The effect of forced convective heat transfer on the transient stress intensity factors for longitudinal semi-circular cracks in cylinders

The purpose of this paper is to analyze an internal longitudinal semi-circular crack in a hollow cylinder subjected to thermo-mechanical loading. The inner surface of the cylinder was subjected to both internal pressure and forced convective heat transfer loading where the outer one only was subjected to external pressure loading. The temperature at the outer surface has been assumed to be constant. In order to solve the problem، a three-dimensional finite element model with 20-node singular elements around the crack front was employed. Transient thermal stress intensity factors were obtained for some points of the crack front. Transient thermal stress intensity factor variations along the crack front were calculated for different relative depths and Biot numbers which indicate the type of forced convective heat transfer in different times. In the special cases of loading، the results show to be in accordance with those cited in the literature. The results show that the prescribed temperature at the inner surface of the cylinder is the conservative thermal boundary condition and the corresponding stress intensity factors are the maximum values in any Biot numbers. It is observed that the steady state analysis is the most critical one and possesses the highest value of stress intensity factor along the crack front.