scholarly journals A Quasi-Static Quantitative Ultrasound Elastography Algorithm Using Optical Flow

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3010
Author(s):  
Raphael Lamprecht ◽  
Florian Scheible ◽  
Marion Semmler ◽  
Alexander Sutor
Keyword(s):  
Optical Flow ◽  
Young’S Modulus ◽  
Elastic Properties ◽  
Young's Modulus ◽  
Image Data ◽  
Maximum Error ◽  
Ultrasound Elastography ◽  
Static Compression ◽  
Tissue Properties ◽  
A Performance

Ultrasound elastography is a constantly developing imaging technique which is capable of displaying the elastic properties of tissue. The measured characteristics could help to refine physiological tissue models, but also indicate pathological changes. Therefore, elastography data give valuable insights into tissue properties. This paper presents an algorithm that measures the spatially resolved Young’s modulus of inhomogeneous gelatin phantoms using a CINE sequence of a quasi-static compression and a load cell measuring the compressing force. An optical flow algorithm evaluates the resulting images, the stresses and strains are computed, and, conclusively, the Young’s modulus and the Poisson’s ratio are calculated. The whole algorithm and its results are evaluated by a performance descriptor, which determines the subsequent calculation and gives the user a trustability index of the modulus estimation. The algorithm shows a good match between the mechanically measured modulus and the elastography result—more precisely, the relative error of the Young’s modulus estimation with a maximum error 35%. Therefore, this study presents a new algorithm that is capable of measuring the elastic properties of gelatin specimens in a quantitative way using only the image data. Further, the computation is monitored and evaluated by a performance descriptor, which measures the trustability of the results.

scholarly journals A parametric prediction of the Young’s modulus of polymers enhanced with ΜWCNTs

2018 ◽  
Vol 233 ◽  
pp. 00025
Author(s):  
P.V. Polydoropoulou ◽  
K.I. Tserpes ◽  
Sp.G. Pantelakis ◽  
Ch.V. Katsiropoulos
Keyword(s):  
Young’S Modulus ◽  
Elastic Properties ◽  
Young's Modulus ◽  
Experimental Results ◽  
Scale Model ◽  
Fe Model ◽  
Multi Scale ◽  
Unit Cells ◽  
Random Dispersion

In this work a multi-scale model simulating the effect of the dispersion, the waviness as well as the agglomerations of MWCNTs on the Young’s modulus of a polymer enhanced with 0.4% MWCNTs (v/v) has been developed. Representative Unit Cells (RUCs) have been employed for the determination of the homogenized elastic properties of the MWCNT/polymer. The elastic properties computed by the RUCs were assigned to the Finite Element (FE) model of a tension specimen which was used to predict the Young’s modulus of the enhanced material. Furthermore, a comparison with experimental results obtained by tensile testing according to ASTM 638 has been made. The results show a remarkable decrease of the Young’s modulus for the polymer enhanced with aligned MWCNTs due to the increase of the CNT agglomerations. On the other hand, slight differences on the Young’s modulus have been observed for the material enhanced with randomly-oriented MWCNTs by the increase of the MWCNTs agglomerations, which might be attributed to the low concentration of the MWCNTs into the polymer. Moreover, the increase of the MWCNTs waviness led to a significant decrease of the Young’s modulus of the polymer enhanced with aligned MWCNTs. The experimental results in terms of the Young’s modulus are predicted well by assuming a random dispersion of MWCNTs into the polymer.

scholarly journals High-Temperature Elastic Properties of Yttrium-Doped Barium Zirconate

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 968
Author(s):  
Fumitada Iguchi ◽  
Keisuke Hinata
Keyword(s):  
High Temperature ◽  
Young’S Modulus ◽  
Elastic Properties ◽  
Measurement Method ◽  
Young's Modulus ◽  
Barium Zirconate ◽  
Shear Moduli ◽  
Ceramic Fuel ◽  
Yttrium Concentration ◽  
Ceramic Fuel Cells

The elastic properties of 0, 10, 15, and 20 mol% yttrium-doped barium zirconate (BZY0, BZY10, BZY15, and BZY20) at the operating temperatures of protonic ceramic fuel cells were evaluated. The proposed measurement method for low sinterability materials could accurately determine the sonic velocities of small-pellet-type samples, and the elastic properties were determined based on these velocities. The Young’s modulus of BZY10, BZY15, and BZY20 was 224, 218, and 209 GPa at 20 °C, respectively, and the values decreased as the yttrium concentration increased. At high temperatures (>20 °C), as the temperature increased, the Young’s and shear moduli decreased, whereas the bulk modulus and Poisson’s ratio increased. The Young’s and shear moduli varied nonlinearly with the temperature: The values decreased rapidly from 100 to 300 °C and gradually at temperatures beyond 400 °C. The Young’s modulus of BZY10, BZY15, and BZY20 was 137, 159, and 122 GPa at 500 °C, respectively, 30–40% smaller than the values at 20 °C. The influence of the temperature was larger than that of the change in the yttrium concentration.

