Microhardness and Young's modulus in cortical bone exhibiting a wide range of mineral volume fractions, and in a bone analogue

1990 ◽  
Vol 1 (1) ◽  
pp. 38-43 ◽  
Author(s):  
G. P. Evans ◽  
J. C. Behiri ◽  
J. D. Currey ◽  
W. Bonfield
Keyword(s):  
Cortical Bone ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Volume Fractions ◽  
Wide Range

scholarly journals Hardness, Young’s Modulus and Elastic Recovery in Magnetron Sputtered Amorphous AlMgB14 Films

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 823
Author(s):  
Alexander M. Grishin
Keyword(s):  
Young’S Modulus ◽  
Indentation Size Effect ◽  
Young's Modulus ◽  
Elastic Recovery ◽  
Rf Power ◽  
Magnesium Boride ◽  
Wide Range ◽  
Aluminum Magnesium Boride ◽  
Optical And Mechanical Properties ◽  
Diamond Probe

We report optical and mechanical properties of hard aluminum magnesium boride films magnetron sputtered from a stoichiometric AlMgB14 ceramic target onto Corning® 1737 Glass and Si (100) wafers. High target sputtering rf-power and sufficiently short target-to-substrate distance appeared to be critical processing conditions. Amorphous AlMgB14 films demonstrate very strong indentation size effect (ISE): exceptionally high nanohardness H = 88 GPa and elastic Young’s modulus E* = 517 GPa at 26 nm of the diamond probe penetration depth and almost constant values, respectively, of about 35 GPa and 275 GPa starting at depths of about 2–3% of films’ thickness. For comparative analysis of elastic strain to failure index  H/E*, resistance to plastic deformation ratio H3/E*2 and elastic recovery ratio We were obtained in nanoindentation tests performed in a wide range of loading forces from 0.5 to 40 mN. High authentic numerical values of H = 50 GPa and E* = 340 GPa correlate with as low as only 10% of total energy dissipating through the plastic deformations.

scholarly journals Optimized CNT-PDMS Flexible Composite for Attachable Health-Care Device

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4523 ◽  
Author(s):  
Jian Du ◽  
Li Wang ◽  
Yanbin Shi ◽  
Feng Zhang ◽  
Shiheng Hu ◽  
...  
Keyword(s):  
Composite Material ◽  
Percolation Threshold ◽  
Young’S Modulus ◽  
Cross Section ◽  
Young's Modulus ◽  
Large Strain ◽  
Weight Ratio ◽  
Linear Range ◽  
Wide Range ◽  
The Cross

The CNT-PDMS composite has been widely adopted in flexible devices due to its high elasticity, piezoresistivity, and biocompatibility. In a wide range of applications, CNT-PDMS composite sensors were used for resistive strain measurement. Accordingly, the percolation threshold 2%~4% of the CNT weight ratio in the CNT-PDMS composite was commonly selected, which is expected to achieve the optimized piezoresistive sensitivity. However, the linear range around the percolation threshold weight ratio (2%~4%) limits its application in a stable output of large strain (>20%). Therefore, comprehensive understanding of the electromechanical, mechanical, and electrical properties for the CNT-PDMS composite with different CNT weight ratios was expected. In this paper, a systematic study was conducted on the piezoresistivity, Young’s modulus, conductivity, impedance, and the cross-section morphology of different CNT weight ratios (1 to 10 wt%) of the CNT-PDMS composite material. It was experimentally observed that the piezo-resistive sensitivity of CNT-PDMS negatively correlated with the increase in the CNT weight ratio. However, the electrical conductivity, Young’s modulus, tensile strength, and the linear range of piezoresistive response of the CNT-PDMS composite positively correlated with the increase in CNT weight ratio. Furthermore, the mechanism of these phenomena was analyzed through the cross-section morphology of the CNT-PDMS composite material by using SEM imaging. From this analysis, a guideline was proposed for large strain (40%) measurement applications (e.g., motion monitoring of the human body of the finger, arm, foot, etc.), the CNT weight ratio 8 wt% was suggested to achieve the best piezoresistive sensitivity in the linear range.

