论文标题
切割和切片弱固体
Cutting and slicing weak solids
论文作者
论文摘要
如果刀片除了正常的挤压运动，则用锋利的刀将柔软的固体用锋利的固体更快，更光滑。我们用适合软凝胶的一致理论来解释这种常见的观察，并偏离了一个世纪发展的弹性断裂力学的标准理论。当提交超过阈值$σ_1$的压力时，假定凝胶在本地失败。其结构的变化会产生液体层覆盖刀片并通过粘性力传递应力。驾驶参数是武器的比例$ u/w $与刀片的切向速度的比例，以及特征长度$ηW/σ_1$，$η$ the液体的粘度。对于稳定状态的最大值$ u/w $的最大值解释了切入生物学和其他软材料的切向速度的关键作用。
Dicing soft solids with a sharp knife is quicker and smoother if the blade is sliding rapidly parallel to its edge in addition to the normal squeezing motion. We explain this common observation with a consistent theory suited for soft gels and departing from the standard theories of elastic fracture mechanics developed for a century. The gel is assumed to locally fail when submitted to stresses exceeding a threshold $σ_1$. The changes in its structure generate a liquid layer coating the blade and transmitting the stress through viscous forces. The driving parameters are the ratio $U/W$ of the normal to the tangential velocity of the blade, and the characteristic length $ηW/σ_1$, with $η$ the viscosity of the liquid. The existence of a maximal value of $U/W$ for a steady regime explains the crucial role of the tangential velocity for slicing biological and other soft materials.
