空间碎片超高速碰撞数值模拟的SPH方法

利用光滑质点动力学SPH(Smoothed Particle Hydrodynamics)方法对Whipple防护结构在空间碎片超高速碰撞下的物理过程进行了数值模拟.在数值模拟中,为了充分发挥SPH方法和有限元方法FEM(Finite Element Method)的优点,利用有限元单元和SPH节点混合建模,将有限元单元和SPH节点(SPH nodes)通过定义接触条件相结合,在大变形和飞溅区域采用SPH节点建模,而小变形区域则采用有限元单元建模,从而大大节省求解时间,提高计算效率.计算结果表明,弹丸在穿透前板后,形成二次碎片,碎片云经膨胀和拉长,对后板造成轻微的损伤,这和文献的相关试验数据是符合的.利用SPH方法对空间碎片的超高速碰撞过程进行数值模拟,不仅很好地预测了Whipple防护结构的破坏情况,而且对整个碰撞过程,包括碎片云的形成、膨胀和拉长过程都有形象的描述,符合超高速碰撞的试验测试结果.

Numerical simulation of space debris hypervelocity impact using SPH method

The SPH(smoothed particle hydrodynamics) was applied to simulate the problems in Whipple structure hypervelocity impact. In modeling the structure, the SPH and FEM(finite element method) discretizations were used simultaneously to reduce the CPU time, and this was very convenient and advantageous in practical engineering design when more CPU time consuming. SPH nodes were employed to model the area where the deformation was larger and likely to be perforated by the projectile. FEM nodes were employed to model the area with small deformation. The calculation results indicate that the fist bumper was perforated and the main wall cratered. Those results were compared with the test results from the literature and indicated fairly good agreement with each other. It demonstrates that SPH method is helpful and efficient in understanding the hypervelocity impact phenomena and fracture mechanism in the space debris hypervelocity impact problem.