The Effect of Temperature on Tensile and Compressive Strengths and Young's Modulus of Oil Shale

Six different sandstone units were studied to investigate and quantify the relationship between their mechanical properties (compressive strength, tensile strength, Young's modulus, Poisson's ratio), petrographic characteristics, and engineering index properties. Sandstones investigated included the Sharon sandstone, the Juniata sandstone, the Morgantown-Grafton sandstone, and three Berea sandstone units. These sandstones were tested for percent absorption, density, slake durability, total pore volume, uniaxial compressive strength, tensile strength, Young's modulus, and Poisson's ratio. Petrographic characteristics studied included grain size, grain shape, grain sorting, packing density, packing proximity, degree of grain interlocking, and mineral composition. The data were analyzed statistically to determine the quantitative relationships between various properties. Results indicate that compressive strength, tensile strength, and Young's modulus values for the sandstones studied are closely related (r>0.7) to their density, percent absorption, total pore volume, and type of grain-to-grain contacts. Generally, sandstones with higher densities, lower percent absorption, lower total pore volume, and higher percentage of sutured contacts exhibited higher values of compressive strength, tensile strength, and Young's modulus. For Poisson's ratio, however, inverse relationships were observed with compressive strength and Young's modulus. Based on these results, equations were developed for predicting mechanical properties from values of density, percent absorption, total pore volume, and percent sutured contacts.

The initial temperature has a considerable effect on aluminum polycrystals' physical stability and mechanical performance, with the possibility to optimize their mechanical properties for practical applications. Thus, using a molecular dynamics technique, the effect of temperature on the mechanical properties of aluminum polycrystals is studied. Stress-strain curves, ultimate strength, and Young's modulus were all measured at temperatures of 300, 350, 400, and 450 K. The findings from MD simulations show that the initial temperature significantly affects the physical stability and mechanical performance of designed aluminum polycrystals. The aluminum polycrystal experiences a numerical increase in ultimate strength and Young's modulus from 6640 to 74.072 to 7.055 and 79.226 GPa, respectively, when subjected to the optimal initial conditions of 350 K. With further increasing temperature to 450 K, ultimate strength and Young's modulus decrease to 6.461 and 74.413 GPa, respectively. The observed decrease in ultimate strength and Young's modulus of the aluminum polycrystal as the temperature increased from the optimal condition of 350 K–450 K can be attributed to the weakening of interatomic attraction forces at higher temperatures. This reduction in interatomic bonding strength resulted in decreased material stiffness and resistance to deformation, leading to lower ultimate strength and Young's modulus values. This study's novelty lies in its comprehensive assessment of the initial temperature's effects on the mechanical performance of aluminum polycrystals, providing valuable insights for practical applications and advancing beyond previous efforts in the literature.

The effect of compressive prestressing on the mechanical properties of some nuclear graphites

Although many shale oil wells have been drilled recently in the Eagle Ford shale oil field, wellbore stability problems in the shale oil reservoirs have not been fully understood. During drilling, fracturing, and production operations, the wellbore temperature is not constant but varies during these operations. This temperature fluctuation results in thermal cycling which tends to alter rock physical properties such as compressive strength, Young's modulus (E), and Poisson's ratio (ν), and consequently, result in wellbore stability problems. Wellbore stability problems are one of the most costly problems that can occur during drilling operations, especially in unconventional reservoirs. These problems include but are not limited to tight holes, pipe sticking, fishing, sidetracking, and well abandonment. Since the majority of wells are drilled horizontally in shale oil reservoirs, the likelihood of wellbore stability problems is dramatically increased. Thus, to have more efficient and effective drilling operations through these formations, a better understanding of their properties as well as the effects of drilling conditions on rock properties such as compressive strength, Young's modulus (E), and Poisson's ratio (ν) are required. Not many experiments have been performed to investigate the effect of temperature on sedimentary rocks' properties such as compressive strength. Some experiments have been conducted to assess the effect of temperature on shale rock samples, since shale oil rock samples are quite different from common shale rock samples, the results cannot be equally applied to shale oil and shale gas formations. For this study, the mineralogy of shale oil core samples from the Eagle Ford field was determined. To simulate actual well conditions a High Pressure High Temperature (HPHT) setup was built and used which let us apply different axial and radial confining stresses, equivalent formation pore pressure, and drilling fluid wellbore pressure. The experiments were conducted under elevated temperatures to better mimic real drilling operations. Saturated shale oil core samples from the Eagle Ford field were tested under various temperatures including reservoir temperature. We also performed Unconfined Compressive Strength (UCS) tests to investigate the effect of temperature on the compressive strength of the core samples. The experimental setup was modified to accommodate five Linearly Variable Displacement Transducers (LVDTs) to measure Young's Modulus (E) and Poisson's ratio (ν). Various experiments were run to quantify the effect of temperature on the rock compressive strength, E, and ν. Experiments have shown a distinct change in the mechanical properties of the rock. These effects will be discussed in details.

