Infrared Thermal Image Study on Failure of Granite with Hole

2007 ◽  
Vol 353-358 ◽  
pp. 2313-2316 ◽  
Author(s):  
Zhi Hong Tan ◽  
Chun An Tang ◽  
Wan Cheng Zhu
Keyword(s):  
High Temperature ◽  
Thermal Effects ◽  
Rock Sample ◽  
Failure Process ◽  
Close Relation ◽  
Local Area ◽  
Thermal Image ◽  
Image Study ◽  
Granite Sample ◽  
Infrared Thermal Images

The changing behavior for infrared thermal image omen of the rock with fracture is essential for the geotechnical engineering. In order to study the behavior, the infrared thermal images for the failure process of rock with hole are carried out. The size of the rock sample is 20cm×10cm×2cm with hole at the center of the sample and the diameter of the hole is 1cm. Considering the fact that sample will effect the results of the observation for infrared thermal image during the experiment, the laminated granite sample was used to replace the cylinder or cuboid sample. The achieved results under uniaxial compression indicate that intensity of the micro ruptures have a close relation with the thermal effects. When the main fractures happen, there is a strip of high temperature that will appear at the destructed local area. During loading process, the abnormity of infrared temperature has two kinds of behaviors as follows: (1) temperature rises and falls alternately, rises before the fracture; (2) temperature falls slowly at beginning, and then rises slowly, then rises quickly before the fracture appears. Even for the same rock sample, the behaviors of the infrared phenomenon may be different during failure.

scholarly journals Particle Flow Analysis of Macroscopic and Mesoscopic Failure Process of Salt Rock under High Temperature and Triaxial Stress

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Haoran Li ◽  
Ziheng Wang ◽  
Dekang Li ◽  
Yajun Zhang
Keyword(s):  
Plastic Deformation ◽  
High Temperature ◽  
Rock Sample ◽  
Triaxial Compression ◽  
Failure Process ◽  
Particle Flow ◽  
Heating Process ◽  
Salt Rock ◽  
Fracture Development ◽  
Simulation Results

In order to reveal the mechanism of thermal-induced deformation and fracture development of salt rock under high temperature, the particle flow program PFC2D was used to study the triaxial compression failure process of salt rocks under different temperatures; at the same time, a combination model of Burge and Linearpbond was proposed to simulate plastic deformation and heat conduction of salt rock. Finally, the simulation results were compared with the experimental results to verify the validity of the conclusion. The simulation results show that the elastic limit points of rock gradually descend, the dilatancy points rise gradually, and the plastic deformation characteristics of salt rock become more obvious with the increase of temperature. Due to the damage of the sample, the strong chains break and disappear, increasing the proportion of the weak chains, and the high temperature intensifies the rupture of the contact between the particles in the salt rock. As the temperature increases from 50°C to 120°C, the strong chains in the rock sample decrease significantly, and the damage gradually increases; when the temperature is 150°C, the contact force decreases sharply, and the damage of salt rock is significant. According to the particle displacement cloud diagrams, it is found that the expansion direction from the middle part of the rock sample to the left and right ends is 12.08°, 9.55°, 8.2°, 6.33°, and 0°, respectively. The displacement directions of the rock sample show obvious radial expansion tendency, and the higher the temperature, the more obvious the “drum-shaped” failure phenomenon in the middle of the rock sample. During the heating process, the thermal cracks are mainly tensile cracks, and transverse cracks are gradually formed in the middle of the model. The cementation failure points at the top and bottom of the model expand in an oblique direction and form oblique cracks of about 45°. From the three different mathematical models of macroscopic and mesoscopic views, it is concluded that the effect of temperatures on salt rock is more significant after 90°C. This research is important for exploring the macroscopic and microscopic mechanics evolution of salt rock and provides a reference for determining the long-term mechanical strength of salt rock.

Effect of CO2 on Anti-Corrosion Property of a Polyurea Coating Modified with Organosilicone

2014 ◽  
Vol 789 ◽  
pp. 466-470
Author(s):  
Qing Hao Shi ◽  
Bing Ying Wang ◽  
Bin Zhao
Keyword(s):  
High Temperature ◽  
Partial Pressure ◽  
Composite Coating ◽  
Corrosion Test ◽  
Electrochemical Impedance ◽  
Failure Process ◽  
Corrosion Property ◽  
Corrosion Mechanism ◽  
Partial Pressures ◽  
High Temperature High Pressure

The corrosion mechanism of organic silicon modified polyurea composite coating under different CO2 partial pressures was studied using high-temperature autoclave, combined with scanning electron microscopy (SEM), adhesion tests and electrochemical impedance spectroscopy (EIS) technology. The experimental results showed that: there was no corrosion product formed on the surface of coating sample after high-temperature high-pressure corrosion test, and with the increasing of CO2 partial pressure, the coating adhesion and impedance values decline increases. Moreover CO2 partial pressure increases accelerated the failure process of polyurea composite coating system.

