Abstract: Aiming at the mixed mode crack, which is commonplace in practical engineering, an energy calculation model based on elastic fracture theory and complex variable function theory is built in order to study the change law of system energy under the effects of various relative factors, during crack propagation. Taking the I, II mixed mode crack for example, the effects of external load, crack angle, geometrical sizes of crack and others factors on system energy are calculated completely. The change of system energy of mixed mode crack is compared with that of mode I crack based on different crack angle. It is shown that with the increasing of external load and crack angle, the system energy increases. And with the increasing of crack length, the system energy decreases. When the external load and crack length equal to zero, the energy also equals to zero. Moreover, at the same external load and boundary conditions, the energy of mixed mode crack with certain crack angle is bigger than I mode crack.

Key words: Stress intensity factor, Crack propagation, Mixed mode crack, Simulation calculation, System energy, consistency, gas fraction, performance characteristics, rotational speed, vacuum pressure, medium consistency pump