Dynamic response analysis of an onshore LNG-storage tank interaction system subject to impact or earthquake loads

Abstract

Liquefied Natural Gas (LNG) has become an increasingly important element for energy supplies and LNG terminals are planned and built to enable the import and export of LNG from producers to consumers. There are concerns from the communities near LNG terminals about the safety and security of onshore LNG storage tanks under different loads. This paper presents a numerical investigation of the dynamic behaviour of an LNG-tank interaction system subject to impact and earthquake to assess its safety. The coupling system is modelled by a mixed finite element approach where pressure and shell elements are adopted for LNG and the tank wall respectively. The natural characteristics of the dry tank, LNG sloshing in the rigid tank and the coupling system are calculated. The displacement / stress responses of the system are obtained. In the analysis, the multi-layered tank wall is idealised using shell elements with equivalent mechanical properties. An available earthquake data and empirical formula for the impact loads are used. The influence of the fluid-structure interactions is studied for various filling levels of the tank and the different loading conditions. Some conclusions for engineering applications are drawn from the outcome of the simulations