Experimental study on penny-shaped fluid-driven cracks in an elastic matrix

2015 ◽  
Vol 471 (2182) ◽  
pp. 20150255 ◽  
Author(s):  
Ching-Yao Lai ◽  
Zhong Zheng ◽  
Emilie Dressaire ◽  
Jason S. Wexler ◽  
Howard A. Stone
Keyword(s):  
Elastic Matrix ◽  
Laboratory Model ◽  
Fluid Viscosity ◽  
Gelatin Matrix ◽  
Crack Shape ◽  
Elastic Stresses ◽  
Surrounding Matrix ◽  
Injection Flow ◽  
The Matrix ◽  
Scaling Arguments

When a pressurized fluid is injected into an elastic matrix, the fluid generates a fracture that grows along a plane and forms a fluid-filled disc-like shape. We report a laboratory study of such a fluid-driven crack in a gelatin matrix, study the crack shape as a function of time and investigate the influence of different experimental parameters such as the injection flow rate, Young’s modulus of the matrix and fluid viscosity. We choose parameters so that effects of material toughness are small. We find that the crack radius R ( t ) increases with time t according to t α with α =0.48±0.04. The rescaled experimental data at long times for different parameters collapse based on scaling arguments, available in the literature, showing R ( t )∝ t 4/9 from a balance of viscous stresses from flow along the crack and elastic stresses in the surrounding matrix. Also, we measure the time evolution of the crack shape, which has not been studied before. The rescaled crack shapes collapse at longer times and show good agreement with the scaling arguments. The gelatin system provides a useful laboratory model for further studies of fluid-driven cracks, which has important applications such as hydraulic fracturing.

Effect of temperature on composite films made with activated carbon, graphite, or graphene oxide (GO) in a gelatin matrix

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 77-95
Author(s):  
Siqiao Yang ◽  
Haichao Li
Keyword(s):  
Contact Angle ◽  
Activated Carbon ◽  
Water Absorption ◽  
Composite Films ◽  
Effect Of Temperature ◽  
Gelatin Matrix ◽  
Vapour Permeability ◽  
Blending Method ◽  
The Matrix ◽  
Different Temperatures

Activated carbon, graphite, and GO/gelatin composite films were prepared by the blending method. The properties of composites were characterized by tensile strength (TS), elongation at break (EB), water vapour permeability (WVP), water-absorption ability, contact angle, scanning electron microscopy (SEM), and moisture at different temperatures. The properties of GO/gelatin composite films were better when each of three kinds of carbon materials were used as reinforcement phases and added into the matrix gelatin. The results showed that EB and TS of GO/gelatin composite films were both excellent. The moisture of GO/gelatin composite films was greater than the others. SEM micrographs showed that GO had better compatibility and dispersibility with gelatin than activated carbon and graphite. The water absorption of GO/gelatin composite films were low, at 15 °C and 25 °C, and the WVP was low at 35 °C. The WVP of GO/gelatin composite films was lower than the others at different temperatures. The contact angle of GO/gelatin composite films was larger than the others.

ANALYSIS OF PROTEOGLYCAN GENE EXPRESSION IN CONNECTIVE TISSUES BY SEMI-QUANTITATIVE RT-PCR

2001 ◽  
Vol 05 (02) ◽  
pp. 79-88
Author(s):  
K. Dobra ◽  
A. Hjerpe
Keyword(s):  
Rt Pcr ◽  
Connective Tissues ◽  
Surrounding Matrix ◽  
Cell Proliferation And Differentiation ◽  
Extracellular Matrix Components ◽  
Proliferation And Differentiation ◽  
The Matrix ◽  
Quantitative Changes ◽  
Regulatory Functions ◽  
Multiple Samples

Proteoglycans (PGs) are cell-membrane and extracellular matrix components with a wide variety of different functions. In the matrix, they are mainly of structural importance, although some of them have been ascribed specific regulatory functions, such as in the assembly of collagen fibers. PGs on the cell surface act as essential modulators of specific ligand-binding reactions, involving interactions between adjacent cells and between cells and surrounding matrix. Through these interactions they participate in different processes, including cell proliferation and differentiation. Qualitative and quantitative changes in PG expression can therefore be associated with various physiological and pathological conditions. We have optimized the conditions for semi-quantitative evaluation of proteoglycan expression by RT-PCR reaction, using glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as reference gene. The relative fluorescence of analyte to reference amplimers can — within certain limits — be used to estimate the amount of target RNA and allows direct comparison of multiple samples. The profile of PG expression obtained in this way can be used to extend our current understanding of the possible functions that can be associated with these complex molecules.