Graphene oxide and zinc oxide decorated chitosan nanocomposite biofilms for packaging applications

2020 ◽  
Vol 40 (2) ◽  
pp. 152-157 ◽  
Author(s):  
Pınar Terzioglu ◽  
Yasin Altin ◽  
Ayse Kalemtas ◽  
Ayse Celik Bedeloglu
Keyword(s):  
Tensile Strength ◽  
Zinc Oxide ◽  
Graphene Oxide ◽  
Composite Film ◽  
Young’S Modulus ◽  
Mechanical Performance ◽  
Young's Modulus ◽  
Chitosan Film ◽  
Oxide Composite ◽  
Wide Range

AbstractRecently, due to sustainable development and environmental protection policies, there is increasing interest in the development of new biodegradable polymer-based multifunctional composites. Chitosan is one of the most remarkable and preferred biopolymers, which is environmentally friendly as well as renewable, biocompatible, and inexpensive. Though it has a wide range of potential applications, the major limitation of chitosan – the problem of poor mechanical performance – needs to be solved. In this work, graphene oxide was first produced and then used to manufacture a chitosan/graphene oxide/zinc oxide composite film through a casting method. The properties of the chitosan film and the chitosan/graphene oxide/zinc oxide composite film were investigated using Fourier transform infrared spectroscopy, mechanical, thermal gravimetric, and ultraviolet (UV)-visible spectroscopy analyses. The results showed that the incorporation of graphene oxide and zinc oxide into the chitosan matrix resulted in enhanced mechanical properties and thermal stability of chitosan biocomposite films. The graphene oxide- and zinc oxide-reinforced chitosan film showed 2527 MPa and 55.72 MPa of Young’s modulus and tensile strength, respectively, while neat chitosan showed only 1549 MPa and 37.91 MPa of Young’s modulus and tensile strength, respectively. Conversely, the addition of graphene oxide decreased the transmittance, notably in the UV region.

A Model for the Conductivity and Compliance of Unpropped and Natural Fractures

SPE Journal ◽  
2017 ◽  
Vol 22 (06) ◽  
pp. 1893-1914 ◽  
Author(s):  
Weiwei Wu ◽  
Mukul M. Sharma
Keyword(s):  
Plastic Deformation ◽  
Yield Stress ◽  
Young’S Modulus ◽  
Correlation Length ◽  
Young's Modulus ◽  
Heterogeneous Surfaces ◽  
Natural Fractures ◽  
Wide Range ◽  
Fracture Closure ◽  
Deformation Interaction

Summary Fluid flow in unpropped and natural fractures is critical in many geophysical processes and engineering applications. The flow conductivity in these fractures depends on their closure under stress, which is a complicated mechanical process that is challenging to model. The challenges come from the deformation interaction and the close coupling among the fracture geometry, pressure, and deformation, making the closure computationally expensive to describe. Hence, most of the previous models either use a small grid system or disregard deformation interaction or plastic deformation. In this study, a numerical model is developed to simulate the stress-driven closure and the conductivity for fractures with rough surfaces. The model integrates elastoplastic deformation and deformation interaction, and can handle contact between heterogeneous surfaces. Computation is optimized and accelerated by use of an algorithm that combines the conjugate-gradient (CG) method and the fast-Fourier-transform (FFT) technique. Computation time is significantly reduced compared with traditional methods. For example, a speedup of five orders of magnitude is obtained for a grid size of 512 × 512. The model is validated against analytical problems and experiments, for both elastic-only and elastoplastic scenarios. It is shown that interaction between asperities and plastic deformation cannot be ignored when modeling fracture closure. By applying our model, roughness and yield stress are found to have a larger effect on fracture closure and compliance than Young's modulus. Plastic deformation is a dominant contributor to closure and can make up more than 70% of the total closure in some shales. The plastic deformation also significantly alters the relationship between fracture stiffness and conductivity. Surfaces with reduced correlation length produce greater conductivity because of their larger apertures, despite more fracture closure. They have a similar fraction of area in contact as compared with surfaces with longer fracture length, but the pattern of area in contact is more scattered. Contact between heterogeneous surfaces with more soft minerals leads to increased plastic deformation and fracture closure, and results in lower fracture conductivity. Fracture compliance appears not to be as sensitive to the distribution pattern of hard and soft minerals. Our model compares well with experimental data for fracture closure, and can be applied to unpropped or natural fractures. These results are obtained for a wide range of conditions: surface profile following Gaussian distribution with correlation length of 50 µm and roughness of 4 to 50 µm, yield stress of 100 to 1500 MPa, and Young's modulus of 20 to 60 GPa. The results may be different for situations outside this range of parameters.

