Research Of Oil And Gas Pipelines Under Blast Loads With Numerical Simulation Method

Oil and gas pipelines which are easily damaged leading to oil and gas leakage are widely used in the industrial sectors.Oil and gas pipelines might be damaged by many reasons such as worldwide terrorist attacks,blasting construction near pipeline,gas leakage of parallel pipelines leading to gas cloud explosion and other accidental factors.Researches in regard to existing oil and gas pipelines by explosion which are usually blank mainly focus on dynamic response in a single medium,while blasting shock wave propagating in a variety of media,subsea pipelines in the running state suffered by blast loading and gas leakage of parallel pipelines leading to gas cloud explosion researches less.The numerical simulation method is used in the paper,with the aid of numerical calculation software Matlab and General FEM LS-DYNA.Firstly,the effects of deformation and failure under contact explosion wound be studied,aiming to analyze the reliability of the simulation method.Secondly,combined with actual example,the simulation evaluation wound be used to subsea pipe under blasting loads.Thirdly,Gaussian plume model wound be adopted to analyze gas leakage of pipeline and diffusion area.Finally,TNT equivalent method wound be introduced to convert gas to TNT which combines the diffusion of leakage with explosive shock,and then simulate the dynamic response of the gas cloud explosive shock.The results show that,local destructive characteristics caused by contact explosion on the pipeline,especially the area of pipeline near the explosive damages worse which has a petaloid rupture and produces high-speed projectile fragments are obvious and the results show that the reliability of numerical simulation method is proved;The results of simulation of the impact of shallow sea pipeline sufferd by the explosion show that anti-explosive ability of pipeline in the running state is better than which of blank pipeline,while buried pipeline is better than bare pipeline,so shallow pipeline needs to be buried laying and the internal pressure of pipeline which is shutdown should also be appropriate to maintain to improve safety;It will cause fatal damage to the pipelines if the distance between parallel pipelines is greater than 6m which is confirmed by LS-DYNA simulation,and the explosion impact theory can provide the basis for the pipeline safety assessment compared with the existing standard which adopts 10 m as safety distance;It is more conservative elliptical design criteria for stiffness determination than the strength criterion which can be used to analyze safety assessment of pipelines under the action of explosion load.