Celebi Hasan F, Andrews Austin J, Pothos Ioannis, Bellefeuille Nathan A, Olson Bernard A, Schwartzentruber Thomas E, Hogan Christopher J
Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455, USA.
Department of Aerospace Engineering and Mechanics, University of Minnesota, Minneapolis, MN 55455, USA.
Sci Adv. 2025 Aug 22;11(34):eadx0294. doi: 10.1126/sciadv.adx0294. Epub 2025 Aug 20.
Complex crater formation is an incompletely understood phenomenon, referring to instances wherein a high-speed projectile impacts a surface and leaves a crater characterized by a central uplift. We elucidate the mechanism of complex crater formation by examining crater formation on different polymer substrates resulting from microparticle impacts with tunable microparticle diameter (1.8 to 6.1 micrometers) and impact velocities up to 840 meters per second. Central uplift is uniquely observed in craters on amorphous polymers, with the degree of complexity directly linked to the polymer thermal properties and homogeneity. We demonstrate that the complex crater volume scales with the ratio of the specific kinetic energy of the impacting object to the specific energy required to raise the impacted substrate to its glass transition temperature (the Eckert number). Our results also confirm that complex crater formation can occur not only for macroscopic celestial collisions but also during sufficiently high velocity collisions at the micrometer scale.
复杂撞击坑形成是一种尚未完全理解的现象，指的是高速抛射体撞击表面并留下以中央隆起为特征的撞击坑的情况。我们通过研究不同聚合物基底上的撞击坑形成来阐明复杂撞击坑形成的机制，这些撞击坑是由直径可调（1.8至6.1微米）的微粒以高达840米每秒的撞击速度撞击产生的。在无定形聚合物上的撞击坑中独特地观察到中央隆起，其复杂程度与聚合物的热性能和均匀性直接相关。我们证明，复杂撞击坑的体积与撞击物体的比动能与将被撞击基底提升至其玻璃化转变温度所需的比能量之比（埃克特数）成比例。我们的结果还证实，复杂撞击坑形成不仅可能发生在宏观天体碰撞中，也可能发生在微米尺度的足够高速碰撞期间。
