Dynamic Response Analysis And Safety Evaluation Of Oil And Gas Pipeline Under Explosive Impact Loading

For a long time, researchers studied the numerous factors of oil and gas pipeline failure, but they neglect the influence factor from blast loads, this also led to an increasing number of pipeline disasters which has caused by blast loads in recent years. The cause of blast loads is widespread, mainly includes:blasting construction near the oil and gas pipeline, vapor cloud explosion caused by parallel pipeline leakage, war and other accidental factors etc. The existing on the blast loads and pipeline response research focused on the oil and gas pipeline dynamic characteristics when explosive explode and propagate in a single medium, however, the research of the oil and gas pipeline dynamic characteristics when explosive explode and propagate in the coupling medium is almost blank, the research of vapor cloud explosive blast caused by parallel pipeline leakage carried out less.In this paper, the research mainly included vapor cloud explosive blast caused by parallel suspended pipeline leakage and the dynamic response of buried gas pipeline under the impact of blast loads in air&soil medium. The LS-DYNA finite element program combined with the existing experimental data and analytical method are made use of to verify the reliability of the explosion simulation under in air or soil. Matlab and LS-DYNA are combined with a practical example to simulate and evaluate the impact of vapor cloud explosion caused by parallel suspended pipeline leakage. LS-DYNA are combined with a practical example to simulate and evaluate the dynamic response of buried gas pipeline under the impact of blast loads in air&soil medium. VB language is used to develop the evaluation system for example. Through further analysis we get the following conclusions:(1) The simulation calculation method in the text is reasonable to study explosives blast in the specified medium, design of the finite element model, algorithm, boundary conditions and material parameters is reliable;(2) Vapor cloud explosive blast caused by parallel suspended pipeline leakage could damage the complete pipeline serious, pipeline parallel spacing is smaller more serious destruction, pipeline pressure is higher, the more obvious damage. Pipe stiffness criterion and strength criterion compared too conservative. Plume model which is used to calculate the pore diffusion is feasible. There are many assumptions about TNT equivalent method, reduced error of TNT equivalent method is large and difficult to avoid. But the method can meet the requirements of used for general engineering site assessment;(3) Simulation of the dynamic response of buried gas pipeline under blast loads in air&soil medium can be realized. The dynamic response of the index from the key position of the pipeline is the most obvious, these places are the weak point of pipeline strength and stiffness. Effect of the change in the distance between the pipeline and the explosive and quality of explosive is greater than change of two other factors to the dynamic response of the pipeline, and the strength of pipeline is severe attenuation in the early stage, but in the late, the change in strength of pipeline is relatively flat; (4) The calculation deviation of the pipeline evaluation system under the impact of blast loads is determined by the explosion theory and the quality of model database of existing, the present stage is reasonable. The evaluation system can satisfy the application part of the project at the present stage, this system has a big upgrade space, and function and algorithm within the system could be applied to the same type of the model system.Finally, the research work is summarized, the research direction in the future is prospected.