• subcritical crack growth
• fem
• elastic-plastic materials

The objective of this thesis is to study the dependence of the P method on
the geometry of the specimen, crack length and applied load. We will try to
show how such constant value of the trace of the energy momentum tensor is
achieved in conjunction with the propagation of the crack (thus with the break
in the material microstructure); will also be interesting to show how this value is
an intrinsic characteristic of the material in analogy to that seen for the critical
value of the Stress Intensity Factor. In order to do this crack propagation in
thin-walled panels of two dierent aluminum alloys will be studied and, for one
of these, we will study the crack propagation starting from four dierent initial
crack length. Simulation will be carried out according to the assumption of
Plane Stress. A further simulation will be carried out to show the behavior of
the specimens according to the Plane Strain assumption.