爆炸容器内冲击波系演化及壳体响应的数值研究

对中心装药爆炸后冲击波的产生、传播和壳体动态响应全过程进行了数值研究。认为RDX瞬时爆炸 ,爆炸近场采用自相似解 ;冲击波传播和波系演化采用PPM (the Piecewise Parabolic Method)格式求解Eu ler方程 ;壳体响应采用有限元方法求解拉氏坐标系下由虚功原理得到的动力学方程。壳体内壁面边界条件分别采用强耦合和弱耦合方法处理。结果表明 :(1)当装药量相同时 ,薄壁壳体振型比厚壁壳体复杂得多 ,振幅也大 ;(2 )当装药量不同 ,壳体厚度相同时 ,爆炸场冲击波的演化过程不同 ;(3)对少量装药 ,产生的冲击波强度低 ,壳体变形小 ,是否考虑内边界运动 ,对计算结果的影响不大 ;(4 )在本文条件下 ,爆炸容器封头顶点所受的载荷最大 ,是最易发生破坏的地方 ,侧壁与爆点所在横截面的交线 ,也易破坏。

Numerical investigation on blast wave propagation and dynamic response of an explosion vessel

Numerical simulations were conducted to study dynamic response, blast wave generation and propagation within an explosion vessel. Assuming the high explosive ignited spontaneously, a self similar solution was exploited to describe the shock generation in a point explosion field. The axisymmetric Eulerian equations were solved by the PPM(the Piecewise Parabolic Method) scheme in order to capture the blast wave propagation and reflection in the vessel. The coupling wall conditions were described by two methods,namely,the strong method and the weak method.The results, which are in fairyly agreement with the experimental results, consist mainly of the pressure contours, velocity fields, displacement contours of shell deformation and pressure history at the specified points along the inner wall surface, and indicate that: (1) in the case of same charge of explosive, the vibration altitude and mode of a thin shell are much more complex than those of a thick one, (2) if the shell thickness remains unchanged, the blast wave structure varies much according to the charge of explosives, and (3) with the small charge of explosive, the strength of blast wave and shell deformation are also small, which do not change much with or without the moving of inner wall. Also calculations show that fatigues always appear at vessel peaks and points nearest to the charge center.