Experimental Study And Numerical Simulation Of Thin-walled Cylindrical Shell Under Impact

As a typical thin shell structure,storage tanks are widely used in industrial and agricultural production for the storage of various liquids and solids such as petroleum,liquefied natural gas and grain.In the petrochemical industry,vertical cylindrical floating roof storage tanks are one of the commonly used storage tank forms.In practical applications,in addition to ordinary static and dynamic loads,they are also subjected to accidental loads such as falling rocks or automobile impacts.After the tank is exploded due to accidental load or lightning,operational errors,etc.,debris will be generated to collide with the adjacent storage tank,causing serious damage or even penetration of the storage tank,resulting in continuous explosion accidents which is called domino effect,bringing huge casualties and economic losses.Therefore,it is of great practical significance to study the dynamic response of large steel storage tanks under impact loads.In this paper,the impact tests of the thin-walled cylindrical shell structure are carried out by the drop hammer impact tester.The typical deformation modes of the structure are obtained.After processing the experimental data to obtain the contact force-deformation curve and the absorption energy curve,the curves are analyzed to study the dynamic response characteristics of the cylindrical shell structure under impact and the influence of the height of the cylindrical shell and the height of the drop hammer on the structural responseThe LS-DYNA explicit dynamic finite element software is used to simulate the drop impact test.The reliability of the numerical model is verified by comparison with the experimental results.The stress distribution of the cylindrical shell during the impact process is analyzed.Through the finite element parameter analysis,combined with the experimental results of the specimens that change the impact velocity and the height-to-diameter ratio,the effects of impact velocity,height-to-diameter ratio and diameter-thickness ratio on the dynamic response and failure mode of the structure are studied,and the variation of peak deformation and average force of the structure are obtained;it is found that the failure mode of the cylindrical shell structure changes with the impact velocity and the structure diameter-thickness ratio,but is not affected by the structure height-diameter ratio.The Matlab program is written to simulate the generation and ejection of debris during the explosion of a horizontal cylindrical tank,and the frequency distribution of the mass,impact position,velocity and angle of the conventionally arranged tank when it is hit by the debris from the explosion source is obtained.Taking the large vertical variable wall thick floating roof storage tank in the actual project as the research object,the finite element model including the wind resistance ring and the reinforcement ring is established,and the dynamic response and failure mode of the storage tank under impact are studied through parameter analysis.The effects of debris impact angle,velocity and impact position on the plastic distribution,deformation and wall thickness reduction of the tank are discussed.