基于率型损伤演化与流固耦合的内爆炸下管道裂纹动态扩展机理与预测研究

Recent years, the occurrence of serious explosion accidents (Qingdao oil, Tianjin harbor) and the safety design of explosion containment vessels (ECVs) and pulse detonation engines (PDEs) highlight the importance to the study of the mechanism and prediction of structural crack propagation under explosive loading. In this project, based on the thermally activated mechanism of metal dislocation and adiabatic shear theory, combined with SHPB experiments with a wide range of strain rates, a rate-dependent damage evolution law coupled with thermo-viscoplastic constitutive model will be established. A simplified detonation modeling algorithm ignoring the detailed reaction mechanism will be proposed based on the CJ detonation theory. Then a fluid-structure coupling simulation technic with the capability to cope with structural fracture and explosion reaction will be developed based on the ALE spatial discrete method and the penalty function contact algorithm. Based on above, the numerical analysis model for dynamic crack propagation of pipe under internal explosion will be established to study the stress-strain and energy transfer at the crack tip and to clarify the interaction and relationship between the material failure mode and crack propagation behavior. The dynamic crack propagation (curving, bifurcation) mechanism will be revealed and an effective method to analyze and predict the dynamic crack propagation of pipe under internal explosion will be established. Above research can provide theoretical basis for the safety design of explosively loaded structures and the risk assessment of confined explosions.

近年来重大爆炸事故（青岛输油、天津港）的发生以及国防军工领域抗爆容器、脉冲爆震发动机（PDE）的安全设计均凸显了爆炸载荷下结构裂纹扩展机理及预测研究的重要性。本项目拟基于金属位错的热激活运动机制与绝热剪切理论，结合宽应变率范围内材料SHPB实验，建立应变率依赖的（率型）损伤动态演化率并耦合材料热黏塑性本构模型；根据CJ爆轰理论提出一种忽略详细化学反应机理的简化爆轰模拟算法，进而基于ALE离散方法与罚函数接触算法发展计及固体断裂与爆炸化学反应的流固耦合模拟算法；以此为基础，构建内爆炸下管道裂纹动态扩展数值分析模型，探究裂尖应力应变及能量变化转移规律，阐明管道失效模式与裂纹扩展行为间的相互作用及影响关系，进而揭示裂纹动态扩展（弯折、分叉）机理，并建立有效的内爆炸下管道裂纹动态扩展数值分析与预测方法。上述研究可为承受爆炸载荷结构的安全设计及受限空间爆炸风险评价奠定理论基础。

本项目面向极端条件下承压结构耦合损伤及失效预测重要需求，围绕“高应变率下材料动态损伤演化及其与本构耦合”、“爆炸载荷下管道裂纹动态扩展机制”两个关键问题，开展了内爆炸下管道裂纹动态扩展机制与预测研究。主要研究内容如下：1）基于绝热剪切带演化的率-温等效效应和位错的热激活运动机制，推导了率型损伤动态演化率，建立了适用于高应变率加载条件的耦合率型损伤演化的热黏塑性本构模型；2）结合CJ爆轰理论、任意拉格朗日-欧拉（ALE）算法和罚函数接触算法，发展了计及固体断裂与爆炸化学反应的流固耦合数值模拟方法；3）构建了内爆炸下管道裂纹动态扩展分析与预测模型，裂纹扩展行为及管道断裂形貌预测结果相比国内外公开文献与典型实验具有更好一致性，在此基础上提出了耦合结构失效模式的管道爆炸后果预测与评估方法；4）阐明了管道裂纹渐进式动态扩展实际上是轴向传播弯曲波与裂纹尖端相互作用结果这一物理机制，揭示了内爆载荷特征参数（载荷速率）与裂纹周期渐进扩展长度间的内禀关系，进而提出了基于断面痕迹分析的管道爆炸强度与类型推演新方法。研究在International Journal of Impact Engineering、International Journal of Hydrogen、压力容器（机械工程T1）等本领域权威期刊发表论文5篇，其中SCI论文4篇；申请/授权国家发明专利4项、美国专利1项；项目负责人获第10届中国压力容器优秀青年论文一等奖（2名/4年）；在国际结构完整性会议（ISSI）、全国压力容器学术会议、材料与结构强度青年论坛等国内外会议上作报告/墙报展示4次；培养毕业硕士研究生1名，另有3名硕士研究生在读。