An elastic harmonic inclusion near a rigid harmonic inclusion loaded by a couple

2019 ◽  
Vol 84 (3) ◽  
pp. 555-566
Author(s):  
Xu Wang ◽  
Liang Chen ◽  
Peter Schiavone
Keyword(s):  
Rigid Inclusion ◽  
Elastic Inclusion ◽  
Complex Loading ◽  
Solution Procedure ◽  
External Loading ◽  
Surrounding Matrix ◽  
The Matrix ◽  
Mapping Techniques ◽  
Loading Parameter ◽  
Harmonic Inclusion

AbstractWe use conformal mapping techniques to solve the inverse problem concerned with an elastic non-elliptical harmonic inclusion in the vicinity of a rigid non-elliptical harmonic inclusion loaded by a couple when the surrounding matrix is subjected to remote uniform stresses. Both a size-independent complex loading parameter and a size-dependent real loading parameter are introduced as part of the solution procedure. The stress field inside the elastic inclusion is uniform and hydrostatic; the interfacial normal and tangential stresses as well as the hoop stress on the matrix side are uniform along each one of the two inclusion–matrix interfaces. The tangential stress along the interface of the elastic inclusion (free of external loading) vanishes, whereas that along the interface of the rigid inclusion (loaded by the couple) does not. A novel method is proposed to determine the area of the rigid inclusion.

Observation and Mearsurement of Concentration Moments in Rapid Coarsening, Self-Stressed, Au-Ni Thin Plates

2000 ◽  
Vol 6 (S2) ◽  
pp. 360-361
Author(s):  
B. Hyde ◽  
W.T. Reynolds
Keyword(s):  
Elastic Stress ◽  
Lattice Misfit ◽  
Host Lattice ◽  
Thin Plates ◽  
Two Phase ◽  
Elastic Stresses ◽  
Buckling Stress ◽  
The Matrix ◽  
Coarsening Kinetics ◽  
Rapid Coarsening

The focus of our study is to demonstrate experimentally how elastic stress effects diffusion behavior and coarsening kinetics in a two-phase binary alloy. This work, based on the theory of Cahn and Kobayashi, focuses on elastic stresses in a thin plate. For the case of phase separation with lattice misfit between solute-rich and solute-poor phases, the diffusion of solute distorts the host lattice and causes elastic stress in the matrix. If the plate is sufficiently thin, the stress can cause the plate to buckle. The buckling stress biases the direction of diffusion, which increases the bending stress even further. Thus, the diffusion and the buckling stress are coupled; each affects the other. The interplay between the two is easiest to observe in a solution in which the solute and solvent have high misfit.

scholarly journals A Facile Method to Fabricate Anisotropic Extracellular Matrix with 3D Printing Topological Microfibers

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3944 ◽  
Author(s):  
Zhen Gu ◽  
Zili Gao ◽  
Wenli Liu ◽  
Yongqiang Wen ◽  
Qi Gu
Keyword(s):  
Mechanical Properties ◽  
Extracellular Matrix ◽  
Mechanical Characteristics ◽  
Fiber Direction ◽  
Gelatin Matrix ◽  
Simple Method ◽  
Elongation At Break ◽  
Anisotropic Mechanical Properties ◽  
The Matrix ◽  
3D Printed

Natural tissues and organs have different requirements regarding the mechanical characteristics of response. It is still a challenge to achieve biomaterials with anisotropic mechanical properties using an extracellular matrix with biological activity. We have improved the ductility and modulus of the gelatin matrix using 3D printed gelatin microfibers with different concentrations and topologies and, at the same, time achieved anisotropic mechanical properties. We successfully printed flat microfibers using partially cross-linked gelatin. We modified the 10% (w/v) gelatin matrix with microfibers consisting of a gelatin concentration of 14% (w/v), increasing the modulus to about three times and the elongation at break by 39% in parallel with the fiber direction. At the same time, it is found that the microfiber topology can effectively change the matrix ductility, and changing the modulus of the gelatin used in the microfiber can effectively change the matrix modulus. These findings provide a simple method for obtaining active biological materials that are closer to a physiological environment.

scholarly journals Translation of a Coated Rigid Spherical Inclusion in an Elastic Matrix: Exact Solution, and Implications for Mechanobiology

2019 ◽  
Vol 86 (5) ◽  
Author(s):  
Xin Chen ◽  
Moxiao Li ◽  
Shaobao Liu ◽  
Fusheng Liu ◽  
Guy M. Genin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Exact Solution ◽  
Analytical Solution ◽  
Spherical Inclusion ◽  
Matrix Material ◽  
Elastic Matrix ◽  
Protein Ligands ◽  
First Case ◽  
The Matrix ◽  
Matrix Modulus

The displacement of relatively rigid beads within a relatively compliant, elastic matrix can be used to measure the mechanical properties of the matrix. For example, in mechanobiological studies, magnetic or reflective beads can be displaced with a known external force to estimate the matrix modulus. Although such beads are generally rigid compared to the matrix, the material surrounding the beads typically differs from the matrix in one or two ways. The first case, as is common in mechanobiological experimentation, is the situation in which the bead must be coated with materials such as protein ligands that enable adhesion to the matrix. These layers typically differ in stiffness relative to the matrix material. The second case, common for uncoated beads, is the situation in which the beads disrupt the structure of the hydrogel or polymer, leading to a region of enhanced or reduced stiffness in the neighborhood of the bead. To address both cases, we developed the first analytical solution of the problem of translation of a coated, rigid spherical inclusion displaced within an isotropic elastic matrix by a remotely applied force. The solution is applicable to cases of arbitrary coating stiffness and size of the coating. We conclude by discussing applications of the solution to mechanobiology.

