We present new developments to a discrete element model designed to simulate hypervelocity impacts between on-orbit satellites and space debris. The advantage of the discrete element-based simulation method is its ability to accurately model fragmentation which always accompanies a hypervelocity impact event. As previous work showed the model's ability to accurately simulate hypervelocity impact fragmentation at very high impact velocities, our focus in this paper is predominantly on improving the model's behavior at lower velocities. These low-velocity secondary-impacts also play an important role in determining the final distribution of fragments following a hypervelocity impact event. We achieve this by enhancing our discrete element model's bonding structure to more accurately simulate a continuum material. We evaluate the enhanced model's performance with a variety of simulations ranging from tension tests to hypervelocity impacts. Parameters for the model are calibrated for the whole range of impact velocities using well know ballistic limit equations. Three large impact simulations are presented which demonstrate the model's capabilities in capturing the full range of fragment sizes. The satellite breakup simulation results are compared to the NASA breakup model and show very good agreement.

我们展示了离散元模型的新进展，该模型旨在模拟在轨卫星和空间碎片之间的超高速撞击。基于离散元素的模拟方法的优势在于它能够准确地模拟始终伴随超高速撞击事件的碎片。由于先前的工作表明该模型能够在非常高的撞击速度下准确模拟超高速撞击碎片，因此我们在本文中的重点主要是改善模型在较低速度下的行为。这些低速二次撞击在确定超高速撞击事件后碎片的最终分布方面也起着重要作用。我们通过增强离散元素模型的粘合结构来更准确地模拟连续材料来实现这一点。我们通过从张力测试到超高速撞击的各种模拟来评估增强模型的性能。使用众所周知的弹道极限方程对整个冲击速度范围内的模型参数进行校准。展示了三个大型撞击模拟，展示了该模型在捕获所有碎片尺寸方面的能力。卫星解体模拟结果与 NASA 解体模型进行了比较，显示出非常好的一致性。s 捕获所有片段大小的能力。卫星解体模拟结果与 NASA 解体模型进行了比较，显示出非常好的一致性。s 捕获所有片段大小的能力。卫星解体模拟结果与 NASA 解体模型进行了比较，显示出非常好的一致性。