基于SPH-FEM耦合算法的埋地输气管道近场爆炸冲击动力响应

Impact dynamic response of near-field explosion in buried gas pipeline based on SPH-FEM coupling algorithm

利用ANSYS/LS-DYNA和LS-PREPOST前后处理模块,建立基于光滑粒子流体力学-有限单元法(SPH-FEM)耦合的土中爆炸模型。结果表明,土中爆炸波峰值压力随比例爆距的衰减规律与经验曲线基本一致,且瞬时爆腔尺寸也和相关经验描述吻合较好,从而验证了方法的可行性与准确性。针对X80大口径高压输气管线在土中近场爆炸的冲击响应过程,建立管-土-炸药耦合模型,分析起爆后不同时刻爆腔形状的演变过程(从球状到椭球状),得到不同时刻管体扰动(变形与受力)与土壤介质压缩形态的内在联系,详细描述管体迎爆面、背爆面测点的位移及应力特征,并反映最大冲击应力的截面分布情况及其在不同时刻的出现位置,最后,基于应变极限判断受冲击管道的失效情况。研究采用的耦合算法可为管道防爆研究提供新思路,对爆炸灾害下管体及周边结构的风险评估提供基于模拟分析的定量依据。

Pre-post processing modules of ANSYS/LS-DYNA and LS-PREPOST were used to establish the in-soil explosion model based on the coupling between smoothed particle hydrodynamics and finite element method（SPH-FEM）.The results show that the attenuation law of in-soil explosion peak pressure with proportional blasting distance is basically consistent with the empirical curve,and the instantaneous blasting cavity size also accords well with relevant empirical description,so as to prove the feasibility and veracity of this method.Aiming at the impact response process of in-soil near-field explosion in X80 large-diameter high-pressure gas transmission pipeline,the pipe-soil-explosive coupling model was established to analyze the evolution processes of blasting cavity shape（from globular to axiolitic）at different moments posterior to explosion.As a result,the inner relations between pipeline body disturbance（deformation and stress）and soil medium compression form at different moments were obtained to detailedly describe the displacement and stress characteristics of measuring points on the front-back blasting surfaces of pipeline body as well as reflect the section distribution and location of maximum impact stress at different moments.Finally,the failure conditions of impacted pipeline were estimated based on strain limit.The coupling algorithm was used in this study for applying new ideas to pipeline anti-explosion research,which also provided the quantitate basis based on simulation analysis for the risk evaluation of pipeline body and surrounding structures under explosion disaster.