Study on creep damage and crack growth for TC11 under complex stress loading

Abstract

In order to investigate the creep damage and creep crack growth of TC11, we established the finite element model based on ductility exhaustion constitutive model. This paper uses the uniaxial creep test of TC11 at 500℃ as a reference and studies the effect of initial crack dimensions on crack growth of CT specimen and surface crack specimen. The initial crack length of CT specimen has a significant effect on creep crack growth of TC11 material. The larger the initial crack length, the higher the crack growth rate, the crack tip equivalent stress and the crack tip stress triaxiality. The initial crack length has a greater influence on creep crack growth for deep crack specimens(a0/W=0.6, a0/W=0.7) than that for shallow crack specimens(a0/W=0.3, a0/W=0.4, a0/W=0.5). When the stress intensity factor Kπ/2 at the deepest location of surface crack is the same, the crack growth length of each specimen in the depth direction at the same time is approximately twice as much as that in the length direction. With the increase of initial crack size, the crack growth rate of surface crack decreases gradually. And the effect of initial crack length on crack growth is greater than that of initial crack depth.