2. Assumptions

The hypotheses used to build the 1D crack model are:

• the rotor has isotropic elastic behavior;

• the crack may be of any shape but it is contained in a section of a beam;

the crack lips are connected by a*without friction contact condition;

• normal and sharp forces are neglected (under certain hypotheses torsional forces can be taken into account but within the framework of this element they are forgotten);

• the initial crack play is zero;

• the behavior of the crack is almost static and the effects of inertia are negligible.