Particle Deformation

Author(s):  
Joseph L. Keddie ◽  
Alexander F. Routh
Keyword(s):  
Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 55
Author(s):  
Cheolheon Park ◽  
Junghyun Bae ◽  
Yeongjae Choi ◽  
Wook Park

We demonstrate that it is possible to produce microparticles with high deformability while maintaining a high effective volume. For significant particle deformation, a particle must have a void region. The void fraction of the particle allows its deformation under shear stress. Owing to the importance of the void fraction in particle deformation, we defined an effective volume index (V*) that indicates the ratio of the particle’s total volume to the volumes of the void and material structures. We chose polyethylene glycol diacrylate (Mn ~ 700) for the fabrication of the microparticles and focused on the design of the particles rather than the intrinsic softness of the material (E). We fabricated microparticles with four distinct shapes: discotic, ring, horseshoe, and spiral, with various effective volume indexes. The microparticles were subjected to shear stress as they were pushed through a tapered microfluidic channel to measure their deformability. The deformation ratio R was introduced as R = 1−Wdeformed/Doriginal to compare the deformability of the microparticles. We measured the deformation ratio by increasing the applied pressure. The spiral-shaped microparticles showed a higher deformation ratio (0.901) than those of the other microparticles at the same effective volume index.


Soft Matter ◽  
2018 ◽  
Vol 14 (2) ◽  
pp. 216-227 ◽  
Author(s):  
Margaret Y. Hwang ◽  
Seo Gyun Kim ◽  
Heon Sang Lee ◽  
Susan J. Muller

Experimental deformation of hydrogel soft particles in a confined channel is quantified and can be used to obtain shear modulus.


2019 ◽  
Vol 813 ◽  
pp. 110-115
Author(s):  
Olga Matts ◽  
Hussein Hammoud ◽  
Alexey Sova ◽  
Zineb Bensaid ◽  
Guillaume Kermouche ◽  
...  

In this work an influence of cold spray nozzle displacement parameters on the properties of copper-silicon carbide cold spray deposits is considered. In particular the influence of nozzle traverse speed and distance between deposited tracks on the coating porosity and behavior during compressive tests was analyzed. It was shown that cold spraying at low nozzle traverse speed leads to formation of thick tracks with quasi-triangular cross-section. As a consequence, the particle impact angle on the sides of spraying track increases that. Thus, the particle deformation at impact on the track periphery becomes insufficient and local porosity value rises. Increase of nozzle traverse speed allows increasing coating density and mechanical properties due to amelioration of particle deformation conditions. Compressive tests revealed significant anisotropy of mechanical properties of copper-silicon carbide cold spray deposits. In particular, compressive strength measured in vertical direction (perpendicular to the substrate) was significantly higher than one measured in horizontal plane (parallel to substrate). This anisotropy could be explained by the orientation of particle deformation pattern during impact.


Geosciences ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 246 ◽  
Author(s):  
James Buckman ◽  
Sean Higgins

Sandstones and many carbonates (e.g., oolitic limestone and other grainstones), comprise solid particulates (grains) and pores, which have a given pore network architecture relationship, and associated porosity—permeability values. Over time, through the process of diagenesis, the pore network architecture may be extensively altered. Changes can include compaction, particle deformation, cementation, dissolution and fracturing, with the pathway followed after deposition depending on factors such as the energy level, rate of burial, degree of biological activity, local heat flow, sediment composition, Eh, pH and the presence or absence of organic materials. Any method that provides a means of modelling changes is therefore highly desirable, in particular, allowing a prediction of changes in porosity and permeability with time. The current work illustrates a simple method that uses freely available open source image analysis software to model the development of cement phases within an oolitic limestone in three-dimensions. As well as cementation, it demonstrates the modelling of fracture development and dissolution processes, and records how porosity and permeability change during such processes.


1967 ◽  
Vol 28 (4) ◽  
pp. 657-673 ◽  
Author(s):  
J. D. Goddard ◽  
Chester Miller

An analysis is presented of the deformation of a solid-like, viscoelastic sphere suspended in the infinite Stokesian flow field of a Newtonian fluid undergoing an arbitrary time-dependent homogeneous deformation far from the particle. The results of the analysis are then used to deduce the macroscopic rheological behaviour of a dilute monodisperse suspension of slightly deformable spheres.Even though inertial effects and second-order terms in the particle deformation are neglected, it is found that non-linear rheological effects can arise, because of the interaction between the deformed particle and the flow. As a consequence, the rheological relation obtained here differs from those presented earlier by Fröhlich & Sack (1946) and by Oldroyd (1955) through the appearance of certain terms which are non-linear in the deformation rate.When the suspended particles are purely elastic in their behaviour the rheological equation presented here reduces for certain flows to a special case of Oldroyd's (1958) phenomenological model, with material constants which can be directly related to suspension properties.


Sign in / Sign up

Export Citation Format

Share Document