By applying the finite element software ANSYS

numerical simulation on J-integral

stress and strain on HR3Cheating surface with radial cracks for ultra supercritical boilers was conducted

at different temperatures and pressures.Moreover

the area of plastic region was estimated

according to distribution of plastic strain occurred within the crack tip area.Finally

by defining four different integral loops at the crack tip

the J-integral values were calculated.The results show that

the stress mutation occurred at the crack tip and was easy to yield;the area of the crack tip plastic zone belonged to the same level as the feature size of the crack zone;both the pressure and temperature had effects on the fracture parameter J

and the pressure had a more great one.