Elastic constants of inflated lobes of dog lungs

1976 ◽  
Vol 40 (4) ◽  
pp. 508-513 ◽  
Author(s):  
S. J. Lai-Fook ◽  
T. A. Wilson ◽  
R. E. Hyatt ◽  
J. R. Rodarte
Keyword(s):  
Bulk Modulus ◽  
Young’S Modulus ◽  
Elastic Constants ◽  
Young's Modulus ◽  
Poisson Ratio ◽  
Inflation Pressure ◽  
Initial State ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
Indentation Tests

The elastic constants of dog lungs were determined at various degrees of inflation. In one set of experiments, the lobes were subjected to deformations that approximated the conditions of uniaxial loading. These data, together with the bulk modulus data obtained from the local slope of the pressure-volume curve, were used to determine the two elastic moduli that are needed to describe small nonuniform deformations about an initial state of uniform inflation. The bulk modulus was approximately 4 times the inflation pressure, and Young's modulus was approximately 1.5 times the inflation pressure. In a second set of experiments, lobes were subjected to indentation tests using cylindric punches 1–3 cm in diameter. The value for Young's modulus obtained from these data was slightly higher, approximately twice the inflation pressure. These experiments indicate that the lung is much more easily deformable in shear than in dilatation and that the Poisson ratio for the lung is high, approximately 0.43.

Mechanical and thermodynamics properties of Al2Ca and Mg2Ca under various pressure: A first principle study

2021 ◽  
Vol 11 (9) ◽  
pp. 1571-1578
Author(s):  
Zai Gao Huang
Keyword(s):  
Shear Modulus ◽  
Bulk Modulus ◽  
Young’S Modulus ◽  
Elastic Constants ◽  
Coefficient Of Thermal Expansion ◽  
Young's Modulus ◽  
Structural Parameters ◽  
Harmonic Approximation ◽  
Polycrystalline Materials ◽  
Ductile Phase

The mechanical and thermodynamic properties of Al2Ca and Mg2Ca in the pressure range of 0~100 Gpa were investigated using first-principles calculations. The structural parameters, such as lattice constant ratio, unit cell volume ratio, density, were investigated. The calculated elastic constants satisfy the born’s stability criterion, indicating that they are mechanically stable at normal and high pressure. Mechanical parameters such as bulk modulus, shear modulus, and Young’s modulus of polycrystalline materials have been derived from single-crystal elastic constants. The Poisson’s ratio and anisotropy were investigated. The results show that the B/G value of Mg2Ca is greater than 1.75, indicating it is a ductile phase under various pressures. When the pressure was equal to 40 Gpa, Al2Ca was transferred brittle to toughness, and the bulk modulus, shear modulus, and Young’s modulus of Al2Ca were all larger than those of Mg2Ca, indicating that the comprehensive mechanical properties of Al2Ca are better than those of Mg2Ca. The constant heat capacity obtained by the quasi-harmonic approximation indicates that the ability of Mg2Ca to release or store heat is greater than that of Al2Ca. Moreover, the coefficient of thermal expansion (α) increases exponentially at lower temperatures and linearly at higher temperatures for both alloys.

Lattice dynamical and elastic properties of BaFX (X = Cl, Br and I): Matlockite structure compounds

2019 ◽  
Vol 33 (20) ◽  
pp. 1950221 ◽  
Author(s):  
A. K. Kushwaha ◽  
S. Akbudak ◽  
A. C. Yadav ◽  
Ş. Uğur ◽  
G. Uğur
Keyword(s):  
Shear Modulus ◽  
Bulk Modulus ◽  
Young’S Modulus ◽  
Elastic Constants ◽  
Phonon Mode ◽  
Young's Modulus ◽  
Nearest Neighbors ◽  
Crystallographic Direction ◽  
Theoretical Results ◽  
Rigid Ion Model

In this study, an eleven-parameter rigid-ion model (RIM) is proposed for BaFX (X = Cl, Br and I) matlockite structure compounds. The interatomic interactions up to fourth nearest neighbors for the studied compounds are calculated. The zone-center raman and infrared phonon mode frequencies, elastic constants, bulk modulus B, shear modulus G, Young’s modulus E, Poisson’s coefficient, Debye temperature and sound velocity along [100], [110] and [001] directions have been calculated. It is observed that the studied BaFCl, BaFBr and BaFI compounds are stiffer in [100] direction than [001] crystallographic direction and the bulk modulus, shear modulus and Young’s modulus of the studied compounds decrease in the order of BaFCl [Formula: see text] BaFBr [Formula: see text] BaFI. The obtained results are compared with the theoretical and experimental results. It is observed that the obtained results agree very well with the experimental and theoretical results available in the literature.

