Analysis of Static Temperature Field of Vehicle's Solid Rubber Tire

Aim To analyse the static temperature field ofthe solid rubber tire(SRT).Methods The mechanical and thermal FE models were developed and analyzed respectively with the FE software ANSYS.Results The maximum temperature becomes higher with the higher with the higher velocity of tire and scales down slightly with the higher convection coefficients.The mixed models are reasonable.Conclusion The study on static temperature field is important and reasonable.It gives the fundament for life analysis of SRT.

Temperature Dependency of Water Vapor Permeability of Shape Memory Polyurethane

Solution-cast films of shape memory polyurethane have been investigated.Differential scanning calorimetry, DMA, tensile test, water vapor permeability and the shape memory effect were carried out to characterize these polyurethane membranes. Samples cast at higher temperatures contained more hard segment in the crystalline state than a sample cast at lower temperature. The change in the water vapor permeability (WVP) of SMPU films with respect to the temperature follows an S-shaped curve, and increases abruptly at T m of the soft segment for the fractional free volume (FFV, the ratio of free volume and specific volume in polymers) increased linearly with temperature. The water vapor permeability dependency of the temperature and humidity contribute to the result of the change of diffusion and solubility with the surrounding air condition. The diffusion coefficient (D) are the function of temperature and show good fit the Arrhenius form but show different parameter values when above and below T g. The crystalline state hard-segment is necessary for the good shape memory

Electrical treeing behaviors in silicone rubber under an impulse voltage considering high temperature

In this paper,work was conducted to reveal electrical tree behaviors（initiation and propagation）of silicone rubber（SIR） under an impulse voltage with high temperature.Impulse frequencies ranging from 10 Hz to 1 k Hz were applied and the temperature was controlled between 30 °C and 90 °C.Experimental results show that tree initiation voltage decreases with increasing pulse frequency,and the descending amplitude is different in different frequency bands.As the pulse frequency increases,more frequent partial discharges occur in the channel,increasing the tree growth rate and the final shape intensity.As for temperature,the initiation voltage decreases and the tree shape becomes denser as the temperature gets higher.Based on differential scanning calorimetry results,we believe that partial segment relaxation of SIR at high temperature leads to a decrease in the initiation voltage.However,the tree growth rate decreases with increasing temperature.Carbonization deposition in the channel under high temperature was observed under microscope and proven by Raman analysis.Different tree growth models considering tree channel characteristics are proposed.It is believed that increasing the conductivity in the tree channel restrains the partial discharge,holding back the tree growth at high temperature.

Influence of Blending Temperature on Fluorescence Properties of Silicone Rubber Matrix Eu(TTA)_2(phen)(MA) Composites

A series of fluorescent composites were prepared by blending silicone rubber with Eu(TTA )2(phen)(MA). The influence of mechanical blending temperature on fluorescent intensity of composites and dispersion of rare earth complexes in the SiR matrix were investigated. As for the cured rubber, it is found that its fluorescent intensity is relatively low compared with that of uncured rubber. Low temperature is beneficial to dispersion of Eu(TTA )2(phen)(MA) homogeneously. When the amount of rare earth complexes is low, the fluorescent intensity of composites prepared by mechanical blending method above melting point of Eu(TTA )2(phen)(MA) is much higher than that of composites prepared below melting point.

Anisotropic Rock Poroelasticity Evolution in Ultra-low Permeability Sandstones under Pore Pressure,Confining Pressure,and Temperature:Experiments with Biot's Coefficient

This study aimed to show anisotropic poroelasticity evolution in ultra-low permeability reservoirs under pore pressure,confining pressure,and temperature.Several groups of experiments examining Biot's coefficient under different conditions were carried out.Results showed that Biot's coefficient decreased with increased pore pressure,and the variation trend is linear,but the decreasing rate is variable between materials.Biot's coefficient increased with increased confining pressure;the variation trend is linear,but the increasing rate varies by material as well.Generally,Biot's coefficient remains stable with increased temperature.Lithology,clay mineral content,particle arrangement,and pore arrangement showed impacts on Biot's coefficient.For strong hydrophilic clay minerals,expansion in water could result in a strong surface adsorption reaction,which could result in an increased fluid bulk modulus and higher Biot's coefficient.For skeleton minerals with strong lipophilicity,such as quartz and feldspar,increased oil saturation will also result in an adsorption reaction,leading to increased fluid bulk modulus and a higher Biot's coefficient.The study's conclusions provide evidence of poroelasticity evolution of ultra-low permeability and help the enhancing oil recovery(EOR)process.

