Fregonese Stefano, Bacca Mattia
Mechanical Engineering Department, Institute of Applied Mathematics, School of Biomedical Engineering, University of British Columbia, Vancouver, BC V6T1Z4, Canada.
Soft Matter. 2022 Sep 21;18(36):6882-6887. doi: 10.1039/d2sm00638c.
The mechanics of puncture and soft solid penetration is commonly explored with the assumption of frictionless contact between the needle (penetrator) and the specimen. This leads to the hypothesis of a constant penetration force. Experimental observations, however, report a linear increment of penetration force with needle tip depth. This force increment is due to friction and adhesion, and this paper provides its correlation with the properties of the cut material. Specifically, the force-depth slope depends on the rigidity and toughness of the soft material, the radius of the penetrator and the interfacial properties (friction and adhesion) between the two. We observe that adhesion prevails at relatively low toughness, while friction is dominant at high toughness. Finally, we compare our results with experiments and observe good agreement. Our model provides a valuable tool to predict the evolution of penetration force with depth and to measure the friction and adhesion characteristics at the needle-specimen interface from puncture experiments.
穿刺和软质固体穿透的力学原理通常是在假设针（穿透器）与样本之间无摩擦接触的情况下进行探究的。这导致了穿透力恒定的假设。然而，实验观察报告显示，穿透力随针尖深度呈线性增加。这种力的增加是由于摩擦和粘附作用，本文阐述了其与被切割材料特性的相关性。具体而言，力 - 深度斜率取决于软质材料的刚度和韧性、穿透器的半径以及两者之间的界面特性（摩擦和粘附）。我们观察到，在相对较低的韧性下，粘附起主导作用，而在高韧性时，摩擦占主导。最后，我们将结果与实验进行比较，发现吻合度良好。我们的模型为预测穿透力随深度的变化以及通过穿刺实验测量针 - 样本界面的摩擦和粘附特性提供了一个有价值的工具。
