Elastic-plastic creep buckling analysis of torispherical shell subjected to internal pressure

A torispherical shell is known to buckle with circumferential waves on a knuckle region, when it is subjected to excessive internal pressure. The circumferential waves observed are caused by bifurcation buckling. In the present study, we performed the elastic-plastic creep buckling analysis of a torispherical shell subjected to internal pressure to examine the possibility of the bifurcation buckling mentioned above under the elevated temperature condition where significant creep deformation occurs. The internal pressure close to the bifurcation buckling pressure obtained from a static bifurcation buckling analysis was applied to a torispherical shell in the present analysis. In conclusion, the possibility of the bifurcation creep buckling was denied by the following reasons. (1) The negative circumferential membrane force at a knuckle region which is a trigger for the bifurcation buckling changes to positive due to creep deformation. (2) The plastic zone existing at the time of 0 hr disappears due to the stress redistribution caused by creep deformation. (author)