Design tools for linear viscoelastic fluids

摘要

Engineering design often makes use of conventional materials such as hard, elastic solids and simple, Newtonian fluids. Rheologically-complex materials (non-Newtonian fluids and soft solids) demonstrate useful and novel properties in both engineered and biological systems. Incorporating these materials in rational engineering design stands to vastly enhance the design space and allow for improvements in technology in areas including vibration isolation, 3D printing, soft robotics, energy storage, adhesion, and coatings. To date, most work in the space of materials and design has focused on characterization of novel materials, material selection, material processing optimization, or material processing optimization. Thus making use of materials with novel functionality often occurs through trial and error or kismet of matching a new material to a novel use. To truly utilize rheologically complex materials, we must use a rational design process. In this thesis, we build up the necessary foundations for utilizing a sub-class of rheologically-complex materials – materials that exhibit linear viscoelastic behavior – for design. \n\nThis work develops the framework necessary to incorporate linear viscoelastic materials into the designer's toolbox. First, we think deeply about ways to describe linear viscoelastic behavior for development of intuition for these materials and for rational design. We make extensive use of the continuous relaxation spectra description of the material response $H(\\tau)$ an important design-appropriate material description to define low-dimensional material descriptions. We use these material descriptions to build cross-property Ashby-style diagrams that incorporate information about the complex-function valued material response in a compact and accessible format. Next we develop the mathematical framework for rational design and computational optimization with linear viscoelastic materials. This framework is applied to multiple vibration isolation design scenarios.\n\nIn this work, we have built the framework to vastly expand the material design space and allow for improvements in technology in areas including vibration isolation, 3D printing, soft robotics, energy storage, and adhesion.