ESTIMATION OF CREEP BUCKLING DEFORMATION UNDER EXTERNAL-PRESSURE AT ELEVATED-TEMPERATURE

The effect of the initial ovality, wall thickness, and pressure level on the collapse time of a heat transfer tube subjected to both constan t and cycled external pressure at elevated temperature was examined ex perimentally and analytically. The creep deformation of the tube obtai ned by FEM code and the simplified method was a good approximation. Th e simplified method proposed by Nishiguchi et al. is an effectual meth od in the estimation of the creep buckling deformation and the collaps e time of the tube under external pressure at elevated temperature as compared with the experimental results and the FEM. Though many cracks initiated by creep collapse were observed on the outer surface of a f ew test tubes, the cracks did not pass through the tube thickness, and leak tightness was maintained despite a collapse for all tubes tested .