Determining the optimum elastic modulus and Poisson’s ratio for an endodontic prefabricated post

2016 ◽  
pp. 269-272 ◽  
Keyword(s):  
Elastic Modulus ◽  
Poisson’S Ratio ◽  
Poisson's Ratio

The Model for Calculating Elastic Modulus and Poisson's Ratio of Coal Body

2013 ◽  
Vol 6 (1) ◽  
pp. 36-43 ◽  
Author(s):  
Ai Chi ◽  
Li Yuwei
Keyword(s):  
Elastic Modulus ◽  
Poisson’S Ratio ◽  
Fractured Rock ◽  
Rock Block ◽  
Poisson's Ratio ◽  
Linear Elastic ◽  
Study Results ◽  
The Face ◽  
Block Face ◽  
Coal Rock

Coal body is a type of fractured rock mass in which lots of cleat fractures developed. Its mechanical properties vary with the parametric variation of coal rock block, face cleat and butt cleat. Based on the linear elastic theory and displacement equivalent principle and simplifying the face cleat and butt cleat as multi-bank penetrating and intermittent cracks, the model was established to calculate the elastic modulus and Poisson's ratio of coal body combined with cleat. By analyzing the model, it also obtained the influence of the parameter variation of coal rock block, face cleat and butt cleat on the elastic modulus and Poisson's ratio of the coal body. Study results showed that the connectivity rate of butt cleat and the distance between face cleats had a weak influence on elastic modulus of coal body. When the inclination of face cleat was 90°, the elastic modulus of coal body reached the maximal value and it equaled to the elastic modulus of coal rock block. When the inclination of face cleat was 0°, the elastic modulus of coal body was exclusively dependent on the elastic modulus of coal rock block, the normal stiffness of face cleat and the distance between them. When the distance between butt cleats or the connectivity rate of butt cleat was fixed, the Poisson's ratio of the coal body initially increased and then decreased with increasing of the face cleat inclination.

Research on dynamic characteristics of gear system considering the influence of temperature on material performance

2021 ◽  
pp. 107754632110026
Author(s):  
Zhou Sun ◽  
Siyu Chen ◽  
Xuan Tao ◽  
Zehua Hu
Keyword(s):  
Elastic Modulus ◽  
Dynamic Characteristics ◽  
Poisson’S Ratio ◽  
Gear System ◽  
Poisson's Ratio ◽  
Effect Of Temperature ◽  
Time Varying ◽  
Influence Of Temperature ◽  
Meshing Stiffness ◽  
Influence Of Temperature On

Under high-speed and heavy-load conditions, the influence of temperature on the gear system is extremely important. Basically, the current work on the effect of temperature mostly considers the flash temperature or the overall temperature field to cause expansion at the meshing point and then affects nonlinear factors such as time-varying meshing stiffness, which lead to the deterioration of the dynamic transmission. This work considers the effect of temperature on the material’s elastic modulus and Poisson’s ratio and relates the temperature to the time-varying meshing stiffness. The effects of temperature on the elastic modulus and Poisson’s ratio are expressed as functions and brought into the improved energy method stiffness calculation formula. Then, the dynamic characteristics of the gear system are analyzed. With the bifurcation diagram, phase, Poincaré, and fast Fourier transform plots of the gear system, the influence of temperature on the nonlinear dynamics of the gear system is discussed. The numerical analysis results show that as the temperature increases, the dynamic response of the system in the middle-speed region gradually changes from periodic motion to chaos.

Measurement of Cement in Situ Stresses and Mechanical Properties Without Cooling or Depressurization

2021 ◽  
Author(s):  
Meng Meng ◽  
Luke Frash ◽  
James Carey ◽  
Wenfeng Li ◽  
Nathan Welch ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Elastic Modulus ◽  
Poisson’S Ratio ◽  
Axial Stress ◽  
Triaxial Compression ◽  
In Situ Measurement ◽  
Poisson's Ratio ◽  
Ambient Conditions

Abstract Accurate characterization of oilwell cement mechanical properties is a prerequisite for maintaining long-term wellbore integrity. The drawback of the most widely used technique is unable to measure the mechanical property under in situ curing environment. We developed a high pressure and high temperature vessel that can hydrate cement under downhole conditions and directly measure its elastic modulus and Poisson's ratio at any interested time point without cooling or depressurization. The equipment has been validated by using water and a reasonable bulk modulus of 2.37 GPa was captured. Neat Class G cement was hydrated in this equipment for seven days under axial stress of 40 MPa, and an in situ measurement in the elastic range shows elastic modulus of 37.3 GPa and Poisson's ratio of 0.15. After that, the specimen was taken out from the vessel, and setted up in the triaxial compression platform. Under a similar confining pressure condition, elastic modulus was 23.6 GPa and Possion's ratio was 0.26. We also measured the properties of cement with the same batch of the slurry but cured under ambient conditions. The elastic modulus was 1.63 GPa, and Poisson's ratio was 0.085. Therefore, we found that the curing condition is significant to cement mechanical property, and the traditional cooling or depressurization method could provide mechanical properties that were quite different (50% difference) from the in situ measurement.

