Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, USA.
Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, USA.
Soft Matter. 2019 Jan 21;15(3):381-392. doi: 10.1039/c8sm02142b. Epub 2018 Dec 11.
Cavity expansion can be used to measure the local nonlinear elastic properties in soft materials, regardless of the specific damage or instability mechanism that it may ultimately induce. To that end, we introduce a volume-controlled cavity expansion procedure and an accompanying method that builds on the Cavitation Rheology technique [J. A. Zimberlin et al., Soft Matter, 2007, 3, 763-767], but without relying on the maximum recorded pressure. This is achieved by determining an effective radius of the cavity that is based on the volume measurements, and is further supported by numerical simulations. Applying this method to PDMS samples, we show that it consistently collapses the experimental curves to the theoretical prediction of cavity expansion prior to the occurrence of fracture or cavitation, thus resulting in high precision measurement with less than 5% of scatter and good agreement with results obtained via conventional techniques. Moreover, since it does not require visual tracking of the cavity, this technique can be applied to measure the nonlinear elastic response in opaque samples.
腔扩张可用于测量软物质的局部非线性弹性特性，而无需考虑其最终可能导致的特定损伤或失稳机制。为此，我们引入了一种体积控制的腔扩张程序和一种伴随的方法，该方法基于空化流变技术[J. A. Zimberlin 等人，《软物质》，2007 年，第 3 卷，第 763-767 页]，但不依赖于记录的最大压力。这是通过确定基于体积测量的腔的有效半径来实现的，并且得到了数值模拟的支持。将该方法应用于 PDMS 样品，我们表明它在发生断裂或空化之前，一致地将实验曲线压缩到腔扩张的理论预测，从而实现了高精度测量，散度小于 5%，并且与通过传统技术获得的结果吻合良好。此外，由于它不需要对腔进行视觉跟踪，因此该技术可用于测量不透明样品的非线性弹性响应。
