Experimental Study on the Influence of Temperature on Shale Mechanical Properties under Conventional Triaxial Compression

2011 ◽  
Vol 250-253 ◽  
pp. 1452-1455 ◽  
Author(s):  
Lu Bo Meng ◽  
Tian Bin Li ◽  
Liang Wen Jiang ◽  
Hong Min Ma
Keyword(s):  
Mechanical Properties ◽  
Thermal Stress ◽  
Elastic Modulus ◽  
High Temperature ◽  
Poisson’S Ratio ◽  
Triaxial Compression ◽  
Poisson's Ratio ◽  
Influence Of Temperature ◽  
Conventional Triaxial Compression ◽  
Influence Of Temperature On

High temperature conventional triaxial compression test of shale are carried out by the MTS815 servo-controlled testing machine, based on the experimental results, the relationships between temperature and shale peak strength, elastic modulus, Poisson's ratio, cohesion, internal friction angle are investigated. Although the experimental results are discrete comparatively, the general law is obvious. When the confining pressure imposed on shale is constant and the temperature changes form 25°C to 120°C, with the increasing of the temperature, the triaxial compression strength, shear strength gradually increase, while average elastic modulus, Poisson's ratio has a slightly decrease. The thermal stress generated by the high temperature plays a role to accommodate the deformation and the function of preventing crack propagation, thus the bearing capacity of shale samples are strengthened. But the influence of temperature on shale mechanical properties mutates when the temperature is at 80°C. Shale peak strength dramatically decreased, average elastic modulus decreased slightly, and Poisson's ratio also increased slightly, which indicated that at 80°C, different thermal expansivity of mineral particles of shale may cause cross-grain boundary thermal expansion incongruous, creating additional thermal stress, thus the sample’s bearing capacity decreased.

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.

scholarly journals Experimental Study on the Influence of Moisture Content on the Mechanical Properties of Coal

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Mingxing Gao ◽  
Yongli Liu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Moisture Content ◽  
Uniaxial Compressive Strength ◽  
Poisson’S Ratio ◽  
Triaxial Compression ◽  
Test System ◽  
Poisson's Ratio ◽  
Compression Tests

Water injection in coal seams will lead to the increase of moisture content in coal, which plays an essential role in the physical and mechanical properties of coal. In order to study the influence of moisture content on the mechanical properties of soft media, the forming pressure (20 MPa) and particle size ratio (0-1 mm (50%), 1-2 mm (25%), and 2-3 mm (25%)) during briquette preparation were firstly determined in this paper. Briquettes with different moisture contents (3%, 6%, 9%, 12%, and 15%) were prepared by using self-developed briquettes. Uniaxial and triaxial compression tests were carried out using the RMT-150C rock mechanics test system. The results show that the uniaxial compressive strength and elastic modulus of briquette samples increase first and then decrease with the increase of briquette water, while Poisson’s ratio decreases first and then increases with the increase of briquette water. When the moisture content is around 9%, the maximum uniaxial compressive strength is 0.866 MPa, the maximum elastic modulus is 1.385 GPa, and Poisson’s ratio is at the minimum of 0.259. The compressive strength of briquettes increases with the increase of confining pressure. With the increase of moisture content, the cohesion and internal friction angle of briquettes first increased and then decreased.

scholarly journals An Experimental Study on the Mechanical Properties of High-Temperature Granite under Natural Cooling and Water Cooling

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Yanan Gao ◽  
Yunlong Wang ◽  
Taiping Lu ◽  
Liuzhou Li ◽  
Jinwen Wu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
High Temperature ◽  
Poisson’S Ratio ◽  
Heating Temperature ◽  
Axial Strain ◽  
Peak Stress ◽  
Poisson's Ratio ◽  
Water Cooling ◽  
Cooling Methods