Thermal Effects in the Organocatalytic Asymmetric α-Amination of Disubstituted Aldehydes with Azodicarboxylates: A High-Temperature Organocatalysis

2008 ◽  
Vol 2008 (13) ◽  
pp. 2207-2212 ◽  
Author(s):  
Thomas Baumann ◽  
Michael Bächle ◽  
Caroline Hartmann ◽  
Stefan Bräse
Keyword(s):  
High Temperature ◽  
Thermal Effects

Design of High Temperature and High Pressure Petroleum Bullets Performance Test Device

2012 ◽  
Vol 580 ◽  
pp. 346-349
Author(s):  
Xiao Qing Li ◽  
Ren Qiang Liu ◽  
Da Zhong Hua ◽  
Xiao Yan Liu
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
High Temperature ◽  
Performance Test ◽  
Convection Heat Transfer ◽  
Local Area ◽  
Temperature Fields ◽  
Test Time ◽  
Test Device ◽  
High Pressure Reaction

A high temperature and high pressure reaction autoclave for petroleum bullets performance test is designed in this paper. Heat transfer in both vertical and horizontal reaction autoclave structure is analyzed and calculated. Considering system heat loss, heating power of these two kinds of devices is calculated in different test time. Meanwhile, temperature fields in these two kinds of autoclave are simulated. According to the comparison result, the authors come to the conclusion that temperature field in vertical reaction autoclave is uniform and can meet design demand with a temperature difference less than ±5°C. Horizontal reaction autoclave in which there are small eddies in air interlayer cannot meet demand because eddies enhance the convection heat transfer in local area. Based on this conclusion, a reasonable reaction autoclave structure can be designed.

High-Temperature Modifications of Thorium Dicarbide

1964 ◽  
Vol 8 ◽  
pp. 78-85 ◽  
Author(s):  
P. K. Gantzel ◽  
S. Langer ◽  
N. L. Baldwin ◽  
F. L. Kester
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
High Temperature ◽  
Thermal Effects ◽  
Room Temperature ◽  
Thermal Analyses ◽  
Tetragonal Modification ◽  
X Ray ◽  
Space Groups ◽  
Heating And Cooling

AbstractThermal analyses of samples of thorium dicarbide in equilibrium with graphite show arrests which indicate phase transitions at 1427 ± 21°C arid 1481 ± 28°C. These thermal effects have been observed on heating and cooling both in standard thermal analysis and in differential thermal analysis using graphite as a reference material. The microstructure of thorium dicarbide samples shows the characteristic “herringbone” pattern of a material which has undergone a martensitic-type transition.A high-temperature X-ray investigation has revealed that the observed thermal arrests correspond to erystallographic transformations. The monodinic modification found at room temperature is stable to 1427°C, at which temperature a tetragonal modification with a0 = 4.235 ± 0.002Å and c0 = 5.408 ± 0.002Å is formed. At 1481°C, the tetragonal is transformed to cubic with a0 = 5.809 ± 0.002 Å. The best agreement between observed and calculated intensities has been obtained with C-C units of 1.5-Å assumed bond length in space groups P42/mmc and Pa3 for the tetragonal and cubic modifications, respectively.

Model Testing and Analysis Study on Shear Strength of Rock Mass Containing Multiple Cracks under Compression-Shearing Loading

2008 ◽  
Vol 33-37 ◽  
pp. 617-622
Author(s):  
Wei Shen Zhu ◽  
Bin Sui ◽  
Wen Tao Wang ◽  
Shu Cai Li
Keyword(s):  
Shear Strength ◽  
Rock Mass ◽  
Rock Sample ◽  
Failure Process ◽  
Jointed Rock ◽  
Multiple Cracks ◽  
Test Results ◽  
Failure Model ◽  
Two Phase ◽  
Bridge Failure

Two-phase modelling testing was performed to study the shear strength of rock bridges of jointed rock mass in this paper. The failure process of rock sample containing multiple collinear cracks was observed. Based on theory of fracture mechanics and analytical method, a rock-bridge failure model was proposed and the expression of shear strength was derived. Comparison of calculated shear strength and the model test results was made and they agree well.

scholarly journals The Lyman-α forest as a diagnostic of the nature of the dark matter