Road Performance,Thermal Conductivity,and Temperature Distribution of Steel Slag Rubber Asphalt Surface Layer

The use of steel slag,which is a by-product of the steel manufacture,in the construction of asphalt pavement would contribute to waste reduction and environment protection.Using rubber asphalt at the same time can improve the performance of asphalt mixture.This study investigates the influence of steel slag content on the road performance,thermal conductivity and outdoor temperature distribution of steel slag rubber asphalt mixtures(SSRAM),and calculates the cumulative stress in surface layer.At a certain range of concentration,the steel slag additive improved the deformation resistance and low-temperature cracking resistance of the mixtures.The SSRAM with 40%steel slag content has the best deformation resistance while SSRAM with 60%steel slag content performed well in low-temperature cracking resistance.The thermal conductivity of the SSRAM with different steel slag content(0%,20%,40%,60%,80%,and 100%)was 1.994,2.188,2.239,2.255,2.288,and 2.295 W/(m·K),respectively.Measurements of the outdoor temperature distribution further confirmed that steel slag increased the thermal conductivity of the mixtures,thereby increasing the cumulative temperature difference between the top and bottom layers.The temperature stress and temperature-stress ratio of the SSRAM with 40%steel slag were 0.43 MPa and 0.24,while the SSRAM with 100%steel slag were 0.58 MPa and 0.36.The stress and stress ratio were much higher in the SSRAM with 100%steel slag than in the specimen with 40%steel slag.Accordingly,the maximum accumulated temperature stress aggrandized and caused early temperature cracks in the surface layer.The optimum content of steel slag was 40%.

Effect of UV radiation aging on creepage discharge characteristics of high temperature vulcanized silicon rubber at high altitude

The physicochemical properties and creepage discharge characteristics of aged high temperature Vulca nized(HTV)silicone rubber materials were investigated by ultraviolet radiati on(UV)aging method in this study.The experimental results show that as the aging time increases,the creepage discharge flashover voltage increases first and then decreases.But the aging time has little effect on the creepage discharge inception voltage.With the aging time prolonged,the discharge endurance time of HTV silicone rubber is shortened,and the creepage discharge development velocity is accelerated.In the short time of applying voltage to aging material,the magnitude of discharge in creases rapidly.According to the partial discharge characteristic parameters of creepage discharge,the whole creepage discharge process is partitioned into four stages.Compared with unaged HTV silicone rubber,the aged HTV silicone rubber has less fluctuation in performance parameters and a clear trend.The study found that UV aging not only affects the physicochemical and hydrophobic properties of the HTV silicone rubber,but also accelerates the development of creepage discharge under AC voltage.

Porosity, permeability and rock mechanics of Lower Silurian Longmaxi Formation deep shale under temperature-pressure coupling in the Sichuan Basin, SW China