With the further development of deep rock mechanics engineering, such as the exploitation and utilization of geothermal resources, the exploitation of deep mineral resources, and the safe disposal of nuclear waste, the study of mechanical properties of deep high-temperature rock is gaining the attention of the researchers. However, not only the high temperature but also the cooling condition/method that will be used in the construction such as drilling cooling will also greatly affect the mechanical properties of the rock. In this paper, the mechanical behaviour and the evolution of the mechanical properties of the high-temperature (600°C–1,000°C) granite under different cooling methods are studied. The following conclusions can be obtained: (1) The peak stress of the granite decreases with the heating temperature. Compared with natural cooling, water cooling has a more significant effect on strength degradation. (2) The increase of the heating temperature increases the maximum axial strain of the granite. The water cooling method more greatly induces the maximum axial strain of granite than the natural cooling. The maximum axial strain of the specimen under the water cooling reaches 117.3% of that under natural cooling (800°C). (3) The elastic modulus of the granite decreases with the heating temperature. Water cooling will have a stronger effect on the reduction of the elastic modulus than natural cooling. The maximum difference value (2.02 GPa) of the elastic modulus under the different cooling methods occurs at the temperature of 800°C. (4) Poisson’s ratio of the granite increases with heating temperature, and the cooling method does not have an evident effect on it. The relationship between Poisson’s ratio and the heating temperature under different cooling methods can be described using the linear model. (5) According to the influence of the temperature on the peak stress, the elastic modulus, and Poisson’s ratio, the heating temperature domain can be divided into the unapparent zone, the significant zone, and the mitigation zone. (6) The thermal stress due to the nonuniform temperature field and the different thermal expansion coefficients is incompatible. Such incompatibility stresses the essences of the degradation of the mechanical properties of the granite.

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 Investigation on the Influence of Water Content on the Mechanical Properties of Coal under Conventional Triaxial Compression

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Meichang Zhang ◽  
Rongshan Nie
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Internal Friction ◽  
Water Content ◽  
Triaxial Compression ◽  
Friction Angle ◽  
Conventional Triaxial Compression ◽  
Influence Of Water ◽  
Confining Pressures ◽  
Water Contents

The presence of water is one of the most important factors in coal mining, and it has a dual influence on the mechanical behavior of rock. To study the influence of water content on the mechanical properties of coal under complicated stress conditions, dry coal specimens and wet coal specimens with water contents of 1.8% and 3.6% were conducted by uniaxial and conventional triaxial compression tests. The relations between the uniaxial compressive strength, deformation, and water content were observed. The reductions in the strength and elastic modulus under different confining pressures were obtained. The mechanical properties of coal specimens with different water contents under triaxial compression were studied. The influences of water content on the microstructure, clay minerals, internal friction angle, and cohesive force of coal were discussed. The results show that the strengths and elastic moduli of wet specimens are clearly lower than those of dry specimens under different confining pressures. The water content has a significant influence on the postfailure mechanical behavior of coal. The loss rates of strength and elastic modulus decrease with increasing confining pressure. The water content has almost no effect on the internal friction angle, while the cohesive force of the saturated specimens is 36.5% lower than that of the dry specimens. The results can provide a reference for inhibiting the occurrence of disasters during coal mining and exploiting coal efficiently.

scholarly journals Elastic Mechanical Properties of 45S5-Based Bioactive Glass–Ceramic Scaffolds

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3244 ◽  
Author(s):  
Francesco Baino ◽  
Elisa Fiume
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Shear Modulus ◽  
Glass Ceramic ◽  
Poisson’S Ratio ◽  
Mechanical Performance ◽  
Poisson's Ratio ◽  
Shear Moduli ◽  
Bioactive Scaffolds

