The damage constitutive relation of entire rock failure process was established using the theory of representative volume element obeying the Iognormal distribution law, and the integrated damages constitutive model o...
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The damage constitutive relation of entire rock failure process was established using the theory of representative volume element obeying the Iognormal distribution law, and the integrated damages constitutive model of rock under triaxial compression was established. Comparing with triaxial compression test result, it shows that this model correctly reflects the relationship of stress-strain. At the same time, according to the principle of the rock fatigue failure that conforms to completely the static entire process curve, a new method of establishing cyclic fatigue damage evolution equation was discussed, this method form is simple and the physics significance is clear, it may join preferably the damage relations of the rock static entire process curve.
The stability of rock-mass slopes is a very complicated system which is controlled by lots of factors. It is always a very important research subject to evaluate the slope stability reasonably through some evaluation ...
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The stability of rock-mass slopes is a very complicated system which is controlled by lots of factors. It is always a very important research subject to evaluate the slope stability reasonably through some evaluation methods. Based on matter-element theory and dependent function, the extension theory is applied to evaluate the stability of rock-mass slope, and the extension method for the stability of rock-mass slopes is proposed. Taking a real slope project for example, based on the reasonable selection of evaluation factors of slope stability, an extension model for evaluation of slope stability is built, whose result is contrasted with the fuzzy evaluating one. As a result, it is practical and feasible to apply the extension method to estimate the rock slope stability.
The authors developed a computer program of transient predictive calculation method on underground ventilation network. The program approximated a field data set of seasonal cyclic changes of air Temperature and humid...
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The authors developed a computer program of transient predictive calculation method on underground ventilation network. The program approximated a field data set of seasonal cyclic changes of air Temperature and humidity at the inlet to the sine curves, and included sensible heat conduction from rock to air current. The temperature of rock around and airway was calculated by finite difference method. The prediction method can be used to calculate the variation of flow rates, temperatures and humidities of air flow in the airways along underground network.
Magnetorheological fluids exhibit fast, strong and reversible changes when a magnetic field is applied, making them very interesting for a lot of technical application. Magnetorheological fluids change from Newton flu...
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Magnetorheological fluids exhibit fast, strong and reversible changes when a magnetic field is applied, making them very interesting for a lot of technical application. Magnetorheological fluids change from Newton fluids to Bingham fluids and start to flow when the shear stress is up to yield stress under the applied magnetic field. Based on physics and fluid mechanics, fluid dynamics model is presented using the method of continuum to analyze flow field with the influence of a magnetic field. The model can show the influence of magnetic field on flow field.
Magnetorheological (MR) dampers take advantage of the particular magnetorheological effect to work, which are widely applied for technical engineering. Generally as a viscous fluid, the mechanical model of the flow of...
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Magnetorheological (MR) dampers take advantage of the particular magnetorheological effect to work, which are widely applied for technical engineering. Generally as a viscous fluid, the mechanical model of the flow of MR fluid is established and the flow is analyzed in the design of MR damper. There is much difference between the theoretical result and experimental one. The dynamic model for MR fluid as viscoplastic fluid is presented to analyze the flow of MR damper, which provides a foundation for the design of MR damper.
The current progress in porous metal-organic coordination polymers (MOCPs) built by the chelate bonds between center metal ions and ligands is reviewed according to the ligand types in this paper. It is pointed out th...
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The current progress in porous metal-organic coordination polymers (MOCPs) built by the chelate bonds between center metal ions and ligands is reviewed according to the ligand types in this paper. It is pointed out that a lot of structure data have been accumulated by many research groups through their efficient jobs in the MOCPs synthesis since the materials became a hotspot in 1990 s, but there is some shortage in the research of the relationship between the regulab.e superiority in pore structure and their applied properties, like molecular identification, shape-selecting adsorption or catalysis, etc. And the structure-effect relations are just the most remarkable of the materials.
This paper has probed into the evolution of the hysteresis curve of rock under the cyclic loading by the experimental research on the deformation characteristics of sandstone under cyclic loading in three axial stress...
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This paper has probed into the evolution of the hysteresis curve of rock under the cyclic loading by the experimental research on the deformation characteristics of sandstone under cyclic loading in three axial stress levels. The research results have been indicated as follows on whether the hysteresis curve change will depend on the stress level: when the stress level is low, the acreage closed in the hysteresis curve will go invariable with the increase of cyclic count, but when the stress level is high, the acreage closed in the hysteresis curve will be variable from decrease to unchange and then to increase with the increase of cyclic count.
The method for extracting velocity field is mainly investigated and the image-processing system of two-dimensional Digital Particle Image Velocimetry (DPIV) is developed. The algorithm is based on gray image cross-cor...
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The method for extracting velocity field is mainly investigated and the image-processing system of two-dimensional Digital Particle Image Velocimetry (DPIV) is developed. The algorithm is based on gray image cross-correlation and the most similar sub-windows on the two frames in serial gray images are reckoned as optimal matching. The displacement of the particle movement on image plane is thus determined by the distance of the two centers of sub-windows. On basis of large amount of experimental results, the normalized cross-correlation coefficient is selected as the cross-correlation measure, which greatly reduces the computational time and meanwhile holds the particle matching accuracy. Moreover, the search regions are optimized to reduce time consumption. The experimental results of standard images as well as the successful application in the actual experiment of oxidation ditch model prove that the researched algorithm of velocity extraction is suited for the measurement of the flow field such as oxidation ditch model.
In this paper, integrating the principium of demolition blasting of buildings and the practice, the general mechanism and affection factors of blasting harms such as blasting shock, collapsing shock, blasting rock, bl...
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In this paper, integrating the principium of demolition blasting of buildings and the practice, the general mechanism and affection factors of blasting harms such as blasting shock, collapsing shock, blasting rock, blasting shock wave and blasting noises produced in demolition blasting of buildings are analyzed. The safety problems which existed in demolition blasting of buildings are discussed from three aspects such as the unsafe behavior of 'person', the unsafe state of 'substance' and the unsafe condition of 'environment'. Based on an engineering example, the difficulty of safety blasting of engineering example was analyzed, on this basis, corresponding effective safety defending measures and the method of safety control are brought forward. This study is significant to the construction safety and control of demolition blasting of similarity tower building in practice.
Based on the microstructure-mechanisms of rock materials and a simple mechanical model, a rheology damage constitutive equation is proposed by introducing generalized time defined in the space of irreversible strain a...
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Based on the microstructure-mechanisms of rock materials and a simple mechanical model, a rheology damage constitutive equation is proposed by introducing generalized time defined in the space of irreversible strain and Newtonian time, and an anisotropic damage tensor of rank four. The anisotropic evolution and unilateral effect of damage as well as the effect of hydrostatic pressure' can be taken into account in the proposed model. The corresponding numerical analysis is developed;and the creep, inelastic and damage behaviors of claystone are analyzed. It shows that the calculated results agree well with the experimental observation. The influence of stress level on the creep can be well described with the model.
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