Elastic properties and breaking strengths of GaS, GaSe and GaTe nanosheets

Nanoscale ◽  
2018 ◽  
Vol 10 (27) ◽  
pp. 13022-13027 ◽  
Author(s):  
Basant Chitara ◽  
Assaf Ya'akobovitz
Keyword(s):  
Atomic Force Microscopy ◽  
Young’S Modulus ◽  
Elastic Properties ◽  
Young's Modulus ◽  
Force Microscopy ◽  
Atomic Force ◽  
Maximal Strain

The present study highlights the elastic properties of suspended GaS, GaSe and GaTe nanosheets using atomic force microscopy. GaS exhibited the highest Young's modulus (∼173 GPa) among these nanosheets. These materials can withstand maximal stresses of up to 8 GPa and a maximal strain of 7% before breaking, making them suitable for stretchable electronic and optomechanical devices.

Single-walled carbon nanotubes functionalized by a series of dichlorocarbenes: DFT study

2016 ◽  
Vol 30 (08) ◽  
pp. 1650118 ◽  
Author(s):  
Igor K. Petrushenko ◽  
Konstantin B. Petrushenko
Keyword(s):  
Carbon Nanotubes ◽  
Young’S Modulus ◽  
Elastic Properties ◽  
Density Functional ◽  
Young's Modulus ◽  
Strong Dependence ◽  
Single Walled Carbon Nanotubes ◽  
Binding Energies ◽  
Single Walled Carbon ◽  
Walled Carbon Nanotubes

The structural and elastic properties of neutral and ionized dichlorocarbene (CCl2) functionalized single-walled carbon nanotubes (SWCNTs) were studied using density functional theory (DFT). The Young’s modulus of ionized pristine SWCNTs is found to decrease in comparison to that of neutral models. The interesting effect of increase in Young’s modulus values of ionized functionalized SWCNTs is observed. We ascribe this feature to the concurrent processes of the bond elongation on ionization and the local deformation on cycloaddition. The strong dependence of the elasticity modulus on the number of addends is also observed. However, the CCl2-attached SWCNTs in their neutral and ionized forms remain strong enough to be suitable for the reinforcement of composites. In contrast to the elastic properties, the binding energies do not change significantly, irrespective of CCl2 coverage.

Fibers of Bamboo and Hem Palm Tree

2001 ◽  
Vol 702 ◽  
Author(s):  
Shigeyasu Amada
Keyword(s):  
Young’S Modulus ◽  
Elastic Properties ◽  
Volume Fraction ◽  
Young's Modulus ◽  
Simple Procedure ◽  
High Strength ◽  
Tensile Tests ◽  
Palm Tree ◽  
Bamboo Fibers ◽  
The One

ABSTRACTBamboo is a typical composite material which is axially reinforced by very strong fibers. So that, the fibers play an important role for the bamboo structure. The elastic properties of the bamboo culm have been measured only by tensile test so far, which needs a large specimen. Recently ultra-sonic technique, which has a simple procedure and uses a small specimen, has been applied to woods as well as metals. This report reviews about the elastic properties of bamboo and Hemp palm fibers. The Young's modulus and Poisson's ratio of the bamboo fibers are measured by ultra-sonic method with a transmitting wave. On the other hand, the strength of the bamboo and Hemp palm fibers are measured by the tensile tests. Using the volume fraction of fibers in the specimen and mixture principle, the Young's modulus and strength of the fibers and parenchyma were obtained. The fiber has a high strength up to 1GPa and an strong anisotropic property because its axial Young's modulus has 7 times higher than the one in the transverse direction.