To investigate the porosity, permeability and rock mechanics of deep shale under temperature-pressure coupling, we selected the core samples of deep shale from the Lower Silurian Longmaxi Formation in the Weirong and Yongchuan areas of the Sichuan Basin for porosity and permeability experiments and a triaxial compression and sound wave integration experiment at the maximum temperature and pressure of 120 ℃ and 70 MPa. The results show that the microscopic porosity and permeability change and the macroscopic rock deformation are mutually constrained, both showing the trend of steep and then gentle variation. At the maximum temperature and pressure, the porosity reduces by 34%–71%, and the permeability decreases by 85%–97%. With the rising temperature and pressure, deep shale undergoes plastic deformation in which organic pores and clay mineral pores are compressed and microfractures are closed, and elastic deformation in which brittle mineral pores and rock skeleton particles are compacted. Compared with previous experiments under high confining pressure and normal temperature,the experiment under high temperature and high pressure coupling reveals the effect of high temperature on stress sensitivity of porosity and permeability. High temperature can increase the plasticity of the rock, intensify the compression of pores due to high confining pressure, and induce thermal stress between the rock skeleton particles, allowing the reopening of shale bedding or the creation of new fractures along weak planes such as bedding, which inhibits the decrease of permeability with the increase of temperature and confining pressure. Compared with the triaxial mechanical experiment at normal temperature, the triaxial compression experiment at high temperature and high pressure demonstrates that the compressive strength and peak strain of deep shale increase significantly due to the coupling of temperature and pressure. The compressive strength is up to 435 MPa and the peak strain exceeds 2%, indicating that high temperature is not conducive to fracture initiation and expansion by increasing rock plasticity. Lithofacies and mineral composition have great impacts on the porosity, permeability and rock mechanics of deep shale. Shales with different lithologies are different in the difficulty and extent of brittle failure. The stress-strain characteristics of rocks under actual geological conditions are key support to the optimization of reservoir stimulation program.

Study of Temperature Effect on the Coal Seam Permeability

In order to obtain the law of temperature’s effect on coal permeability,the simulation system of independently developed coalbed gas dynamics actions was used as the experimental platform.First,coal sample was put in the vessel and at the same time rock stress sensors and gas pressure sensors were put in the coal sample in sequence.Second,the coal sample was compacted under high pressure,and the physical experimental model

High Temperature Gas Permeability Tester for Refractories and Its Application

In this paper,an ideal structural model and a scientific and practical mathematical model of high temperature permeability testing technology were established based on the formula of gas permeability at room temperature according to Darcy’s equation and Forchheimer equation and combined with the basic law of gas mechanics and the resistance loss of gas movement process at high temperatures.Through a gas heater,the safe heating of gas from room temperature to the test temperature was realized;the pressure sealing of high temperature permeability test technology was studied using high temperature resistant flexible material instead of silica gel material and combining preloading with system expansion and continuous loading.Based on the above research,a high temperature gas permeability tester for refractories has been developed and the test temperature can be up to 1000℃.The equipment was applied to research refractories,showing well using effects.

Hydrophilicity Modification of Addition-cured Room Temperature Vulcanization Silicone Rubber

Allyl terminated polyether was used to improve the hydrophilicity of addition-cured room temperature vulcanization silicone rubber. With the increasing of the polyether, both the hydrophilicity and water absorbed of the vulcanizates were increased. The mechanical properties were also improved by adding the polyether. The result showed that 1.5wt% of the polyether provided the silicone rubber with proper hydrophilicity.

Optimization of technical measures for improving high-temperature performance of asphalt-rubber mixture

Asphalt-rubber pavements often become dam-aged in high-temperature regions and appear rutted or wavy, and experience slippage. To improve the high-temperature performance of the asphalt-rubber mixture, technical measurements, such as, the optimal adjustment of gradation, technique of composite modification, and control of compaction were investigated. An optimal adjustment of aggregate gradation based on stone matrix asphalt improves the high-temperature stability of the asphaltrubber mixture significantly. Through composite modifi- cation, the effect of asphalt-rubber modification was enhanced, and the dynamic stability and relative defor- mation indices of the asphalt-rubber mixture were improved significantly. Furthermore, compaction parame- ters had a significant influence on the high-temperature stability of the asphalt-rubber mixture. The rolling times for compacting the asphalt-rubber mixture should be controlled to within 18-20 round-trips at a molding temperature at 180℃; if the rolling time is a 12 round-trip, the compaction temperature of the asphalt-rubber mixture should be controlled between 180 and 190℃.

