Y-Shaped Cutting of Soft Solids: History and Best Practices

Background: Though proposed by Lake and Yeoh in 1978 for vulcanized rubber characterization and possessing unique advantages with respect to traditional fracture characterization approaches, the Y-shaped cutting technique has been applied to a limited number of materials. Objective: This limited implementation may be due to researchers’ unfamiliarity with the effects of Y-shaped cutting conditions and technique limitations, as well as a lack of standards. This review and best practices guide aims to provide a detailed road-map of the capabilities of Y-shaped cutting, with guidance for designing, executing, and interpreting its results. Method: By performing Y-shaped cutting at a constant blade propagation rate, fracture initiation effects encountered in many ‘tearing’ tests are bypassed. Meanwhile, unlike other contact-driven fracture conditions (needle insertion or cutting), the ‘leg’ separation renders the cutting nearly ‘frictionless’ under a variety of conditions. Results: Y-shaped cutting possesses two unique attributes. Under certain conditions (Zhang and Hutchens in Soft Matter 17(28):6728–6741, 2021), it can yield a fracture energy independent of sample and cutting implement geometry. In contrast to soft solid crack blunting, cutting reduces both the finite stretch and failure process zones to within a field of view readily imaged on a microscope, useful for microstructural studeis. To facilitate access to the above advantages, we summarize experimental variables and their role the fracture response and/or successful cutting and establish a pseudo-standard using silicone. Conclusion: This overview and recommendations empowers researchers to implement this highly-tunable cutting method in order to provide insights into other classes of materials in the future.