Elastic Properties and Structural Evolution of AgNi Superlattices

1991 ◽  
Vol 229 ◽  
Author(s):  
B. Rodmacq ◽  
V. Pelosin ◽  
J. Hillairet
Keyword(s):  
Young’S Modulus ◽  
Elastic Properties ◽  
Young's Modulus ◽  
Functional Dependence ◽  
Structural Evolution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Tension Tests ◽  
Prepared State ◽  
Dimensional Variation

AbstractSilver-nickel multilayers were prepared by sputtering at 100 K. X-ray diffraction, electrical resistivity and dimensional variation measurements were performed to structurally characterize these stratified materials, both in the as-prepared state and during the course of annealing cycles. Clearly, polycrystalline superlattices with marked (111) texture perpendicular to the strata are formed. We studied the elastic properties of these superlattices by performing uniaxial tension tests. No deviation from linear elasticity was observed, whatever the period. Young's modulus was found to be 130±15 GPa for all the periods studied. Thus no significant functional dependence of Young's modulus on the stacking periodicity exists in the AgNi superlattice, in the range of periods explored, 2.6 to 18 nm.

scholarly journals Evaluation of the effectiveness of representative methods for determining Young's modulus and hardness from instrumented indentation data

2006 ◽  
Vol 21 (1) ◽  
pp. 225-233 ◽  
Author(s):  
Dejun Ma ◽  
Taihua Zhang ◽  
Chung Wo Ong
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Maximum Error ◽  
Instrumented Indentation ◽  
Modulus Ratio ◽  
Material Parameters ◽  
Correction Scheme ◽  
Single Standard ◽  
Hardness Values ◽  
Hardening Coefficient

The effectiveness of Oliver & Pharr's (O&P's) method, Cheng & Cheng's (C&C’s) method, and a new method developed by our group for estimating Young's modulus and hardness based on instrumented indentation was evaluated for the case of yield stress to reduced Young's modulus ratio (σy/Er) ≥ 4.55 × 10−4 and hardening coefficient (n) ≤ 0.45. Dimensional theorem and finite element simulations were applied to produce reference results for this purpose. Both O&P's and C&C's methods overestimated the Young's modulus under some conditions, whereas the error can be controlled within ±16% if the formulation was modified with appropriate correction functions. Similar modification was not introduced to our method for determining Young's modulus, while the maximum error of results was around ±13%. The errors of hardness values obtained from all the three methods could be even larger and were irreducible with any correction scheme. It is therefore suggested that when hardness values of different materials are concerned, relative comparison of the data obtained from a single standard measurement technique would be more practically useful. It is noted that the ranges of error derived from the analysis could be different if different ranges of material parameters σy/Er and n are considered.

The Effect of Nitrogen Doping on the Elastic Properties of Silicene

2015 ◽  
Vol 245 ◽  
pp. 14-18
Author(s):  
Mary A. Chibisova ◽  
Andrey N. Chibisov
Keyword(s):  
Density Functional Theory ◽  
Bulk Modulus ◽  
Young’S Modulus ◽  
Elastic Properties ◽  
Density Functional ◽  
Nitrogen Doping ◽  
Young's Modulus ◽  
Functional Theory ◽  
Nitrogen Doped

This paper deals with the elastic properties of pure and nitrogen-doped silicene using density functional theory. During the compression (tension) from –2 to 2 GPa of pure and nitrogen-doped silicene, the corresponding values for the bulk modulus are obtained. It is found that the doping of the silicene structure with nitrogen has practically no effect on the value of its bulk modulus. However, the Young's modulus is increased of about 1.25 times.

Analysis of the Scatter of the Elastic Properties in Conventionally Cast Nickel Base Superalloys: Quantification, Modeling and Evaluation of the Impact on Gas Turbine Blade Design

2014 ◽  
Author(s):  
Andrea Riva ◽  
Andrea Bessone
Keyword(s):  
Gas Turbine ◽  
Young’S Modulus ◽  
Elastic Properties ◽  
Young's Modulus ◽  
Turbine Blades ◽  
Mode Shapes ◽  
Elastic Behavior ◽  
Nickel Base Superalloys ◽  
Nickel Base ◽  
The Impact

Cast nickel-base superalloys elastic properties have a very large scatter, mainly because of the coarse grain microstructure and in-grain anisotropy. This high dispersion must be taken into account in the design of gas turbine blades, in particular when evaluating phenomena directly linked to the elastic behavior, such as blades vibration. This source of elastic properties scatter becomes even more important on specimens for material characterization because of their inferior size, which entails a lesser number of grains (i.e. a larger scatter). In this paper a model aimed to quantify such scatter is proposed. The performances of the model in predicting the standard deviation of the Young’s modulus (and consequently of the eigenfrequencies) are also shown, both for tested specimens and blades excited on clamps. Finally, a sensitivity FEM modal analysis is performed in order to evaluate how the elastic property dispersion might affect the blade eigenfrequencies and the relative mode shapes, with particular emphasis on the case of a specific region of a geometrically complex component affected by an anomalous Young’s modulus. Besides, the influence of the blade mass is evaluated through both experimental clamp impact tests and FEM analyses. The effect on blades of such source of scatter is then compared to the effect of the elastic properties dispersion. ANSYS program has been used for the simulations.

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