Tension-induced mechanical properties of stanene

2016 ◽  
Vol 30 (12) ◽  
pp. 1650146 ◽  
Author(s):  
Lele Tao ◽  
Chuanghua Yang ◽  
Liyuan Wu ◽  
Lihong Han ◽  
Yuxin Song ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Elastic Constants ◽  
First Principles ◽  
Young's Modulus ◽  
Poisson Ratio ◽  
Group Iv ◽  
First Principles Calculations ◽  
Stress Strain Relation ◽  
Group Iv Elements ◽  
Internal Atom

In this paper, elastic properties of stanene under equiaxial or uniaxial tensions along armchair and zigzag directions are investigated by first-principles calculations. The stress–strain relation is calculated and the relaxation of the internal atom positions is analyzed. The high-order elastic constants are calculated by fitting the polynomial expressions. The Young’s modulus and Poisson ratio of the stanene is calculated to be 24.14 N/m and 0.39 N/m, respectively. The stanene exhibits lower Young’s modulus than those of the proceeding group IV elements, which is attributed to the smaller [Formula: see text]–[Formula: see text] bond energy in stanene than those of silicene and germanene. Calculated values of ultimate stresses and strains, second-order elastic constants (SOCEs) and the in-plane Young’s modulus are all positive. It proves that stanene is mechanically stable.

Elastic constants of trapped lung parenchyma

1978 ◽  
Vol 44 (6) ◽  
pp. 853-858 ◽  
Author(s):  
S. J. Lai-Fook ◽  
R. E. Hyatt ◽  
J. R. Rodarte
Keyword(s):  
Shear Modulus ◽  
Young’S Modulus ◽  
Elastic Constants ◽  
Young's Modulus ◽  
Indentation Test ◽  
Lung Parenchyma ◽  
Accurate Estimate ◽  
The Other ◽  
Indentation Tests ◽  
Trapped Lung

Isolated dog lobes were maximally trapped with air, and their parenchymal elastic properties were measured at the trapped volume. Indentation tests were performed on the surface of the lobes, followed by uniaxial and torsion tests on excised pieces of parenchyma. Similar values for Young's modulus were obtained from the indentation and uniaxial tests. The values for the shear modulus from the torison tests also were consistent with Young's modulus measured by the other procedures. The indentation test provided an accurate estimate of Young's modulus or the shear modulus for trapped lobes, and the results suggest that it is a valid method for estimating these constants in nontrapped lobes.

Relaxor Single-Crystal Plates with Nano-Size Ferroelectric Domains Applying to Ultrasonic Prove for Medical Uses

2016 ◽  
Vol 102 ◽  
pp. 57-64
Author(s):  
Toshio Ogawa ◽  
Taiki Ikegaya
Keyword(s):  
Bulk Modulus ◽  
Single Crystal ◽  
Grain Boundaries ◽  
Single Crystals ◽  
Young’S Modulus ◽  
Elastic Constants ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Poisson's Ratio ◽  
Domain Alignment

Sound velocities were measured in relaxor single-crystal plates, included in piezoelectric transducers for medical uses, using an ultrasonic precision thickness gauge with high-frequency pulse generation. The velocities were compared with the ones of piezoelectric ceramics in order to clarify characteristics of the single crystals. Estimating the difference in the sound velocities and elastic constants in the single crystals and ceramics, it was possible to evaluate effects of domain and grain boundaries on elastic constants. Existence of domain boundaries in single crystal affected the decrease in Young’s modulus, rigidity, Poisson’s ratio and bulk modulus. While existence of grain boundaries affected the decrease in Young’s modulus and rigidity, Poisson’s ratio and bulk modulus increased. It was thought these phinomina come from domain alignment by DC poling, and both the boundaries act as to absorb mechanical stress by defects due to the boundaries. In addition, the origin of piezoelectricity in single crystals is caused by low bulk modulus and Poisson’s ratio, and high Young’s modulus and rigidity in comparison with ceramics. On the contrary, the origin of piezoelectricity in ceramics is caused by high Poisson’s ratio by high bulk modulus, and furthermore, low Young’s modulus and rigidity due to domain alignment.

scholarly journals Effects of age on elastic moduli of human lungs

2000 ◽  
Vol 89 (1) ◽  
pp. 163-168 ◽  
Author(s):  
Stephen J. Lai-Fook ◽  
Robert E. Hyatt
Keyword(s):  
Shear Modulus ◽  
Bulk Modulus ◽  
Elastic Moduli ◽  
Elastic Continuum ◽  
Shear Moduli ◽  
Volume Curve ◽  
Human Lungs ◽  
Pressure Volume Curve ◽  
Indentation Tests ◽  
Lung Deformation