Temperature field analysis of two rotating and squeezing steel-rubber rollers

Rubber has strong nonlinear viscoelastic characteristic. Under effect of the periodically changing external force,it will show the phenomenon of lagging deformation and mechanical loss,which means deformation lags behind stress changes and the situation of loss of work is caused by the hysteresis. Loss of work will be transformed into thermal energy and makes the temperature of rubber and the object in contact with it rise,which will thereby affect the dynamic characteristics of the structure. Based on a pair of mutual rotating and squeezing steel-rubber rollers as the research object,the finite element simulation software Ansys is used in this paper to analyze the temperature field of the structure. As a result,temperature distribution characteristics of two directions are obtained. One is squeezing area along the direction of the wall,the other is along the direction of thickness of rubber. Then the influence of the rotating speed and the pressure between two rollers on temperature of rubber is analyzed. The temperature experiment of mutual squeezing contact steelrubber roller is carried out on the experimental platform via using infrared thermal imager and infrared thermometer. The experiment data are in accordance with the simulation results on regulation of temperature distribution as well as high degree of similarity on value,which shows the effectiveness of simulation. Research results are of great significance for temperature characteristic analysis of rubber structure.

The mechanism of inward and outward expansion of multiscale dynamic permeability of coalbed methane at different temperatures

The multiscale micro-nano pores in coal can result in the ultra-low permeability of coal,which restricts the efficiency of gas extraction.It is difficult for the conventional seepage-enhancement measures to affect the nanoscale pores within the coal matrix.Thermal stimulation can reach deep into the micro-nano pores within coal matrix to improve the permeability.Therefore,it is important to study the diffusivity and permeability of the multiscale micro-nano pores at different temperatures.In this study,the experiments of diffusion-seepage measured by the methods of GRI(Gas Research Institution)and steady-state were conducted using a cylindrical coal at different temperatures and pressures.The experimental results show that the apparent diffusion coefficient of cylindrical coal is not constant but variable dynamically;and the classical diffusion model fails to describe the full-time process of gas flow accurately.On this basis,a model of multiscale dynamic apparent diffusion-seepage that can accurately describe the full-time flow process was proposed.As is observed,the apparent permeability attenuates dynamically with time without stress loading,and the initial apparent permeability and the attenuation coefficient increase monotonically with the rise of temperature.Under the stress constraint,the steady-state permeability increases after a decrease as the temperature rises,displaying a“U-shaped”pattern.Without stress constraint,the increasing temperature causes the exterior multiscale pores to expand outward by different degrees so as to increase permeability,while the interior micro-nano pores show three inward and outward expansion mechanisms.Under stress constraint,at low temperature and high effective stress,the increasing temperature causes pores to expand inward and the permeability decreases accordingly.When temperature continues to increase,coal expands outward because the effective stress is counteracted by the thermal stress,leading to an increase in permeability.This study is of significance for thermal gas extraction engineering.

Effects of effective stress and temperature on permeability of sandstone from CO2-plume geothermal reservoir

Rock is generally complex and heterogeneous,therefore the heterogeneity effects of effective stress and temperature on permeability should be taken into account.In this study,two-part Hooke’s model（TPHM） is introduced to understand the influences of effective stress and temperature on permeability of soft and hard parts（two parts） of rock based on coupling thermo-hydro-mechanical tests.Under a fixed temperature level（25 ℃.35 ℃.50 ℃.65 ℃.80 ℃.90 ℃ and 95 ℃）.the tests were carried out in a conventional triaxial system whereas the confining pressure was remained at 50 MPa.and the pore pressure was increased to the specified levels step by step.i.e.8 MPa,18 MPa.28 MPa.38 MPa.41 MPa,44 MPa.46 MPa and 48 MPa.The temperature-dependent relationships for two parts permeabilities are proposed on the basis of the initial test results.We point out that temperature of 65 ℃-90 ℃ is the threshold for the development of CO2-plume geothermal（CPC） reservoir sandstone cracking under low effective stress（2-9 MPa） based on the relationship between temperature and soft part permeability.Furthermore,we discuss the effect of temperature on the two parts in the rock.The results indicate that as the temperature increases from 25 ℃ to 65 ℃.the flow channel in the hard part has a stronger response to temperature than that in the soft part at a fixed effective stress level,which is opposite to the situation of effective stress.Considering that natural rock is generally heterogeneous with non-uniform pore structure,we suggest a physical interpretation of the phenomenon that before the thermal cracking threshold the two parts have different responses to temperature.