Porosity is recognized to play a key role in dictating the functional properties of bioactive scaffolds, especially the mechanical performance of the material. The mechanical suitability of brittle ceramic and glass scaffolds for bone tissue engineering applications is usually evaluated on the basis of the compressive strength alone, which is relatively easy to assess. This work aims to investigate the porosity dependence of the elastic properties of silicate scaffolds based on the 45S5 composition. Highly porous glass–ceramic foams were fabricated by the sponge replica method and their elastic modulus, shear modulus, and Poisson’s ratio were experimentally determined by the impulse excitation technique; furthermore, the failure strength was quantified by compressive tests. As the total fractional porosity increased from 0.52 to 0.86, the elastic and shear moduli decreased from 16.5 to 1.2 GPa and from 6.5 to 0.43 GPa, respectively; the compressive strength was also found to decrease from 3.4 to 0.58 MPa, whereas the Poisson’s ratio increased from 0.2692 to 0.3953. The porosity dependences of elastic modulus, shear modulus and compressive strength obeys power-law models, whereas the relationship between Poisson’s ratio and porosity can be described by a linear approximation. These relations can be useful to optimize the design and fabrication of porous biomaterials as well as to predict the mechanical properties of the scaffolds.

Mechanical Properties of Thin Film Silicon Carbide

2001 ◽  
Vol 687 ◽  
Author(s):  
Kamili M. Jackson ◽  
Richard L. Edwards ◽  
Guy F. Dirras ◽  
William N. Sharpe
Keyword(s):  
Mechanical Properties ◽  
Silicon Carbide ◽  
Elastic Modulus ◽  
Poisson’S Ratio ◽  
Poisson's Ratio ◽  
Massachusetts Institute Of Technology ◽  
Preliminary Results ◽  
High Temperature Electronics ◽  
Microtensile Testing ◽  
Institute Of Technology

AbstractSilicon carbide is a very attractive material for a variety of applications. Originally considered for use in high power and high temperature electronics because of its large bandgap, designers of MEMS are now considering use of silicon carbide because of its stability at high temperatures, resistance to corrosives, high stiffness, and radiation resistance. However, as with any new structural material, its mechanical properties must be measured for design information. This research measures the elastic modulus, strength, and Poisson's ratio of two different silicon carbides using microtensile testing. One material is a 0.5-1νm thick film from Case Western Reserve University. Preliminary results give an average of 420 GPa for elastic modulus, a strength of 1.2 GPa, and a Poisson's ratio of 0.19. The second material is from Massachusetts Institute of Technology with an average thickness of 30 microns. Preliminary results show an elastic modulus of 430 GPa, a strength of 0.49 GPa, and a Poisson's ratio of 0.24. In addition to the most recent results, techniques used to obtain these results, microstructure investigations, and a comparison of the materials are detailed.

scholarly journals Robust topological designs for extreme metamaterial micro-structures

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tanmoy Chatterjee ◽  
Souvik Chakraborty ◽  
Somdatta Goswami ◽  
Sondipon Adhikari ◽  
Michael I. Friswell
Keyword(s):  
Mechanical Properties ◽  
Topology Optimization ◽  
Elastic Modulus ◽  
Robust Design ◽  
Poisson’S Ratio ◽  
Mechanical Performance ◽  
Poisson's Ratio ◽  
Mechanical Metamaterials ◽  
Homogenization Approach ◽  
Micro Structures

AbstractWe demonstrate that the consideration of material uncertainty can dramatically impact the optimal topological micro-structural configuration of mechanical metamaterials. The robust optimization problem is formulated in such a way that it facilitates the emergence of extreme mechanical properties of metamaterials. The algorithm is based on the bi-directional evolutionary topology optimization and energy-based homogenization approach. To simulate additive manufacturing uncertainty, combinations of spatial variation of the elastic modulus and/or, parametric variation of the Poisson’s ratio at the unit cell level are considered. Computationally parallel Monte Carlo simulations are performed to quantify the effect of input material uncertainty to the mechanical properties of interest. Results are shown for four configurations of extreme mechanical properties: (1) maximum bulk modulus (2) maximum shear modulus (3) minimum negative Poisson’s ratio (auxetic metamaterial) and (4) maximum equivalent elastic modulus. The study illustrates the importance of considering uncertainty for topology optimization of metamaterials with extreme mechanical performance. The results reveal that robust design leads to improvement in terms of (1) optimal mean performance (2) least sensitive design, and (3) elastic properties of the metamaterials compared to the corresponding deterministic design. Many interesting topological patterns have been obtained for guiding the extreme material robust design.

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