A machinery component operates under a cyclic load conditions with the tensile stress changing with time, t, as 0 x = Ao 1 + (sin(2 t/T)) and the shear stress changing with time as Txy = At (1 + (sin(2 t/T)) (note that period T is the same for the tensile stress and the shear stress). In every 100 randomly mixed cycles there are: 60 cycles with Ao =50 MPa and A =30 MPa and 40 cycles with Ao = 80 MPa and At = 50 MPa. The material of the component has the properties with: E=205 GPa, 0y =340 MPa, UTS = 440 MPa, Kic-135 MPa-m'2, and the Paris law constant A = 3.8 10-11 m/cycle (MPam" The component contains a surface crack with the initial depth of 2 mm. Estimate by calculation the number of the load cycles within a safe service period. Assume that the crack grows along the plane, normal to the direction wherein the maximum tensile stress is acting. Assume that the stress intensity can be calculated as: Kj=1.270 Va, where a is the crack depth.