In this study, the relationships between porosity and Young's moduli measured by an acoustic pulse method, a resonance frequency technique, a tensile test and a bending test of sintered irons were investigated. Moreover, tensile strength and proof stress were measured by tensile test, and these values and Young's modulus were evaluated against porosity.Young's moduli measured by the acoustic pulse method, resonance frequency technique and tensile test, except for the bending test, were nearly equal at the same porosity. In the case of the bending test, the moment of inertia of the area was a linear function of porosity. Young's modulus measured by the bending test, which was corrected by use of the above relation, was equal to that by other method. Young's modulus measured by the bending test was 0.7-0.8 times of Young's modulus measured by the tensile test.Young's modulus (E), tensile strength (Ts) and proof stress (Ps) against porosity (P) are expressed as E=(E0-KE⋅P) (1-P), Ts=(Tso-KTs⋅P)(1-P) and Ps=(Pso-Kps⋅P)(1-P), respectively. Here, E0, Tso and Pso are Young's modulus, tensile strength and proof stress at P=0, and KE, KTS and KPS are the experimental coefficients of each relation. Moreover, we found that the relationships among Young's modulus, tensile strength and proof stress are in positive correlation.

What controls the mechanical properties of shale rocks? – Part I: Strength and Young's modulus

A Study of the Physical and Mechanical Properties of Wheat Straw

The foremost function of primary cementing is to achieve zonal isolation and ensure long-term cement integrity during the lifetime of the well. Current advanced drilling and cementing technologies enable the production of oil and gas in more complex and challenging conditions such as deep wells and unconventional wells either onshore or offshore. Understanding the mechanical performance of cement sheath under downhole conditions, therefore, is crucial for successful cementing operations. Unfortunately, most published mechanical data were still limited to the compressive and tensile strengths determined at ambient condition as well as Young's modulus. The result for tensile strength varies greatly due to the lack of API standard tensile strength testing. The purpose of this study is to evaluate the additive-additive interaction on cement mechanical properties. Individual additives and their combinations were mixed with class H cement at a density of 16 ppg and cured under elevated temperature and pressure. The mechanical properties tested at ambient and curing conditions include compressive, tensile and yield strength, Young's modulus, and Poisson's ratio. The cement mechanical performances measured at curing conditions, especially the tensile strength, were different from the results obtained at ambient conditions. The elasticity of cement was improved by fiber and polymeric additives tested in this work. This study provides comprehensive experimental data on how the slurry formulation, chemical characteristics of the additives, and additive-additive interactions can affect cement mechanical properties. This study also gives insights into the correlations among various mechanical properties, and the key parameters that could determine cement elasticity. The results can be used as direct guidance for future field applications.

MP66-11 COMPARISON OF THE BIO-MECHANICAL PROPERTIES OF HUMAN AND BABOON’s TUNICA ALBUGINEA

Mechanical properties of strain annealed metal amorphous nanocomposite (MANC) soft magnetic material

Recently, the effect of temperature on the mechanical property (the Young's modulus) of the single-layer molybdenum disulfide (SLMoS2) is shown to be insignificant, which is obviously incompatible with the previously published result, i. e. the Young's modulus of SLMOS2 decreases monotonically as temperature increases. Aiming at clarifying the relationships between the mechanical properties of the single-layer molybdenum disulfide (SLMoS2) along the armchair (AC) and zigzag (ZZ) directions and the temperature, classical molecular dynamics (MD) simulations are performed to stretch the SLMoS2 along the AC and ZZ directions at the temperatures ranging from 1 K to 800 K by using the Stillinger-Weber (SW) interatomic potentials in this paper. The mechanical properties of SLMoS2 at the temperatures ranging from 1 K to 800 K, including ultimate strength, ultimate strain, and Young's Modulus, are calculated based on the stress-strain results obtained from the simulations. Results are obtained and given as follows. (1) The mechanical properties of the SLMoS2, including the ultimate strength and Young's modulus, are found to monotonically decrease as temperature increases. Increasing the temperature, the ultimate strength of SLMoS2 in the AC direction drops faster than in the ZZ direction, whereas the Young's modulus of SLMoS2 in the ZZ direction decreases quicker than in the AC direction, which means that the chirality effect on the ultimate strength is remarkably different from the Young's modulus of SLMoS2. However, the ultimate strain in the ZZ direction at the temperatures in a range from 1 K to 800 K is close to that in the AC direction, which means that the effect of chirality on the ultimate strain is insignificant. (2) Unlike the published results in the literature, the phase transition of SLMoS2 is found to only occur at a temperature of 1 K and at the moment of initial crack formation as tensiled along the ZZ direction, and the new phase of quadrilateral structure keeps stable after unloading. (3) The linear thermal expansion coefficients along the ZZ and AC directions are also measured, the magnitudes of which are found to be consistent with the published experimental results. Our simulation results support the viewpoint that the effect of the temperature on the mechanical property of SLMoS2 is significant, and the SLMoS2 can be regarded as an anisotropic material as the chirality effect cannot be ignored. The linear thermal expansion coefficients obtained with MD simulation are all in good agreement with the experimental data.

