爆轰冲击载荷作用下射孔段管柱动力响应分析

The dynamic responses of perforated tubular columns under the huge shock waves generated by the detonation process of shaped perforation were analysed by using the finite element modeling and theoretical method in order to provide a basis for the strength and safety analysis of tubular columns. Applying the cantilever beam theory and considering the effect of the column's own weight and axial impact load, a dynamic model of the pipe column was established, and the longitudinal vibration differential equation of the pipe string was derived. The variable separation method was used to solve the natural frequency and main vibration mode of the pipe string. Using the Workbench module, based on the finite element transient dynamics method, the 3D finite element model of a 27/8＂×5.51 mm P110 oil pipe was built. The impact load was measured in situ and the dynamic responses of the pipe string were analyzed. The results show that the relative deviation between the finite element solution and the analytical solution with respect to the natural frequency of the pipe string is 4.18%, which indicates that the finite element method satisfies the accuracy requirement. The displacement, velocity, and acceleration vary with a time period of 15 ms, and at 9 ms, the maximum compression value of the column is 19.15. At 95 ms, the maximum column elongation is 9.1 mm, the free end velocity reaches a maximum of 5.45 m/s, the acceleration reaches a maximum of 2.85 km/s², and the propagation velocity of the stress wave of the column is about 4 930 m/s, which is very close to the theoretical result of 5 123 m. The results provide a basis for theoretically studing the behaviors of slender rods in under water explosion and also give a reference to guide the actual production.