Young's modulus of trabecular and cortical bone material: Ultrasonic and microtensile measurements

1993 ◽  
Vol 26 (2) ◽  
pp. 111-119 ◽  
Author(s):  
Jae Young Rho ◽  
Richard B. Ashman ◽  
Charles H. Turner
Keyword(s):  
Cortical Bone ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Bone Material

Evaluation of Decalcification Induced Changes in Bone Strength Using Electrical Conductivity Measurements

2014 ◽  
Author(s):  
Vladislav Sevostianov
Keyword(s):  
Electrical Resistivity ◽  
Electrical Properties ◽  
Cortical Bone ◽  
Young’S Modulus ◽  
Bone Strength ◽  
Acid Treatment ◽  
Bending Strength ◽  
Young's Modulus ◽  
Testing Machine ◽  
Mechanical And Electrical Properties

The paper focuses on the effect of decalcification on microstructure and the mechanical and electrical properties of cortical bone. Decalcification is produced by placing the specimens into 5% vinegar acid for 72 hours. This acid treatment leads to a decrease in mass of the specimens 7.78 % (averaged over ten acid treated specimens). Microstructure of natural bone and acid treated bone is then compared using confocal microscopy. To estimate effect of acid treatment on electrical resistivity of bone, the specimens are rinsed and saturated with 0.9% NaCl solution for ten minutes. Then electrical resistance is measured by the four-point method and electrical resistivity is calculated. Averaging over ten acid treated specimens and ten control specimens show that decalcification lead to increase of electrical resistivity 5.85 times. Comparison of mechanical properties of natural and acid treated bones is done by three point bending using Instron 5882 testing machine. It is observed that 7.78 % mass loss in cortical bone yields reduction of the Young’s modulus about 2.7 times and bending strength of the specimens by 35%. A positive correlation between change in strength and Young’s modulus and electrical resistivity of the individual specimens is observed. The obtained results allows one to estimate changes in mechanical and electrical properties of bone from known losses in bone mass and, thus, non-destructively evaluate the decrease in bone strength through changes in electrical resistivity.

scholarly journals Osteoporosis Changes Collagen/Apatite Orientation and Young’s Modulus in Vertebral Cortical Bone of Rat

2018 ◽  
Vol 104 (4) ◽  
pp. 449-460 ◽  
Author(s):  
Ryosuke Ozasa ◽  
Takuya Ishimoto ◽  
Sayaka Miyabe ◽  
Jun Hashimoto ◽  
Makoto Hirao ◽  
...  
Keyword(s):  
Cortical Bone ◽  
Young’S Modulus ◽  
Young's Modulus

Measuring the Elastic Modulus of Small Tissue Samples

1998 ◽  
Vol 20 (1) ◽  
pp. 17-28 ◽  
Author(s):  
R.Q. Erkamp ◽  
P. Wiggins ◽  
A.R. Skovoroda ◽  
S.Y. Emelianov ◽  
M. O'Donnell
Keyword(s):  
Elastic Modulus ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Tissue Sample ◽  
Clinical Tool ◽  
Limited Sample ◽  
Element Analysis ◽  
Tissue Samples ◽  
Small Tissue ◽  
Wide Range

Independent measurements of the elastic modulus (Young's modulus) of tissue are a necessary step in turning elasticity imaging into a clinical tool. A system capable of measuring the elastic modulus of small tissue samples was developed. The system tolerates the constraints of biological tissue, such as limited sample size (≤1.5 cm3) and imperfections in sample geometry. A known deformation is applied to the tissue sample while simultaneously measuring the resulting force. These measurements are then converted to an elastic modulus, where the conversion uses prior calibration of the system with plastisol samples of known Young's modulus. Accurate measurements have been obtained from 10 to 80 kPa, covering a wide range of tissue modulus values. In addition, the performance of the system was further investigated using finite element analysis. Finally, preliminary elasticity measurements on canine kidney samples are presented and discussed.

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