爆炸与火荷载联合作用下充液压力圆管结构的多场耦合损伤效应研究

The potential risks of oil and gas pipelines subjected to military strike and terrorist attack are increasing. The damage of the pipeline subjected to combined actions of blast and fire is a major issues which is related to the safety of national lifeline and a frontier topics need to be investigated urgently in the field of disaster prevention and mitigation engineering. Liquid-filled pressure circular tube structure can simulate oil and gas pipeline effectively, so the studies of multi-field coupling damage effects of liquid-filled pressure circular tube under the combined actions of blast and fire loading has realistic application background. Combined methods of theoretical analysis, numerical simulation and model experiments will be conducted in this project. Taking account of the coupling effects of strain rate and temperature, the constitutive model of X70/X80 steel material will be established. An explicit-implicit coupling numerical calculation model and efficient theoretical analysis model of dynamic response of circular tube structure under the combined effects of blast and fire loading will be established. The pressure field-temperature field-interior fluid field coupling damage and failure mechanism will be revealed, and the influence laws of blast and fire loading, fluid filled pre-pressure, material and structure size characteristics on the damage effects will be clarified. The project will also establish a comprehensive damage assessment method based on P-I-T curved surface, and finally a computing platform for predicting and evaluating the damage effects of oil and gas pipeline will be transformed. The results have important significance theoretical and engineering value for safety assessment and disaster prevention design calculation of pipelines.

油气管道能源动脉遭受军事打击及恐怖袭击的潜在风险日益增大，其在爆炸与火灾联合作用下的损伤破坏是涉及国家生命线工程安全的重大问题，是防灾减灾工程领域亟需研究的前沿课题。充液压力圆管结构可有效模拟油气管道，针对其研究爆炸与火荷载联合作用下的多场耦合损伤效应具有重要现实背景。本项目拟采用数值模拟、理论分析及模型实验研究手段，推演构建耦合应变率及温度效应的管道钢材料本构模型，建立爆炸与火荷载联合作用下圆管结构动态响应的显隐式耦合精细化数值计算模型和高效理论分析数理模型，揭示圆管结构在动压力场-温度场-内流场多场耦合作用下的损伤内在机理，理清爆炸与火荷载加载条件、充液预加内压、结构材料与尺寸特性等关键因素对损伤效应的影响规律。建立基于P-I-T曲面的爆炸与火荷载综合损伤效应评估方法，并最终转化为实际油气管道的损伤预测与评估平台。项目成果对于管道安全性评估、防灾设计具有重要理论指导意义和工程应用价值。

油气管道遭受军事打击及恐怖袭击的潜在风险日益增大，其在爆炸与火灾联合作用下的损伤破坏是涉及国家生命线工程安全的重大问题，是防灾减灾工程领域亟需研究的前沿课题。研究爆炸与火荷载联合作用下圆管结构的多场耦合损伤效应具有重要现实背景。本项目采用模型实验、数值模拟及理论分析相结合的方法，重点开展了应变率及温度耦合作用下金属材料力学行为及本构关系模型、火与爆炸荷载联合加载实验平台设计及测试系统构建、受火金属圆管结构温度分布特性、火与爆炸荷载联合作用下金属圆管损伤效应机理及评估等研究工作。. 本项目系统开展了温度与应变率耦合条件下金属材料的静动态力学性能实验，建立了考虑温度和应变率耦合效应的修正J-C本构关系模型；构建了铠装热电偶集群与红外热成像仪组成的互补式圆管温度测试系统，研发设计了由起爆控制系统、装药固定及传送装置、火荷载发生装置等单元组成的火与爆炸荷载联合加载实验专用平台；系统实施了火与爆炸荷载联合加载下金属圆管结构损伤响应试验及数值模拟，获得了不同工况条件下的宏观变形损伤特征及失效模式，理清了爆炸与火荷载加载条件、结构材料与尺寸特性等重要因素对圆管宏观损伤效应的影响规律。针对圆管损伤变形部位的微观组织及形貌进行了探析，实现了从宏观损伤变形特征到微观机理分析方法的耦合；基于能量吸收原理并通过定义能量比率定量研究了圆管塑性变形区域对爆炸能量吸收情况，并基于刚塑性材料假设及Tresca精确屈服函数建立了圆管塑性损伤的理论分析模型，得到了圆管壳体中部挠度的计算公式，获得了圆管壳体塑性铰形成和移动规律；构建了圆管损伤特征值与爆炸比例距离及温度的空间拟合曲面，引入B-R动态屈曲判别准则并建立了考虑结构整体挠度影响因素下的损伤效应评估方法。. 本项目研究成果可为准确评价、分析在役油气管道结构的安全性和制定防灾减灾技术措施提供重要理论支撑及技术支持，具有重大理论指导意义和工程应用价值。