Mechanical compatibility of titanium implants in hard tissues

Tensile properties of soft contact lens materials

The Young's modulus of concrete should be at least 0.8 times of the value calculated by the equation in JASS 5 (AIJ calculated value). Whereas one of the major factors affecting the Young's modulus of concrete is the Young's modulus of coarse aggregate, the information on the Young's modulus of coarse aggregate that satisfies the target value of JASS 5 is not shown clearly. Furthermore, whereas it is necessary to confirm the Young's modulus of concrete of the mixture proportion which is more dangerous than the actual mixture proportion prior to the construction, the definition of "more dangerous mixture proportion" is not shown clearly. In this study, based on the results of experiments for high strength concretes using crushed stones with the maximum size 20 mm, the influences of the Young's modulus and volume of coarse aggregate on the Young's modulus of concrete were investigated. An ordinary portland cement and a cement for high strength concrete containing silica fume were used as cements. Mainly, an andesite crushed sand was used as fine aggregate. Three kinds (andesite, hard sandstone, limestone) of crushed stones were used as coarse aggregates. Using specimens (φ50×100 mm) taken from ores, the compressive strength and the Young's modulus of coarse aggregates were measured. Range of water-cement ratio of concrete was 0.15-0.40. Range of absolute volume of coarse aggregate per unit volume of concrete was 0.09-0.36 m3/m3. Additionally, the mortars of mixture proportions which are removed coarse aggregates from concretes were produced. Preparing standard cured specimens (φ100×200 mm) of concretes and mortars, the compressive strength and the Young's modulus of them were measured at the ages of 7, 28 and 91 days. It was confirmed that the Young's modulus of high strength concrete is possible to be estimated based on the Young's modulus and the component ratio of each phase (mortar and coarse aggregate). However, in the case which the Young's modulus of concrete was small, the measured value tended to be slightly smaller than the estimated value by Hashin-Hansen equation3). Thus, by combining the equations for estimating the Young's modulus of mortar and concrete and for estimating the compressive strength of concrete6),9), the evaluation method of the relationship between the compressive strength and the Young's modulus of concrete based on the Young's modulus of coarse aggregate was proposed. The Young's modulus of coarse aggregate was evaluated to be between 5.5-7.0×104 MPa by this proposed method when the Young's modulus of concrete was about the same value as AIJ calculated value. On the other hand, the Young's modulus of coarse aggregate was evaluated to be about 4.0×104 MPa by this proposed method when the Young's modulus of concrete was about 0.8 times of AIJ calculated value. Based on this results, the reference value of the Young's modulus lower limit of coarse aggregate was shown as 4.0×104 MPa in order to meet the target value of the Young's modulus of concrete in JASS 5.

The Institute for Standards Research interlaboratory study of rock properties has provided precision statements for two additional ASTM rock-property test methods, D 5407 (Young's modulus and Poisson's ratio) and D 2664 (ultimate strength), both in confined compression. Three types of intact rock, Barre Granite, Berea Sandstone, and Tennessee Marble, were used in this study. Data were collected for both test methods at confining pressures of 10, 25, and 40 MPa, with four replications per rock type. The rock testing was preceded by pilot testing for Young's modulus and Poisson's ratio on aluminum alloy 2024 T351, with three replications. Young's modulus and Poisson's ratio were evaluated, for both aluminum and rock, from stress-strain data for the intervals from 25–50% and 40–60% of the maximum differential stress. Seven laboratories produced pilot data, and six of these laboratories produced data on rock for this report. Both the aluminum and rock specimens were prepared at central locations and were furnished ready for testing to the participating laboratories. For both elastic moduli, the overall normalized repeatability limit (“within laboratory”) for rock is about twice that for aluminum; the overall normalized reproducibility limit (“between laboratory”) for rock is about the same as that for aluminum.