Elasto-Plastic Hemispherical Contact Models for Various Mechanical Properties

2005 ◽  
Author(s):  
John J. Quicksall ◽  
Robert L. Jackson ◽  
Itzhak Green
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Material Properties ◽  
Poisson’S Ratio ◽  
Carbon Steels ◽  
Poisson's Ratio ◽  
Aluminum Bronze ◽  
Contact Models ◽  
Element Technique ◽  
Malleable Cast

This work uses the finite element technique to model the elasto-plastic deformation of a hemisphere contacting a rigid flat for various material properties typical of aluminum, bronze, copper, titanium and malleable cast iron. Additionally, this work conducted parametric FEM tests on a generic material in which the elastic modulus and Poisson’s ratio are varied independently while the yield strength is held constant. A larger spectrum of material properties are covered in this work than in most previous works. The results are compared to two previously formulated elasto-plastic models simulating the deformation of a hemisphere in contact with a rigid flat. Both of the previously formulated models use carbon steel mechanical properties to arrive at empirical formulations implied to pertain to various materials. While both models considered several carbon steels with varying yield strengths, they did not test materials with varying Poisson’s ratio or elastic modulus. The previously generated elasto-plastic models give fairly good predictions when compared to the FEM results for various material properties from the current work, except that one model produces more accurate predictions overall, especially at large deformations where other models neglect important trends due to decreases in “hardness” with increasing deformation.

Biomimetic composites inspired by venous leaf

2017 ◽  
Vol 52 (3) ◽  
pp. 361-372 ◽  
Author(s):  
Gongdai Liu ◽  
R Ghosh ◽  
A Vaziri ◽  
A Hossieni ◽  
D Mousanezhad ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Yield Stress ◽  
Poisson’S Ratio ◽  
Composite Structures ◽  
Volume Fraction ◽  
Matrix Material ◽  
Poisson's Ratio ◽  
Fiber Volume ◽  
Young’S Moduli

A typical plant leaf can be idealized as a composite having three principal fibers: the central mid-fiber corresponding to the mid-rib, straight parallel secondary fibers attached to the mid-fiber representing the secondary veins, and then another set of parallel fibers emanating from the secondary fibers mimicking the tertiary fibers embedded in a matrix material. This paper introduces a biomimetic composite design inspired by the morphology of venous leafs and investigates the effects of venation morphologies on the in-plane mechanical properties of the biomimetic composites using finite element method. The mechanical properties such as Young’s moduli, Poisson’s ratio, and yield stress under uniaxial loading of the resultant composite structures was studied and the effect of different fiber architectures on these properties was investigated. To this end, two broad types of architectures were used both having similar central main fiber but differing in either having only secondary fibers or additional tertiary fibers. The fiber and matrix volume fractions were kept constant and a comparative parametric study was carried out by varying the inclination of the secondary fibers. The results show that the elastic modulus of composite in the direction of main fiber increases linearly with increasing the angle of the secondary fibers. Furthermore, the elastic modulus is enhanced if the secondary fibers are closed, which mimics composites with closed cellular fibers. In contrast, the elastic modulus of composites normal to the main fiber ( x direction) exponentially decreases with the increase of the angle of the secondary fibers and it is little affected by having secondary fibers closed. Similar results were obtained for the yield stress of the composites. The results also indicate that Poisson’s ratio linearly increases with the secondary fiber angle. The results also show that for a constant fiber volume fraction, addition of various tertiary fibers may not significantly enhance the mechanical properties of the composites. The mechanical properties of the composites are mainly dominated by the secondary fibers. Finally, a simple model was proposed to predict these behaviors.

scholarly journals Experimental Research on the Mechanical Characteristics and the Failure Mechanism of Coal-Rock Composite under Uniaxial Load

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Ke Yang ◽  
Zhen Wei ◽  
Xiaolou Chi ◽  
Yonggang Zhang ◽  
Litong Dou ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Acoustic Emission ◽  
Elastic Modulus ◽  
Crack Propagation ◽  
Failure Mechanism ◽  
Poisson’S Ratio ◽  
Mechanical Characteristics ◽  
Poisson's Ratio ◽  
Energy Value ◽  
Coal Rock

