Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE, UK.
Cambridge Smart Plastics Ltd, 18 Hurrell Road, Cambridge, CB4 3RH, UK.
Sci Rep. 2023 Jun 20;13(1):10035. doi: 10.1038/s41598-023-37215-9.
The effect of elastomeric damping pads, softening the collision of hard objects, is investigated comparing the reference silicone elastomer and the polydomain nematic liquid crystalline elastomer, which has a far superior internal dissipation mechanism. We specifically focus not just on the energy dissipation, but also on the momentum conservation and transfer during the collision, because the latter determines the force exerted on the target and/or the impactor-and it is the force that does the damage during the short time of an impact, while the energy might be dissipated on a much longer time scale. To better assess the momentum transfer, we compare the collision with a very heavy object and the collision with a comparable mass, when some of the impact momentum is retained in the target receding away from the collision. We also propose a method to estimate the optimal thickness of an elastomer damping pad for minimising the energy in impactor rebound. It has been found that thicker pads introduce a large elastic rebound and the optimal thickness is therefore the thinnest possible pad that does not suffer from mechanical failure. We find good agreement between our estimate of the minimal thickness of the elastomer before the puncture through occurs and the experimental observations.
研究了弹性能量吸收垫的效果，该垫通过软化硬物体的碰撞来实现，比较了参考硅酮弹性体和具有优越内部耗散机制的多畴向列液晶弹性体。我们不仅关注能量耗散，还关注碰撞过程中的动量守恒和传递，因为后者决定了作用在目标和/或撞击物上的力——而正是力在短时间的冲击中造成损害，而能量可能在更长的时间尺度上耗散。为了更好地评估动量传递，我们比较了与非常重的物体的碰撞和与相当质量的物体的碰撞，当一些冲击动量被保留在远离碰撞的目标中时。我们还提出了一种方法来估计用于最小化撞击器回弹能量的弹性阻尼垫的最佳厚度。结果发现，较厚的垫会产生较大的弹性回弹，因此最佳厚度是尽可能薄的垫，而不会发生机械故障。我们发现，我们对弹性体在刺穿发生之前的最小厚度的估计与实验观察结果之间存在很好的一致性。
