Finite Element Study On Mechanical Behavior Of LNG Storage Tank’s Outer Wall Under Impact Loading

Steady increases in both global energy consumption and awareness in prevention of environment pollution highlight the great value of clean energy. Liquefied natural gas(LNG) is a popular clean energy, which is mostly stored in specific tanks. T he largest volume of LNG storage tank in China could easily reach 200,000 m3. However, as LNG is flammable and explosive, the explosion is foreseen when the LNG storage tank is impacted by some flying objects which will cause significant casualties, loss in properties and may bring about many potential secondary disasters. I t is, therefore, of great importance to study the mechanical behavior of LNG storage tank under impact loading.In this paper, the following research work has been performed in order to fully investigate the dynamic responses of outer wall of the LNG storage tank under impact loading.(1) Finite element model(FEM) for an ogival-nosed projectile to penetrate into reinforced concrete slabs was built by means of computer-aided engineering program ANSYS/LS-DYNA, and suitable constitutive models were selected for simulation purpose. The simulation results and experiment data were compared to verify the feasibility of the FEM as well as its constitutive relation.(2) Falling-weight impact tests on scale model of LNG storage tank’s dome were carried out and a brief analysis was given. The test was additionally sim ulated and compared with the experimental data in order to verify the parameters used in the constitutive model.(3) A missile and 160,000 m3 storage tank model was established using ANSYS/LS-DYNA program to investigate the damage of LNG storage tank under the missile impact. The results indicated that only the areas around the missile impact point were seriously damaged, while the whole tank remained intact.(4) Simulation in elastic bars impact was performed to verify the feasibility and precision of ADINA program used to solve the impact issue. The reliability of ADINA program was further verified in several aspects by comparing the results obtained with FEM using ADINA and ANSYS/LS-DYNA.(5) The effects of several factors on the mechanical behaviors of LNG storage tank under impact loading were investigated using FEM model. The results showed that, under the equal conditions, 1) the destruction degree of LNG storage tank’s outer wall increased with the increase of missile’s quality and the initial velocit y; 2) the change of outer wall reinforcement ratio had no significant impact on results; 3) the impact-resistant capacity of storage tank could be increased significantly by improving the concrete strength grade.