Due to the influence of the component structure and combination modes, the mechanical characteristics and failure modes of the coal-rock composite show different characteristics from the monomer. In order to explore the effect of different coal-rock ratios on the deformation and the failure law of the combined sample, the RMT rock mechanics test system and acoustic emission real-time monitoring system are adopted to carry out uniaxial compression tests on coal, sandstone, and three kinds of combined samples. The evolution rules of the mechanical parameters of the combined samples, such as the uniaxial compressive strength, elastic modulus, and Poisson’s ratio, are obtained. The expansion and failure deformation characteristics of the combined sample are analyzed. Furthermore, the evolution laws of the fractal and acoustic emission signals are combined to reveal the crack propagation and failure mechanism of the combined samples. The results show that the compressive strength and elastic modulus of the combined sample increase with the decrease of the coal-rock ratios, and Poisson’s ratio decreases with the decrease of the coal-rock ratios. The strain softening weakens at the postpeak stage, which shows an apparent brittle failure. The combined sample of coal and sandstone has different degrees of damages under load. The coal is first damaged with a high degree of breakage, with obvious tensile failure. The acoustic emission energy value presents different stage characteristics with increasing load. Crackling sound occurs in the destroy section before the sample reaches the peak, along with small coal block ejection and the partial destruction. The energy value fluctuates violently, with the appearance of several peaks. At the postpeak stage, the coal samples expand rapidly with a loud crackling sound in the destroy section, and the energy value increases dramatically. The crack propagation induces the damage in the sandstone; when the energy reaches the limit value, the instantaneous release of elastic energy leads to the overall structural instability.

Biaxial elastic properties of rat arteries in vivo: influence of vascular wall cells on anisotropy

1994 ◽  
Vol 267 (2) ◽  
pp. H574-H579 ◽  
Author(s):  
G. J. L'Italien ◽  
N. R. Chandrasekar ◽  
G. M. Lamuraglia ◽  
W. C. Pevec ◽  
S. Dhara ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Poisson’S Ratio ◽  
Carotid Arteries ◽  
Cell Function ◽  
Vascular Wall ◽  
Poisson's Ratio ◽  
Vascular Cell ◽  
Longitudinal Modulus ◽  
Nonlinearly Elastic

There is no consensus as to the degree of arterial anisotropy or to its relationship to vascular cell function. Given the relevance of the isotropic assumption in formulating elasticity models, reliable measures of biaxial displacements are needed. In this study, a video motion analyzer (VMA) was used to describe the biaxial in vivo dynamic elasticity of 22 carotid arteries and 5 abdominal aortas in 27 rats. The influence of vascular cell function was also examined by subjecting six rats to a photosensitive drug, chloroaluminum sulfonated phthalocyanine (CASPc), which is focally cytotoxic on activation by laser. Circumferential compliance (Ccirc) was greater than longitudinal compliance (Clong) for all vessels. Compliance pressure curves were nonlinear, and biaxial displacements were in phase. The circumferential elastic modulus was less than the longitudinal modulus at common stresses. CASPc + laser reduced Ccirc but not Clong, thus altering Poisson's ratio. In conclusion, rat arteries are biaxially, nonlinearly elastic and anisotropic in vivo. Vascular cells modulate Poisson's ratio by influencing Ccirc.

Study on a New Testing Method of the Elastic Modulus and Poisson's Ratio by Using Brazilian Disk Test

2013 ◽  
Vol 347-350 ◽  
pp. 1199-1202
Author(s):  
Fei Wu ◽  
Shi Ming Dong
Keyword(s):  
Elastic Modulus ◽  
Poisson’S Ratio ◽  
Vertical Direction ◽  
Test Method ◽  
Poisson's Ratio ◽  
Theoretical Formula ◽  
Brazilian Disk ◽  
Total Displacement ◽  
The Relationship ◽  
Poissons Ratio

In order to develop a new test method of the elastic modulus and Poissons ratio, based on the theoretical analysis of the Brazilian disk diametrically loaded by a pair of forces, the relationship is obtained between the total displacement of one point on the vertical direction of the load line and the applied force as well as the elastic modulus and Poissons ratio. The strain gauges with different length are used to measure the displacement of the corresponding point, and then the displacement is employed to calculate the elastic modulus and Poisson's ratio by using the theoretical formula. The proposed method can provide a new approach to estimate the elastic modulus and Poissons ratio by using Brazilian disk splitting tests.

Experimental Determination of the Poisson's Ratio and the Elastic Modulus of a Sand-Plastic Composite Material

2017 ◽  
Vol 6 (6) ◽  
pp. 292 ◽  
Author(s):  
Moro Olivier Boffoue ◽  
Brahiman Traore ◽  
Conand Honoré Kouakou ◽  
Kokou Esso Atcholi ◽  
Remy Lachat ◽  
...  
Keyword(s):  
Composite Material ◽  
Elastic Modulus ◽  
Experimental Determination ◽  
Poisson’S Ratio ◽  
Poisson's Ratio ◽  
Plastic Composite
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