Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 24 for “"shear banding"”.
-
Analysis of Adiabatic Shear Banding in a Thick-Walled Steel Tube by the Finite Element Method
The initiation and propagation of adiabatic shear bands is analyzed numerically for an impulsively loaded thick-walled steel tube. A circumferential V-notch located at the outer surface of the center of the tube provides a stress concentration. The material is modeled as strain hardening, …
-
Local Water Slamming of Nonlinear Elastic Sandwich Hulls, and Adiabatic Shear Banding in Simple Shearing Deformations of Thermoelastoviscoplastic Bodies
We have developed a third-order shear and normal deformable plate/shell theory (TSNDT) incorporating all geometric nonlinearities and used it to analyze, by the finite element method (FEM), transient finite deformations of a sandwich beam with two face sheets and the core made of St. …
-
Understanding self-assembly and flow heterogeneities in poloxamer wormlike micelles
… nonlinear flow behavior such as the formation of shear bands and other flow heterogeneities, which have garnered considerable scientific interest. While often formulated using small molecule ionic surfactants, WLMs can also form in solutions of amphiphilic block polymers. The most well-studied of …
-
Role of viscoelasticity and non-linear rheology in flows of complex fluids at high deformation rates
… the fluid rheology plays a dominant role: 1) shear banding in micellar fluids, 2) extension-dominated flows in microfluidic devices, and 3) flow-induced particle migration in microchannels. Firstly, worm-like micellar solutions are model non-Newtonian fluids having a single relaxation time …
-
Thermomechanical Modeling of Oxidation Effects in Porous Ultra-High Temperature Ceramics
… at room temperature. The 10% and 40% RVEs showed shear banding and subsequent shear failure of the inter-pore struts, while shear banding in 70% RVE weakened the struts, which lead to buckling failure. A snapshot oxidation model was then applied to the hexagonal RVEs in place of a transient, …
-
Dynamic Shear Bands in Metals under High Strain Rates
Adiabatic shear bands have been observed for a long time to occur under different conditions in many applications. Analysis of these localizations highly depends on the selection of the constitutive model. Hence, two constitutive models that take temperature and strain rate effect into account are …
-
Development of an efficient finite volume computational platform for the simulation of complex flows of complex fluids governed by the Rolie-Poly model
… flows but are not able to do so in some cases, shear-banding phenomena being one of them. Under certain flow conditions, some complex fluids have been shown to exhibit different shear bands in the flow field due to flow-induced material non-homogeneities. It is becoming increasingly clear that …
-
Complex fluid dynamical computations via the Finite Volume Method
… fluid dynamical processes associated with shear banding.
-
Microplasticity in metallic glasses
… to macroscopic strain localization and therefore shear banding. We use a coherent x-ray scattering technique (x-ray photon correlation spectroscopy or XPCS) to probe the lower stress range, whereas an in-situ acoustic emission (AE) technique is used to track structural activity close to yielding. …
-
Deformation Localization in Constrained Layers of Metallic Glasses: A Parametric Modeling Analysis
Localized plastic deformation known as shear banding is a prominent feature in metallic glasses. In this study we perform parametric three-dimensional finite ele- ment analyses, using primarily a thin layer of metallic glass on top of a cylindrical base, to study how physical constraint can affect …
-
Simulated Associating Polymer Networks
… the gel under the application of a constant shear is studied, with a focus on shear banding and the changes in topology under shear. Finally, the relation between the gel transition and percolation is discussed.</p>
-
Localization and instability in sheared granular materials: role of friction and vibration
Shear banding and stick-slip instabilities have been long observed in sheared granular materials. Yet, their microscopic underpinnings, interdependencies and variability under different loading conditions have not been fully explored. Here, we use a non-equilibrium thermodynamics model, the Shear …
-
The rheological complexity of waxy crude oils : yielding, thixotropy and shear heterogeneities
… The three phenomena studied are, first: shear heterogeneities, i.e. the manifestation of wall slip, shear banding or other shear-localization events under imposed deformations that are assumed to be homogenous. For these purposes, flow visualization techniques capable of "Rheo-PIV" …
-
Structure, Rheology and Optical Properties of Plasmonic Fluids
… Specifically, non-monotonic dependence of zero shear viscosity on nanoparticle concentration, rheopexy, shear thickening, shear banding and shear thinning are observed. The fluids exhibit enhanced viscoelasticity upon the addition of more nanoparticles. The mechanical, rheological and optical …
-
Mechanical and microstructural characterization of nuclear grade PCEA graphite
… the mechanical properties. Dynamic Young’s and shear moduli obtained from fundamental frequency resonance testing revealed minor elastic anisotropy and narrow data scatter, indicating high structural uniformity. Comparison of static and dynamic modulus values demonstrated that microcrack closure …
-
Spatially resolved measurements of kinematics and flow-induced birefringence in worm-like micellar solutions undergoing high rate deformations
… undergoing strong deformations. First, the shear banding response of the CPyCl:NaSal system and shear thinning response of the CTAB:NaSal system were observed in Poiseuille flow through a rectilinear microchannel. Then the corresponding behavior in an extension-dominated flow through a …
-
Crash Analysis of Degraded Concrete Containment Structures
… during tip-over event are concrete crushing and shear banding.
-
Nonlinear rheology of micelles and polymers
… and compared with experiment. In steady shear flow, the shear stress is shown to decrease with increasing shear rate, according to the constitutive equation. This behaviour, which is also shown by the Doi-Edwards equation, is unphysical. Both theories fail to take into account the fact …
-
Simulation of concentrated non-Brownian frictional and adhesive suspensions in linear and nonlinear flows
… or concentrated suspensions in simple shear flow. Then, we study the role of adhesive forces in frictional suspensions, by varying both the intensity of adhesion and the volume fraction: after presenting the difficulties of simulating adhesive suspensions at low volume fractions due to …
Page 1 of 2