2019 ◽  
Vol 489 (3) ◽  
pp. 3456-3471 ◽  
Author(s):  
Antonella Garzilli ◽  
Andrii Magalich ◽  
Tom Theuns ◽  
Carlos S Frenk ◽  
Christoph Weniger ◽  
...  
Keyword(s):  
Dark Matter ◽  
High Temperature ◽  
High Resolution ◽  
Power Spectrum ◽  
Early Universe ◽  
Thermal Effects ◽  
Cold Dark Matter ◽  
Sterile Neutrinos ◽  
Hydrodynamic Simulations ◽  
Very High

ABSTRACT The observed Lyman-α flux power spectrum (FPS) is suppressed on scales below ${\sim} ~ 30\, {\rm km\, s}^{-1}$. This cut-off could be due to the high temperature, T0, and pressure, p0, of the absorbing gas or, alternatively, it could reflect the free streaming of dark matter particles in the early universe. We perform a set of very high resolution cosmological hydrodynamic simulations in which we vary T0, p0, and the amplitude of the dark matter free streaming, and compare the FPS of mock spectra to the data. We show that the location of the dark matter free-streaming cut-off scales differently with redshift than the cut-off produced by thermal effects and is more pronounced at higher redshift. We, therefore, focus on a comparison to the observed FPS at z > 5. We demonstrate that the FPS cut-off can be fit assuming cold dark matter, but it can be equally well fit assuming that the dark matter consists of ∼7 keV sterile neutrinos in which case the cut-off is due primarily to the dark matter free streaming.

Microscopic Study on Mechanical Properties of Different Microregions during In-Service Welding

2019 ◽  
Vol 944 ◽  
pp. 841-853
Author(s):  
Ling Qiao ◽  
Tao Han ◽  
Hong Tao Wang ◽  
Lai Hui Han ◽  
Shi Wei Gu
Keyword(s):  
High Temperature ◽  
Dynamic Properties ◽  
Failure Process ◽  
Physical Nature ◽  
Repair Process ◽  
Scientific Basis ◽  
Economic Benefits ◽  
Dynamics Simulation ◽  
Microscopic Mechanism ◽  
Burn Through

In-service welding has been gaining considerable attentions due to its significant economic benefits. At high temperature, several technical difficulties exist during repair process and burn-through has been one of the critical issues. To reveal the physical nature of burn-through, finite element simulation and molecular dynamics simulation are combined to investigate the micro dynamic properties of different micro regions in welded joint and the effect of crack on the microdynamic behavior in the process of material failure. The results indicate that burn-through is a failure process under the effect of tensile stress and high temperature. The performance near fusion line is the worst and a burn-through tends to occur at the regions behind maximum melting depth. The failure process of welded joints experience the initiation and development of micro defects. Continuous expansion of micro holes and micro cracks causes the structural fracture. Furthermore, the micro crack would decrease the structural strength and the failure mode differs for cracks in different direction. Failure process of crack structure has experienced the crack tip passivation and dislocation emission. And the formation of stacking fault is carried out in failure process. This paper reveals the microscopic mechanism of burn-through at the atomic level and provides a scientific basis for the continuous and safe operation of gas pipelines.

scholarly journals EQUATION OF STATE FOR DENSE SUPERNOVA MATTER

2009 ◽  
Vol 18 (08) ◽  
pp. 1205-1226 ◽  
Author(s):  
C. C. MOUSTAKIDIS
Keyword(s):  
High Temperature ◽  
Equation Of State ◽  
Nuclear Matter ◽  
Thermal Effects ◽  
Effective Interaction ◽  
Interaction Model ◽  
Decay Process ◽  
High Density ◽  
Β Decay ◽  
Charge Neutrality

We provide an equation of state for high density supernova matter by applying a momentum-dependent effective interaction. We focus on the study of the equation of state of high density and high temperature nuclear matter containing leptons (electrons and neutrinos) under the chemical equilibrium condition. The conditions of charge neutrality and equilibrium under the β-decay process lead first to the evaluation of the lepton fractions and afterward to the evaluation of internal energy, pressure, entropy and, in total to the equation of state of hot nuclear matter for various isothermal cases. Thermal effects on the properties and equation of state of nuclear matter are evaluated and analyzed in the framework of the proposed effective interaction model. Since supernova matter is characterized by a constant entropy, we also present the thermodynamic properties for the isentropic case. Special attention is devoted to the study of the contribution of the components of β-stable nuclear matter to the entropy per particle, a quantity of great interest for the study of structure and collapse of supernovas.

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