks were fond in compressive side of these components caused by fluctuation loadings, during their service. For better understanding the fatigue behavior of these components subjected to compressive to compressive loading, plate specimens with center crack (CCP) and plate specimens with double edge crack (DECP) have been designed for the experiment for examining the fatigue crack growth under axial compressive fluctuation loading. In this paper, a high strength steel plate was used as the test material. Fatigue test has been performed using MTS810 material testing system. Experimental results show that cracks can be propagated under compressive to compressive loading. It also shows that the cracks propagated to a certain length and then arrested completely. The experimental procedure and the phenomena are described. The stress-strain and the residual stress during a cycle were simulated by FEA. The stress intensity factor of the crack by residual stress and its propagation life were estimated and compared with the test data. The residual stress plays a very important role in crack growth under compression to compression fluctuation load.