Application of a failure assessment diagram under rolling contact to components with hardness variable along the depth

摘要: Abstract A development of a failure assessment diagram for the evaluation safe working area components subjected to rolling contact loading is here presented regarding application whose hardness varies along depth. The approach takes into account influence inherent defects in determining subsurface fatigue, depending on conditions, material properties and profile For this aim, crack propagation from assessed terms applied stress intensity factor range normalized with respect short growth threshold, defect – free fatigue Dang Van shear limit, where quantities depend variable These two are coordinates points “reference curve” diagram, which location indicates whether expected occur. By analysing different combinations condition, inclusion dimension profile, it was possible obtaining design general validity, allows fast prediction safety against fatigue.