Papers by Keyword: Corner Crack

Abstract: This note is specifically concerned with cracks emanating from a quarter-spherical cavity on the edge in an elastic body (see Fig.1) by using finite element method. The numerical results show that the existence of the cavity has a shielding effect of the corner crack. In addition, it is found that the effect of boundaries parallel to the crack on the SIFs is obvious when.H/R≤3

Abstract: The fatigue testing of the specimen with a central open hole was carried out to investigate the influence of the surface roughness on the fatigue lifetime. Fracture morphology investigations were used by scanning electron microscope. The reliability analysis of the specimen was carried out by detail fatigue rating. The results revealed that the less the roughness is, the longer the fatigue life of open hole and the higher the value of DFR (Detail Fatigue Rating) is. Under the same technological conditions, the effect of corner crack on fatigue life of open holes is greater than the effect of internal crack. So, the effect of a decrease of roughness on the fatigue life of an open hole is similar to a change of crack type from a corner crack to an internal crack.

Abstract: This investigation aims at doing some durability and damage tolerant (DaDT) tests with 2124-T851 aluminum specimens having corner cracks under a random history, correlating with the simulation results from AFGROW and then drawing some conclusions from those comparisons. Two hydraulic actuators and a homemade Wood’s alloy grip are employed to do the test. The surface crack lengths are measured by a traveling microscope and used as a reference for the later fractography. The crack penetration and the total lives are about 17 and 27 blocks, respectively. The crack length and depth are evaluated by the fractography after completing each test and used to grasp the shape change. The Forman equation is used to simulate the fatigue crack growth behavior according to a bearing stress ratio extensively. The crack penetration life is decreased as the bearing stress ratio increases. The crack aspect ratio is very dependent on the bearing stress ratio. The LBH loading accelerates the fatigue crack growth in the crack depth direction but decelerates that in the length direction until crack penetration.