Numerical Simulation Of Explosion Loading And Dynamic Response Of Steel Tanks

As a special and important type of thin-walled structure, vertical cylindrical steel tanks are widely used for the storage of petroleum, liquefied natural gas (LNG), liquefied petroleum gas (LPG) and other flammable explosive substance. The detonation of these explosives generates high intensity shock wave within a short time, which will not only cause serious damage to storage tank and oil leakage, but also will spread to other adjacent tanks and bring domino-effect fire and explosion accident. The whole process of explosive shock wave acting on tank structure is very complex, which includes the detonation of external condensed explosives and internal flammable gas, the propagation of explosion shock wave, the interaction between shock wave and tank structure. The matching study contains the calculation of explosion shock wave parameters, the determination of explosion loading on tanks, and the dynamic responses of steel tanks.This paper uses numerical simulation methods to study the explosion loading, dynamic responses and failure mechanism of tanks. These researches may provide theoretical basis for the anti-explosion optimization design.Chapter 1 gives a brief introduction to the application development and structure form of steel tanks. The tank explosion accidents at home and abroad are reviewed and the relevant research status is summarized. The main research content of this paper has also been given.Chapter 2 builds up the finite element model to study the distribution of external explosion loading on tanks by employing the software ANSYS/LS-DYNA. On this basis, the simplified model of external explosion loading is presented, which will make a contribution to the analysis of dynamic responses.Chapter 3 respectively makes the coupling and uncoupling simulation to study dynamic responses of tanks under external explosion with the help of the above study and software ANSYS/LS-DYNA. Through the contrastive analysis of the simulation results and computational efficiency, the applicability of coupling and uncoupling method in simulating dynamic responses has been discussed.Chapter 4 adopts the TNT equivalent model to simulate the internal explosion flow field and studies the distribution of explosion loading on tanks under different influencing factors such as height-diameter ratio, TNT equivalent weight, roof forms. Moreover, the fluid-structure coupling effect on explosion loading has also been explored.Chapter 5 establishes a CFD model for simulating explosion flow field in closed containers. Compared with experimental data from existing literatures, the effectiveness and accuracy of the CFD model have been validated. And then on this basis, a series of numerical simulations have been carried out to ascertain the distribution of internal explosion loading on tanks, taking into account the influences of tank capacity, height-to-diameter ratio, roof forms, initial pressure, flammable gas species and concentration.Chapter 6 builds up a two-way fluid-structure coupling model based on ANSYS Workbench, which can simulate the changes of internal explosion flow field in tanks and obtain the structural dynamic response considering the coupling effect. This coupling model contains the CFD model, the CSD model and the System Coupling model for data transmissions. Furthermore, the uncoupling simulation has been adopted to study the dynamic responses of tanks under internal explosion. Through the contrastive analysis of the simulation results and computational efficiency, the applicability of coupling and uncoupling method in simulating dynamic response has also been discussed.Chapter 7 puts forward some optimization measures to lower the explosion loading on tanks based on the above investigation, such as the addition of inert gas, the increase of the underlying oil volume, the rounded arc junctions with reasonable fillet radius and the anti-explosion bands. The effectiveness of these optimization measures has been validated through numerical simulation.Chapter 8 summarizes some important conclusions and indicates some further work on this research topic.