In the below figure, a surface through crack is shown with an initial
crack length of 3mm and a critical crack length of 6.57mm. If an
alternating stress of 458.33 MPa is applied to the figure axially as
shown and the Paris Constants are
and n is 3;
How many cycles will the member be able to withstand before the crack
propagates to its critical fracture length? Use a material constant of
0.099.
Figure 13:
Central Through Crack from Problem

Figure 14:
Paris Equation (a is crack length; Np is Number of cycles till critical crack length;
is alternating stress)
