Critical plane approaches in high-cycle fatigue: on the definition of the amplitude and mean value of the shear stress acting on the critical plane
Critical plane approaches are useful methods for the design against long term fatigue of machine components made from mild metals. The basic problem of the evaluation of the amplitude and mean value of the shear stress acting on the critical plane is still not resolved satisfactorily for non-proportional cyclic loading conditions. Existing proposals for solving this problem are reviewed and their weaknesses are highlighted. It is shown that application of these proposals can lead to ambiguous results. New definitions of the amplitude and mean value of the shear stress acting on the critical plane are formulated that are free from ambiguity because they are based on the construction of the (unique) minimum circumscribed circle to the path described by the shear stress on the critical plane. The centre of this circle defines the mean shear stress, whereas its radius provides the corresponding shear stress amplitude. The algorithm yielding this minimum circumscribed circle is presented in some detail.
Bibliographic Reference: Article: Fatigue and Fracture of Engineering Materials and Structures
Record Number: 199710395 / Last updated on: 1997-04-23
Original language: en
Available languages: en