The model of the lung as an elastic continuum undergoing small distortions from a uniformly inflated state has been used to describe many lung deformation problems. Lung stress-strain material properties needed for this model are described by two elastic moduli: the bulk modulus, which describes a uniform inflation, and the shear modulus, which describes an isovolume deformation. In this study we measured the bulk modulus and shear modulus of human lungs obtained at autopsy at several fixed transpulmonary pressures (Ptp). The bulk modulus was obtained from small pressure-volume perturbations on different points of the deflation pressure-volume curve. The shear modulus was obtained from indentation tests on the lung surface. The results indicated that, at a constant Ptp, both bulk and shear moduli increased with age, and the increase was greater at higher Ptp values. The micromechanical basis for these changes remains to be elucidated.

First principles calculation of the elastic constants of intermetallic compounds: metastable Al3Li

1991 ◽  
Vol 6 (2) ◽  
pp. 324-329 ◽  
Author(s):  
X-Q. Guo ◽  
R. Podloucky ◽  
A.J. Freeman
Keyword(s):  
Young’S Modulus ◽  
Elastic Constants ◽  
First Principles ◽  
Local Density ◽  
Young's Modulus ◽  
Poisson Ratio ◽  
First Principles Calculation ◽  
Full Potential ◽  
A Value ◽  
Experimental Values

We report first principles local density calculations for the metastable Al3Li intermetallic compound with cubic L12 crystal structure using the full-potential linearized augmented plane wave method. From the second derivative of the total energy as a function of volume, and generated tetragonal and trigonal lattice distortions, the elastic constants C11, C12, and C44 were derived yielding C11 = 158 GPa, C12 = 29.4 GPa, and C44 = 57.7 GPa. Because of the very high Young's modulus (E = 141 GPa) compared, for example, to pure Al (E = 66 GPa), it is suggested that Al3Li plays an important role in strengthening the Al–Li alloys. The calculated Young's modulus appears in good agreement with experimental estimates when the experimental values are extrapolated to 0 K. Although the Young's modulus of Al3Li is increased in comparison to Al, the calculated bulk modulus is decreased to a value of 72 GPa as compared to pure Al (82 GPa), in agreement with experiment. As a result, the Poisson ratio is reduced to ŝ = 0.173 as compared to the value 1/3 for an isotropic medium. Because of this and the high Young's modulus, the calculated Debye temperature ΘD at 0 K amounts to 672 K, which is substantially larger than ΘD for Al, which is about 400 K.

A dynamical method for the determination of Young's modulus by stretching

1928 ◽  
Vol 24 (2) ◽  
pp. 276-279
Author(s):  
C. F. Sharman
Keyword(s):  
Young’S Modulus ◽  
Elastic Constants ◽  
Young's Modulus ◽  
The Other ◽  
Static Deformation ◽  
Elastic Forces ◽  
Dynamical Method ◽  
Period Of Oscillation

There are two general methods of measuring the elastic constants of bodies; one involves a study of the static deformation produced by the appropriate kind of stress, and the other a measurement of the period of oscillation of a system of known inertia under the elastic forces.

Indentation Tests for Sintered Silver in Die-Attach Interconnection After Thermal Cycling

2021 ◽  
Author(s):  
Fei Qin ◽  
Shuai Zhao ◽  
Yanwei Dai ◽  
Lingyun Liu ◽  
Tong An ◽  
...  
Keyword(s):  
Thermal Cycling ◽  
Young’S Modulus ◽  
Mechanical Performance ◽  
Young's Modulus ◽  
Silver Layer ◽  
Thermal Cycles ◽  
Nano Indentation ◽  
Die Attach ◽  
Indentation Tests ◽  
Sintered Silver

Abstract Thermo-mechanical reliability assessment for sintered silver is a crucial issue as sintered silver is a promising candidate of die-attachment materials for power devices. In this paper, the nano-indentation tests are performed for sintered silver in typical die-attach interconnection under different thermal cycles. Based on thermal cycling test, the Young's modulus and hardness of sintered silver layer have been presented. It is found that the Young's modulus and hardness of sintered silver layer changes slightly although the microstructure of sintered silver also presents some variations. The stress and strain curves for different thermal cycling tests for sintered silver based on reverse analysis of nano-indentation are also given. The results show that the elastoplastic constitutive equations change significantly after thermal cycling tests, and the yielding stress decreases remarkably after 70 thermal cycles. The experimental investigation also show that the cracking behaviors of sintered silver depends on its geometry characteristics, which implies that the possible optimization of sintered silver layer could enhance its thermo-mechanical performance.

Sign in / Sign up

Export Citation Format

Share Document