论文标题
理解和增强掉落链的影响引起的张力
Understanding and enhancing the impact-induced tension of a falling chain
论文作者
论文摘要
当掉落的链撞到表面时，它可以比自由落体更快地向下加速。当在撞击表面的链中产生张力时，就会发生这种违反效果。这种张力的大小及其产生的方式取决于所使用的链条类型。对于由水平略微倾斜的杆制成的链，很容易观察到撞击引起的张力。以下报道了在两种不同情况下对这种降链的实验观察结果：当链撞击倾斜的表面以及链的质量密度随着高度的降低时。发现这两种安排都可以增加向下加速度。为了定量描述这些观察结果，开发了理论模型。该模型成功预测了链的位置和速度，即使顶端接近表面，没有任何自由参数。该模型还预测，均匀的杆实际上是产生巨大紧张局势的最佳选择。
When a falling chain strikes a surface, it can accelerate downwards faster than free-fall. This counterintuitive effect occurs when a tension is created in the chain above where it strikes the surface. The size of this tension, and how it is produced, depend on the type of chain used. For a chain made of rods that are slightly tilted from horizontal, the impact-induced tension is readily observable. Here are reported experimental observations on such a falling chain for two different situations: when the chain strikes an inclined surface, and when the chain's mass density decreases with height. It is found that both of these arrangements can increase the downward acceleration. To quantitatively describe these observations a theoretical model is developed. The model successfully predicts the chain's position and velocity, even when the top end approaches the surface, without any free parameters. The model also predicts that uniform rods are practically the best for producing large tensions.
