Deformation Response Analysis And Detection Method Research For The Shells Of External Floating Roof Tanks

The external floating roof tanks are the important facility and containers that hold national oil and gas resources and chemical materials.Also,the geometric distortion of the external floating roof tanks is an important part of the tank structure integrity detection.Catastrophic failures of the external floating roof tanks such as difficulties in floating roof lifting,steam loss,tank body rupture and leakage caused by excessive geometric distortion will lead to serious accidents,and that maybe cause immeasurable losses to human life safety,peripheral facilities integrity and economic property.Thus,the research on both the damage mechanism of hazardous factors acting on the tank structure and the geometric distortion detection and assessment method of tank shells are of great engineering significance,especially for the prevention and monitoring of safety accidents in the tank area.The main research work of this thesis is carried out as follows:(1)In order to obtain the response characteristics of the external floating roof tanks’distortion behavior subjected to the different load conditions,taking the 100,000m~3large storage tank as the research object,a numerical simulation model based on the finite element theory is constructed to explore the distortion mechanism of storage tank under the both individual and combined action of the wind load,hydraulic pressure and harmonic settlements.The results provide a scientific basis for finding the weak links in the operation of storage tank.(2)In order to obtain the dynamic distortion response characteristics of the external floating roof tank structure subjected to the fluctuating wind load,the fluctuating wind speed spectrum is inputted into the FEA model as the dynamic time-history load.The results of the dynamic time-history analysis are compared with the results of static analysis to derive the transient dynamic distortion characteristics law of the storage tank.(3)Traditional methods exist the drawbacks such as high labor intensity,high danger coefficient and difficulty in comprehensively evaluating the distortion status of tank shells.Thus,a new solution of tank distortion detection based on three-dimensional laser scanning technology is proposed.Also,the detail work flow of tank on-site scanning and data processing is discussed.The feasibility of the solution is verified by a practical case of distortion detection for the scaled model of the 100,000 m~3external floating roof tank.