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Basic Rheological Concepts: Stress, Strain, and Flow
Published in Kevin P. Menard, Noah R. Menard, Dynamic Mechanical Analysis, 2020
Kevin P. Menard, Noah R. Menard
The term rheology seems to generate a slight sense of terror in the average worker in materials. Rheology is defined as the study of the deformation and flow of materials. The term was coined by Bingham to describe the work being done in modeling how materials behave under heat and force. Bingham thought that chemists would be frightened away by the term continuum mechanics,1 which was the name of the branch of physics concerned with these properties. This renaming was one of science’s less successful marketing ploys, as most chemists think rheology is something only done by engineers with degrees in non-Newtonian fluid mechanics and most likely in dark rooms.
Rheological behavior of tsunami run-up water containing alluvial deposit at coastline of Kedah, Malaysia
Published in Noor Amila Wan Abdullah Zawawi, Engineering Challenges for Sustainable Future, 2016
A.K. Philip, H.M. Teh, S.H. Shafiai, A. Jaafar, A.H.M. Rashidi
Rheology is the study of fluid deformation to classify the behavior into two general categories i.e. Newtonian and non-Newtonian. As defined by Lorenzini and Mazza (2004), Newtonian fluid refers to those fluid having a direct relationship between shear stress and shear rate e.g. water and oil. Non-Newtonian, on the other hand, is fluid that exhibit apparent change in viscosity (strain) with increasing shear rate, hence also affecting the applied shear stress. Two behaviors are observed in this class which are shear-thinning and shear-thickening. Shear-thinning or pseudoplastic fluid is characterize by the decrease in viscosity with increasing shear rate e.g. blood and paint. Contrary, shear-thickening or dilatant fluid shows an increase in viscosity with increasing shear rate e.g. starch mixture and quicksand. Additionally, there is also a non-Newtonian Bingham fluid, in which the fluid will flow as Newtonian, pseudoplastic or dilatant type after the yield stress was achieved (Lorenzini & Mazza, 2004). Other types of non-Newtonian fluid are thixotropy and rheopexy, a time-dependent change in viscosity.
Solid—Fluid Systems
Published in Enrique Ortega-Rivas, Unit Operations of Particulate Solids, 2016
According to rheology, which embraces the study of flow behavior in very general way, there are two main types of flow: viscous and elastic. The first occurs in fluids, whereas the second is common to solids. An intermediate behavior of flow in between is also found. Thus, perhaps the most useful classification that, in terms of flow behavior, can be made is by means of a spectrum extending from elastic solids on one extreme to viscous flow on the other. Because the laws governing solids flow differ totally from those describing fluids flow, viscous and viscoelastic flow are normally studied together. Table 10.1 presents a summary of the main types of fluids.
Investigating the free vibration of viscoelastic FGM Timoshenko nanobeams resting on viscoelastic foundations with the shear correction factor using finite element method
Published in Mechanics Based Design of Structures and Machines, 2022
Ghali Drici, Ismail Mechab, Hichem Abbad, Noureddine Elmeiche, Belaid Mechab
Viscoelasticity is generally defined as the property possessed by materials which exhibit both viscous and elastic characteristics when undergoing deformation. It should be noted that viscous materials resist shear flow and exhibit deformation that increases linearly with time when stress is applied to them (creep and relaxation). In addition, elastic materials deform when subjected to stresses, but quickly return to their original state once those stresses are removed. Moreover, in rheology a viscoelastic material presents an intermediate linear behavior between that of an ideal elastic solid that can be symbolized by a spring having a particular stiffness and that of a Newtonian viscous liquid that can be symbolized by a viscous damping coefficient. It is worth recalling that the viscosity of a material reflects its ability to dissipate energy. Different models can be used to describe the linear viscoelasticity of a material. One may mention Maxwell’s model which is well suited to viscoelastic liquids. The Kelvin–Voigt model is an elementary model that applies to viscoelastic solids. In addition, the models of Zener and Burgers, which fit the two previous cases equally well, are also worth mentioning (Maxwell 1867; Chen and Chen 2014; Chaillat and Bui 2007; Zou et al. 2021) .
Effect of excess viscosifier and fluid loss control additive on the rheological characteristics of water-based drilling fluid
Published in Petroleum Science and Technology, 2023
Mike Uche Ajieh, Nosakhare Andrew Amenaghawon, Kesiena Owebor, Oghenero Henry Orugba, Esua Bassey Bassey
To efficiently apply drilling fluids for drilling operations, certain fluid characteristics are desired, such as the fluid density, rheological and filtration properties. Rheology is the study of fluid flow and deformation. It specifically relates shear stress to shear rate and the effects on the plastic viscosity, yield point and gel strength. These properties are very important for drilling fluids and largely account for the reason why fluids are suitable for drilling formations that have high porosity while attempting to maintain the rheological properties and not causing damage to crossed formations (Hamed and Belhadri 2009). Other properties include the ability to exhibit fluid loss prevention, stability of fluid under different temperature and pressure, and prevention of fluid contamination during operations, i.e., saltwater, calcium sulfate, cement and potassium. Nonetheless, it is of considerable importance for drilling fluid to exhibit high penetration properties, which enables fluid to wet the drill string and to keep clean the cutting surfaces of the drill bit. Essentially, a high degree of lubrication is key to minimizing friction between the drill string and the wall of the borehole, an extremely valuable outcome being the minimization of differential sticking (Pakdaman et al. 2019). The hydrostatic pressure of the drilling fluid column is sufficiently higher than the formation pressure so that the drill string is forced against the wall of the borehole and stuck. In addition, it is important for drilling fluid to have the ability to prevent shale/clay swelling of the formation, which is key to reducing drill string sticking, which results from preventing clays from absorbing water (Rafieefar et al. 2021a).
Time gap effect on bond strength of 3D-printed concrete
Published in Virtual and Physical Prototyping, 2019
Yi Wei Daniel Tay, Guan Heng Andrew Ting, Ye Qian, Biranchi Panda, Lewei He, Ming Jen Tan
Rheology is the science behind the material deformation and flow, which emphasis on the relationship between the stress, strain and time (Banfill 2006). The rheology of mortar, containing a range of particle size, is more complicated than one of its constituent material which is cement paste (Banfill 2003b). Banfill (2003a) mentions that the flow properties of suspensions are governed by the interface of the solid-water and the dominant contribution is the cement–water interface. Presence of aggregates will only dilute this flow behaviour. Therefore, in this study, the rheological testing only focusses on the paste instead of the mortar.