Numerical Simulation Of Explosion Prediction And Dynamic Response Of Arched Tanks Under Pool Fire

With the development of Chinese economy,the demand for oil and the stock of reserves continue to grow.Vertical vault storage tanks are one of the most common tank types.When the oil storage tank is in a pool fire environment,the temperature of the tank wall rises rapidly under the baking of the flame,and the strength of the tank decreases as the temperature increases.In the tank,as the oil continuously evaporates at high temperatures,the pressure is continuously increased,and the strength of the tank material is lowered,and the tank is in danger of exploding.Once an oil tank is exploded,it will cause certain damage or impact to rescuers,current equipment and other oil storage tanks.The tank body is welded by a plurality of bent steel plates,and the weld bead strength has an important influence on the strength of the tank.In particular,in order to reduce the degree of explosion hazard,the upper top weakened weld is the ultimate limit of the tank explosion.Therefore,the finite element calculation and reliability analysis of the oil tank explosion are carried out under the pool fire scene,it is important to quantify the damage mechanism of the weakened weld at the top of the tank.In this paper,the thermal-elastic coupled finite element calculation of the vertical storage tank in the pool fire scene is carried out.Based on the reliability theory,the quantitative reliability sensitivity analysis of fire heat source process parameters,tank structure size parameters and storage tank physical parameters was carried out.The microcrystalline finite element calculation of the weld at the "weak joint structure" of the storage tank reveals the high temperature explosion plastic deformation process and the thermal fatigue failure accumulation mechanism.Tensile test failure experiments at different temperatures is carried out on the tank welds,which verifier the reliability of the finite element calculation model.The specific work includes:(1)Establishing a three-dimensional finite element model of a vertical vault tank including a "weak joint structure" weld.According to the actual working conditions,the load conditions of the tank body weight,oil storage hydraulic pressure,saturated vapor pressure,heat convection and heat radiation are applied,and the thermal elastic coupling finite element calculation of the storage tank is performed.The thermal stress and strain distribution cloud map of the tank under the pool fire scene is obtained;(2)Using the PDS probability calculation module,based on the Monte Carlo method,the reliability sensitivity of the tank thermal-structural parameters in the pool fire scenario is evaluated,and the degree of influence of different parameters on thetank destruction in the pool fire scenario is quantified;(3)The tensile test at different temperatures of the "weak joint structure" of the oil storage tank is carried out,and the simulation results are compared with the experimental data to verify the validity of the finite element calculation model;(4)The micro-crystal finite element calculation of the weld is carried out,and the microstructure change during the buckling plasticity process is obtained,which reveals the micro-plastic deformation behavior and failure mechanism of the tank weld pool fire scene;(5)Based on the thermal-elastic coupling finite element calculation and analysis of the storage tank in the pool fire scene,the N-code software is used to analyze the thermal fatigue of the oil storage tank under high temperature,and the overall damage and life of the oil storage tank are obtained.