Research on stress intensity factor of crack at intersection of crossbores

摘要

Circular crossbore as a common geometric construction exists widely in the engineering components. Its fatigue life is heavily decreased by the crack failure around the intersecting line. So, the typical analysis model of crossbores with mode I crack is built, and the influence of four main parameters, such as thickness–diameter ratio Y , crossbores diameter ratio Q , crack length a , and axis ratio of elliptical crack face b / a , on fracture parameter K I is presented. The results show that the distribution of K I is mainly influenced by Q and b / a , and the influence of b / a is more obvious. The value of K I is mainly influenced by Y, Q , and a , while the influence of b / a is not evident. For elliptical crack face, the K I max (maximum value of K I ) located at the short axis leads to higher crack growth rate. K I max is a crucial factor of fracture criterion, and the significance of factors on it is also analyzed here. A variance analysis of four factors is performed and their order is Y  >  Q  >  a  >  b / a . In addition, a calculation function of K I max is built based on 294 sets’ data and the error is analyzed by mean absolute percentage error with maximum error being less than 7.2%.