SHAKEDOWN ANALYSIS OF A CYLINDRICAL VESSEL-NOZZLE INTERSECTION SUBJECTED TO STEADY INTERNAL PRESSURES AND CYCLIC OUT-OF-PLANE BENDING MOMENTS

摘要

In the current research, the shakedown limit loads of a cylindrical vessel-nozzle intersection are determined via a simplified technique. The cylindrical vessel-nozzle intersection is subjected to a spectrum of steady internal pressure magnitudes and cyclic out-of-plane bending moments on the nozzle. The determined shakedown limit loads, forming the shakedown boundary, are utilized to generate the Bree diagram of the cylindrical vessel-nozzle intersection. In addition to the determined shakedown boundary, the Bree diagram includes the maximum moment carrying capacity (limit moments) and the elastic limit loads. The currently generated Bree diagram is compared with previously generated Bree diagram of the same structure, but subjected to in-plane bending. Noticeable differences regarding the magnitudes of the generated shakedown boundaries are observed. Moreover, only failure due to reversed plasticity response occurs upon exceeding the generated shakedown boundary unlike cyclic in-plane bending where the structure experienced both reversed plasticity and ratchetting failure responses. The simplified technique outcomes showed excellent correlation with the results of full elastic-plastic cyclic loading finite element simulations.