Assumptions
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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.