• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Nature >Impact-activated solidification of dense suspensions via dynamic jamming fronts
【24h】

Impact-activated solidification of dense suspensions via dynamic jamming fronts

机译：通过动态卡纸前端进行冲击激活的致密悬浮液固化

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Although liquids typically flow around intruding objects, a counterintuitive phenomenon occurs in dense suspensions of micrometre-sized particles: they become liquid-like when perturbed lightly, but harden when driven strongly. Rheological experiments have investigated how such thickening arises under shear, and linked it to hydrodynamic interactions or granular dilation. However, neither of these mechanisms alone can explain the ability of suspensions to generate very large, positive normal stresses under impact. To illustrate the phenomenon, such stresses can be large enough to allow a person to run across a suspension without sinking, and far exceed the upper limit observed under shear or extension. Here we show that these stresses originate from an impact-generated solidification front that transforms an initially compressible particle matrix into a rapidly growing jammed region, ultimately leading to extraordinary amounts of momentum absorption. Using high-speed videography, embedded force sensing and X-ray imaging, we capture the detailed dynamics of this process as it decelerates a metal rod hitting a suspension of cornflour (cornstarch) in water. We develop a model for the dynamic solidification and its effect on the surrounding suspension that reproduces the observed behaviour quantitatively. Our findings suggest that prior interpretations of the impact resistance as dominated by shear thickening need to be revisited.
机译：尽管液体通常会在侵入的物体周围流动，但在微米级颗粒的密集悬浮液中会发生违反直觉的现象：当受到轻微干扰时，它们会变成液体状，但在强烈驱动下会变硬。流变实验研究了这种增稠在剪切作用下如何产生，并将其与流体动力相互作用或颗粒膨胀联系在一起。但是，仅靠这两种机制都不能解释悬架在撞击下产生非常大的正法向应力的能力。为了说明这种现象，这样的应力可能足够大，以使人可以跨过悬架而不会下沉，并且远远超过在剪切或拉伸下观察到的上限。在这里，我们显示出这些应力来自于冲击产生的凝固前沿，该凝固前沿将最初可压缩的粒子矩阵转换为快速增长的堵塞区域，最终导致动量吸收异常。使用高速摄影，嵌入式力感测和X射线成像，我们捕获了此过程的详细动态，因为它使金属棒减速，使其撞到水中的玉米粉（玉米淀粉）悬浮液。我们为动态凝固及其对周围悬浮液的影响开发了一个模型，该模型定量地再现了观察到的行为。我们的发现表明，需要重新研究以剪切增稠为主的抗冲击性。

著录项

  • 来源
    《Nature》 |2012年第7406期|p.205-209|共5页
  • 作者

    Scott R. Waitukaitis; Heinrich M. Jaeger;

  • 作者单位

    James Franck Institute and Department of Physics, The University of Chicago, Chicago, Illinois 60637, USA;

    James Franck Institute and Department of Physics, The University of Chicago, Chicago, Illinois 60637, USA;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号