爆轰与聚能射流下射孔枪和套管的应力强度耦合仿真分析

为了探明聚能射孔爆轰冲击载荷下套管的力学性能，在LS-DYNA软件中建立射孔弹-射孔枪-套管三维模型，应用ALE算子分离算法，实现爆轰、药型罩固流转化、侵彻套管和射孔枪的大变形与流固耦合仿真，分析爆轰波叠加对能量、密度、射流速度、套管和射孔枪强度的影响。结果表明，射孔枪射孔孔径为18.7 mm，套管射孔孔径为7.7 mm，穿透射孔枪盲孔过程消耗了大量能量；射孔枪各孔相连125 mm宽带内，最小应力774 MPa，接近材料屈服强度，高爆轰压力作用下发生了“胀枪”；对比单射孔弹射穿套管，3枚射孔弹所用时间减少了8 μs，最大应力增加了260 MPa，并且套管应力值超过材料屈服强度范围(较单枚增加了2.5 mm的圆环)，爆轰重叠区域中心的套管应力也提高了739 MPa，说明爆轰波弹间的叠加加重了对套管的伤害。研究结果为射孔枪安全优化设计和爆轰冲击下套管的力学性能分析提供了技术指导和新思路。

Simulation analysis on the stress intensity coupling of perforating gun and casing under the action of detonation and shaped charge jet

In order to explore the mechanical performance of the casing under the detonation impact load of jet perforating, the 3D model of perforating charge-perforating gun-casing was established using the software LS-DYNA. Then, detonation, fluid-solid transformation of shaped charger liner, large deformation of penetrated casing and perforating charge and fluid-solid coupling were simulated based on the application of ALE operator splitting algorithm. Finally, the effects of the detonation wave superposition on energy, density, efflux velocity, casing and perforating gun intensity were analyzed. It is shown that the perforation diameter of the perforating gun is 18.7 mm, that of the casing is 7.7 mm, indicating that a great amount of energy is consumed in the process of penetrating the blind hole of the perforating gun. In the broad band of 125 mm connecting the holes of perforating gun, the minimum stress is 774 MPa, which is close to the yield strength of the material. It is meant that under the action of high detonation pressure, " bulging gun” happens. Compared with one perforating charge, the casing penetrating time of three perforating charges is 8 μs shorter, its maximum stress is 260 MPa higher, and the excess of the casing stress beyond the yield strength of the material is 2.5 mm ring larger. The casing stress in the center of the detonation superposition area is 739 MPa higher than that of one perforating charge, demonstrating that superposition of detonation wave increases the damage to the casing. The research results provide technical guidance and new ideas for the safety optimization design of perforating gun and the mechanical performance analysis of casing running under detonation impact.