ItemPhysically-motivated models of polymer networks with dynamic cross-links: comparative study and future outlookZehnder, Alan; Cui, Fan; Hui, Chung-Yuen; Vernerey, Franck (Submitted to Proceedings of the Royal Society A, 2021-10-10)Data set used in paper submitted October 2021 to Proceedings of the Royal Society. ItemCrack Propagation in a PVA Dual-Crosslink Hydrogel: Crack Tip Fields Measured using Digital Image CorrelationLiu, Mincong; Guo, Jingyi; Hui, Chung-Yuen; Zehnder, Alan (2019-06)Data contained in plots of the associated paper. Submitted to Mechanics of Materials in June 2019 ItemThe stress field near the tip of a plane stress crack in a gel consisting of chemical and physical cross-linksGuo, Jingyi; Hui, Chung-Yuen; Liu, Mincong; Zehnder, Alan (2018-12-17)This data set is part of a study of the time dependent asymptotic stress fields near the tip of a Mode I plane stress crack. The analysis is based on a three-dimensional continuum model which describes the viscoelastic behavior of a hydrogel gel with permanent and transient cross-links. The viscoelasticity results from the breaking and healing of the transient cross-links in the gel network. We show that the crack tip fields satisfy a local correspondence principle – that is, the spatial singularities of these fields are identical to a hyper-elastic cracked body with the same but undamaged networks. Asymptotic results compare very well with finite element (FE) simulations on a single edge crack specimen loaded under constant stretch rate. We also compare the theoretical results (crack opening profile) with experiments and the agreement is excellent. The dominant strain field in our theory also agrees well with Digital Image Correlation (DIC). Data included are: Sample Abaqus input file, Fortran code for user material (UMAT), and all data contained in the plots. The files are named according to the corresponding figure number in the paper, submitted to the Proceedings of the Royal Society, A, on December 18, 2018. ItemMode III Fracture in Rods Under Torsion: Experiments and SimulationsZehnder, Alan (2016-08)Under torsional loading, circumferentially notched rods of a brittle material will fracture either in a spiral shape or along a nominally flat, but faceted surface. These facets are the result of multiple microcracks emanating at 45 degrees from the notch and linking together as the crack propagates. Additional experimental results, visualizations and computational simulations are presented and analyzed here with the goal of providing further insight into the dynamic evolution of fracture under such loadings. ItemLecture Notes on Fracture MechanicsZehnder, Alan (2009-07-30)This book is written for students who want to understand, apply and contribute to the vast and growing field of fracture mechanics. The emphasis is on mechanics models for crack tip fields and energy flows. A brief discussion of computational fracture methods is given along with applied aspects such as fracture toughness testing and fracture criteria. As I intend to update the notes, I would be happy to take any suggestions or corrections and am open to collaboration to expand the coverage.