Impact phenomena shaped our solar system. From the accretion of the planetesimals 4.6 billion years ago to the comparatively recent spallations of meteorites from their parent bodies, which take them to Earth, this ceaseless process has left no bit of solid matter untouched. As usual for most solar system processes, the scales are far different than we can address directly in the laboratory. Impact velocities are often much higher than we can achieve, sizes are often vastly larger, and most impacts take place in an environment where the only gravitational force is self-gravity. Laboratory studies, by contrast, are limited to disruptive impacts with typical velocities $sim$3 km/s, involving targets smaller than a kilogram in an imposed terrestrial gravitational environment. We must extrapolate from these data by twenty orders of magnitude before we reach the mass range of asteroids, comets and planetesimals.;The complexity of fragmentation phenomena, and the role both strength and gravity play in most interesting catastrophic impacts, make numerical models of catastrophic disruption the most viable research tools. But numerical models must be subject to careful scrutiny regarding numerical accuracy and the proper representation of physics. For this reason two very different code models of fragmentation and catastrophic disruption are presented here. They not only are both good predictors of laboratory outcomes, but they also largely agree about predictions involving large-scale extrapolation. A simple analytical model for fragment size distributions in the strength regime is also presented. Each of these models is suited to a particular class of problem, depending on the complexity and the sophistication required. It is hoped that the ideas and models developed in these pages will contribute to a better understanding of fracture and fragmentation events with regard to the evolution of solar systems and planets.
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机译：撞击现象影响了我们的太阳系。从46亿年前的小行星的生长到其母体将陨石带到地球的相对较新的陨石剥落，这一不断的过程几乎没有触及任何固体物质。与大多数太阳系过程一样，比例尺与我们在实验室中可以直接处理的比例相差很大。冲击速度通常比我们能达到的要高得多，尺寸通常要大得多，并且大多数冲击发生在唯一引力是自重的环境中。相比之下，实验室研究仅限于破坏性影响，典型速度为sim $ 3 km / s，涉及的目标在施加的地球引力环境中小于一千克。在到达小行星，彗星和小行星的质量范围之前，我们必须从这些数据中推断出二十个数量级。破碎现象的复杂性以及强度和重力在最有趣的灾难性影响中的作用，使灾难性数值模型成为可能破坏最可行的研究工具。但是，数值模型必须经过严格的仔细检查，以确保数值准确性和物理的正确表示。因此，此处介绍了两个非常不同的碎片和灾难性破坏代码模型。它们不仅是实验室结果的良好预测指标，而且在很大程度上涉及涉及大规模外推的预测。还提出了强度范围内碎片尺寸分布的简单分析模型。这些模型中的每一个都适合特定类别的问题，具体取决于所需的复杂性和复杂性。希望这些页面中开发的思想和模型将有助于更好地理解关于太阳系和行星演化的破裂和破碎事件。
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