CONSIDERAZIONI TEORICHE E PRATICHE SUL METODO DEL MASSIMO udRETTANGOLO CIRCOSCRITTO PER LA VALUTAZIONE DELL’AMPIEZZA DELLA udTENSIONE TANGENZIALE NEI CRITERI DI FATICA MULTIASSIALE BASATI udSULL'APPROCCIO DI PIANO CRITICO

摘要

The multiaxial fatigue criteria based on the approach of the critical plane require the determination of udthe amplitude of the alternating shear stress τudaacting on different planes passing through the point of udthe material analyzed. In the case of non-proportional stresses the shear stress vector varies both inudmodulus and direction and its tip describes a curvedefined loading path. In these cases τudais identified udand evaluated by means of special procedures the most recent, and apparently more effective, of which udis that of the Maximum Circumscribed Rectangle (MCR) to the loading path itself. In particular τudais udequal to the length of the diagonal of the MCR. In this paper, the MCR method is analyzed comparing udit with other existing methods in terms of results obtained and computational effort. Furthermore two udprocedures that help to optimize the performance ofthe method are proposed, then some critical udaspects of the method itself are highlighted for future development of the technique.