Diffusion of 65Zn in AZ91 and QE22 Alloys with Saffil Reinforcement-Influence of Interfaces Matrix/Saffil

2009 ◽  
Vol 289-292 ◽  
pp. 145-152
Author(s):  
Ivo Stloukal ◽  
Jiří Čermák
Keyword(s):  
Temperature Interval ◽  
Diffusion Coefficients ◽  
Volume Diffusion ◽  
Effective Diffusion ◽  
Measured Temperature ◽  
Elastic Stresses ◽  
Effective Diffusion Coefficients ◽  
Sectioning Method ◽  
The Matrix ◽  
Zinc Diffusion

Diffusion of 65Zn in two commercial Mg-based alloys AZ91 and QE22 with short Saffil fibers was studied. Experiments were carried out in the temperature interval 648 – 728 K by serial sectioning method. The effective diffusion coefficients Deff were compared with 65Zn diffusion coefficients Dv obtained with the same alloys without Saffil fibers. The evaluation of the influence of the interface between the matrix and the fibers upon Deff was done and the zinc diffusion coefficient Di in the interface boundary matrix/Saffil was estimated. Unlike the Arrhenius-like behavior of volume diffusion in both alloys, it was observed that the temperature dependence of both Deff and Di was significantly concave in the measured temperature interval. This behavior was attributed to relaxation of thermo-elastic stresses in the composite induced by a large difference between coefficients of thermal expansion (CTE) of Saffil fibers and metal matrix. The maximum values of Deff and Di, respectively, lie close to 693 K, where CTE has a minimum.

A Study on the Thermoelastic Analysis in Shear Deformable Discontinuous Composites

2004 ◽  
Vol 261-263 ◽  
pp. 645-650
Author(s):  
Hong Gun Kim
Keyword(s):  
Thermal Stresses ◽  
Volume Fraction ◽  
Coefficient Of Thermal Expansion ◽  
Fiber Composite ◽  
Element Model ◽  
Short Fiber ◽  
Elastic Stresses ◽  
Fiber Aspect Ratio ◽  
The Matrix ◽  
Lag Model

A stress analysis has been performed to evaluate the thermally induced elastic stresses which can develop in a short fiber composite due to coefficient of thermal expansion (CTE) mismatch. An axisymmetric finite element model with the constraint between cells has implemented to find the magnitude of thermoelastic stresses in the fiber and the matrix as a function of volume fraction, CTE ratio, modulus ratio, and fiber aspect ratio. It was found that the matrix end regions fall under significant thermal stresses that have the same sign as that of the fibers themselves. Furthermore, it was found that the stresses vary along the fiber and fiber end gap in the same manner as that obtained in a shear-lag model during non-thermal mechanical loading.

Residual strain energy in composites containing particles

1996 ◽  
Vol 11 (2) ◽  
pp. 483-494 ◽  
Author(s):  
Toshiaki Mizutani
Keyword(s):  
Strain Energy ◽  
Crystal Lattices ◽  
Composite Systems ◽  
Surrounding Matrix ◽  
Dispersed Particles ◽  
First Approximation ◽  
Bulk Stress ◽  
The Matrix ◽  
Unit Cells ◽  
Physical Validity

Selsing's formula for radial tension at the particle-matrix interface is extended into a general formula which includes the effects of the amount of dispersed particles. A relationship is derived between individual volumes of strained unit cells in the crystal lattices of the particles and of the surrounding matrix. These relationships are used to predict the effect of the particles (2H−TiB2, 2H−ZrB2, and t−WB) on their unit cells and on the unit cell of the surrounding 6H–SiC matrix. The precision of these predictions was 7.1% or better. Hence, in principle, it is possible to investigate the distributions of residual bulk stress/strain. Estimates of characterizing values of the three composite systems are attempted on the rough basis of the elastic constants of the SiC matrix, confirming the physical validity of this approach as a first approximation. Further, the residual bulk strain energies of the particles and the matrix are discussed in connection with the elastic term involved in the fracture energy of such composites.

A two-dimensional circular inclusion problem

1969 ◽  
Vol 65 (3) ◽  
pp. 823-830 ◽  
Author(s):  
R. D. List
Keyword(s):  
Edge Dislocation ◽  
Circular Inclusion ◽  
Elastic Matrix ◽  
Inclusion Problem ◽  
Two Dimensional ◽  
Concentrated Force ◽  
Elastic Fields ◽  
The Matrix ◽  
Elastic Circular Inclusion

AbstractThe elastic fields in an elastic circular inclusion and its surrounding infinite dissimilar elastic matrix, are determined when either the matrix or inclusion is subject to a concentrated force or edge dislocation.

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