Quasi-2D dynamic jamming in cornstarch suspensions: visualization and force measurements
Quasi-2D dynamic jamming in cornstarch suspensions: visualization and force measurements
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DOI：
10.1039/c4sm00864b
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发表时间：
2014-01-01
期刊：
影响因子：
3.4
通讯作者：
Jaeger, Heinrich M.
中科院分区：
文献类型：
--
作者：
Peters, Ivo R.;Jaeger, Heinrich M.
我们报告了在玉米淀粉悬浮液的浮动层中研究干扰前沿的实验。悬架具有接近堵塞的填料分数，在高速撞击时动态变成固体。我们表明，锋面从撞击点向轴向和横向传播，两个传播方向之间的恒定比率约为2。在被卡住的固体内部，我们观察到额外的压缩，这是由于随着固体的增长而增加的应力造成的。在被卡住的固体的初始生长过程中，我们测量的力响应可以完全由增加的质量来解释。只有当干扰锋到达一个边界时，增加的质量才不能再解释测量到的力。然而，我们没有立即看到一个强大的力响应，当我们期望压缩一个卡住的包装。相反，我们观察到推杆上的力响应有延迟，这对应于系统在整个系统中形成接近均匀速度梯度所需的时间。
We report experiments investigating jamming fronts in a floating layer of cornstarch suspension. The suspension has a packing fraction close to jamming, which dynamically turns into a solid when impacted at a high speed. We show that the front propagates in both axial and transverse direction from the point of impact, with a constant ratio between the two directions of propagation of approximately 2. Inside the jammed solid, we observe an additional compression, which results from the increasing stress as the solid grows. During the initial growth of the jammed solid, we measure a force response that can be completely accounted for by added mass. Only once the jamming front reaches a boundary, the added mass cannot account for the measured force anymore. We do not, however, immediately see a strong force response as we would expect when compressing a jammed packing. Instead, we observe a delay in the force response on the pusher, which corresponds to the time it takes for the system to develop a close to uniform velocity gradient that spans the complete system.