This book provides a review of the current understanding of the behavior of non-spherical particle suspensions providing experimental results, rheological models and numerical modeling. In recent years, new models have been developed for suspension rheology and as a result applications for nanocomposites have increased. The authors tackle issues within experimental, model and numerical simulations of the behavior of particle suspensions. Applications of non-spherical particle suspension rheology are widespread and can be found in organic matrix composites, nanocomposites, biocomposites, fiber-filled fresh concrete flow, blood and biologic fluids. Understand how to model and predict the final microstructure and properties of particle suspensions Explores nano, micro, meso and macro scales Rheology, thermomechanical and electromagnetic physics are discussed

Research program on the rheological properties of flowing suspensions. The primary purpose of the research supported by this grant was to study the flow characteristics of concentrated suspensions of non-colloidal solid particles and thereby construct a comprehensive and robust theoretical framework for modeling such systems quantitatively. At first glance, this seemed like a modest goal, not difficult to achieve, given that such suspensions were viewed simply as Newtonian fluids with an effective viscosity equal to the product of the viscosity of the suspending fluid times a function of the particle volume fraction. But thanks to the research findings of the Principal Investigator and of his Associates, made possible by the steady and continuous support which the PI received from the DOE Office of Basic Energy Sciences, the subject is now seen to be more complicated and therefore much more interesting in that concentrated suspensions have been shown to exhibit fascinating and unique rheological properties of their own that have no counterpart in flowing Newtonian or even non-Newtonian (polymeric) fluids. In fact, it is generally acknowledged that, as the result of these investigations for which the PI received the 2001 National Medal of Science, our understanding of how suspensions behave under flow is far more detailed and comprehensive than was the case even as recently as a decade ago. Thus, given that the flow of suspensions plays a crucial role in many diverse physical processes, our work has had a major and lasting impact in a subject having both fundamental as well as practical importance.

Presented in an accessible and introductory manner, this is the first book devoted to the comprehensive study of colloidal suspensions.

The relationship between colloidal suspension microstructure and rheology is investigated to provide a solid understanding of the nonlinear rheology of concentrated suspensions, with a focus on shear thickening. These suspensions are also studied as a treatment to woven fabric in body-armor applications, where the insight from microstructural measurements is used to attempt to improve the application. The colloid and suspension properties are characterized via SEM, DLS, SANS, USANS, and rheometry. The rheology is mapped onto an effective hard-sphere model with the addition of a yield stress. An additional excluded volume shell, as measured by SANS and USANS structural measurements, accounts for interparticle interactions due to surface forces arising from the stabilizing layer on the particles. The microstructure of these near hard-sphere concentrated, shear-thickening colloidal dispersions are measured via SANS and USANS as a function of volume fraction, shear rate, and particle size. Special Rheo-SANS, flow-SANS, and flow-USANS instruments are developed and validated to measure microstructure in flowing systems. Structures measured via USANS show a cluster peak that arises from hydrocluster formation in concentrated, shear thickening suspensions. Structure measurements in SANS via 1-d averaged analysis and analysis of the 2-d structure corresponds to that expected from Stokesian Dynamics simulations. Micromechanics theory via a Stress-SANS law is used to calculate rheology from the microstructure for comparison. As the rheology calculated from the SANS data qualitatively agrees with that of the suspension and the structures seen correspond to those expected from simulations, strong confirmation of the hydrocluster mechanism for shear thickening is observed. This improved knowledge of the hydrocluster structure is used to develop an elastohydrodynamic theory for the limiting viscosity at high shear stresses due to particle deformations in the hydrocluster. Measurements of particle modulus give consistent application of this elastohydrodynamic model to suspensions studied in this thesis. In addition, the model is applied to widely varying suspensions, including those of hard mineral particles, polymer particles, microgels, and emulsions and consistent results are seen. The results of these fundamental studies of how particle size, concentration, and hardness affect suspension microstructure and rheology are used to engineer shear thickening fluid treated textiles, suitable for various types of protective devices.

Essential text on the practical application and theory of colloidal suspension rheology, written by an international coalition of experts.