Dynamic Stress Analysis of Multilayered Structure With Radial Gaps of Cylindrical Pressure Vessel Under Plane Strain Conditions

Radial gaps were found in multilayered cylindrical vessels which experience inner explosion accidents in chemical plants in the past few years worldwide. It is necessary to investigate the dynamic response of multilayered structures with radial gaps to ensure the vessel safety. This paper presented a numerical modeling of the dynamic response of a multilayered structure with radial gaps of cylindrical pressure vessel under plane strain conditions by using the ANSYS/ls-dyna package. The effects of the dynamic loading profile and the radial gap height are considered in the investigation. The stress spatial distribution, the stress and the plastic deformation variation curves with time are emphatically analyzed. The results show that the stress variation of the entire loading process can be divided into four stages: the oscillation stage, the yield stage, the fast increase stage, and the redistribution stage. The layer stress distributes discontinuously at the gaps between layers and distributes unevenly in any single layer. The inner layer stress is not always larger than the outer layers' during the whole loading process. The effect of loading profile on the dynamic response is not as obvious as the gap height. As the gap height increases, the stress oscillation stage is suppressed and becomes shorter. While the loading recovers to the operation pressure, the stress and the plastic deformation of inner layers increases and vice versa for the outer layers.