Hand Cooling Enhances the Proprioceptive Drift during Rubber Hand Illusion

Background: The neural representation of the body is easily altered by integrating multiple sensory signals in the brain. The “Rubber Hand Illusion” (RHI) is one of the most popular experimental paradigms to investigate this phenomenon. During this illusion, ownership of a rubber hand is temporarily induced. It was shown that external and continuous cooling of the palm enhanced the RHI, suggesting an association between altered the autonomic nervous system regulation and altered the sense of ownership of a specific limb. Purpose: To investigate whether artificially cooling the entire hand for a short period affects the magnitude of the illusion. Methods: Participants immersed their entire hand in cool, cold, or warm water for 1 min before the RHI procedure. Results: We found that cooling the entire hand enhanced the proprioceptive drift during the RHI but not the subjective feeling of ownership. In contrast, warming and intense cooling of the entire hand did not affect the RHI strength. Conclusion: Our results suggest that transient and moderate cooling of the entire hand was sufficient in enhancing the illusory disembodiment of one’s own hand.

Numerical modelling rock deformation subject to nitrogen cooling to study permeability evolution

How to model the permeability evolution of rock subjected to liquid nitrogen cooling is a key issue. This paper proposes a simple but practical method to study the permeability evolution of rocks subject to liquid nitrogen cooling. FLAC with FISH function was employed to numerically model the rock behavior under cooling. The enhanced perme- ability of the volumetric strain was defined, and the permeability was directly evaluated based on element＇s volumetric strain. Detailed procedures for implementing the evolution model of permeability in this paper were presented. A case study was carried out to simulate a coal bed where liquid nitrogen was injected in the bore hole. And a semi-submerged test of liquid nitrogen was performed. The method to model the permeability evolution of rocks subject to liquid nitrogen shock in this paper was proved to be right by the test results. This simulation results are discussed with the hope to provide some insight into understanding the nitrogen cooling practice.

Experimental study on the influence of temperature cycle on low-rank coal permeability

The formation temperature is a key factor affecting coalbed methane(CBM)migration in reservoirs.Both the prediction of CBM production and prevention of mine gas disasters require the understanding on the controlling mechanism of temperature on coal permeability.We experimentally examined the evolution of permeability for natural low-rank coal samples under various stresses and cyclic temperature conditions.Apparent permeability and intrinsic permeability decrease significantly when the temperature increases and they only partially recover after the temperature returns.The permeability loss decreases greatly with the increasing number of temperature cycles.The permeability loss due to the rising temperature and the irreversible permeability loss for a whole temperature cycle decrease prominently with increasing confining stress.The impacts of swelling/shrinking of coal matrix,roughness of surface,pore compressibility and weakly bound water in coal on temperature sensitivity of coal permeability are investigated.

Experimental investigation into temperature effect on hydro-mechanical behaviours of bentonite

The bentonite barrier of underground repositories for high-level radioactive waste will be hydrated by the groundwater while it is subjected to high temperatures due to the radioactive decay of the wastes. These changes of temperature affect the hydraulic and mechanical responses of bentonite, which has important effects on design and performance of repositories. The temperature influence on the hydro-mechanical behaviour of bentonite was studied in this paper by experiments, which were carried out with the Spanish FEBEX bentonite compacted at dry densities expected in the＇ repository （from 1.5 to 1.8 Mg/m^3）. The dependence of the swelling strains of bentonite on the temperature has been measured from 30℃ to 90 ℃. At high temperatures the swelling capacity of clay slightly decreases. Also, a clear decrease of swelling pressure as a function of temperature was observed for the same dry densities. Nevertheless, the deformation of bentonite is more dependent on the stress than the temperature. An increase in the permeability of water saturated bentonite with temperature has also been detected. The water retention curves of bentonite compacted at different dry densities were determined under isochoric conditions and in the range of temperatures from 20 ℃ to 120℃. For a given density and water content, the suction decreases as the temperature increases at a rate, which is larger than the one predicted on the basis of water surface tension changing with temperature. Mechanisms related to the physico-chemical interactions that take place at microscopic level, in particular the transfer of interlayer water to the macropores triggered by temperature, seem to explain qualitatively the experimental observations.