Thermal fatigue failure of fuel spray bars of a jet engine afterburner

A JC-integral fracture parameter for the safety assessment of components with more complex loadings was given in the paper, and it was carried out with 3D finite element method. Moreover, the cyclone separator of catalytic cracking unit, which is a typical double-layer high-temperature component, was taken as the practical application case. From the test results, it can be concluded that the high temperature fracture toughness JIC of cyclone separator has decreased significantly after long service. In this condition, the JC-integral can provide us warranty to conclude whether the fracture of cyclone separator will occur under normal loading situation. By comparing the JC-integral value with the experiment test value JIC, the probability of fracture is very small under normal service situation unless there are very long cracks (over 100 mm) in the cyclone separator. Hence the JC-integral can be regarded as an effective fracture parameter for evaluating the safety of double-layer high-temperature components.