Papers by Keyword: Shearing Stress

Abstract: nanocrystalline cellulose (NCC) was prepared from micro-crystalline cellulose (MCC) by strong acid hydrolysis. The characteristics of such particle were studied by transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. Electro-rheological fluids (ERF) were prepared by dispersing NCC and MCC in methyl-silicone oil, and their ER effects were measured. Experimental results indicated that NCC ERF exhibited a remarkable ER effect. The highest static shearing stress of NCC ERF (3.5 g/ml) was 5.1 kPa at the room temperature under a 4 .2 kV/mm electric field, increased about 5.5 times compared to MCC ERF, and sedimentation of NCC ERF was not observed even after 60 days.

Abstract: The dynamic evolution mechanism of dislocation under shearing stress which was the main influences of damping performance in the inner space of magnesium alloy was studied. Firstly, the inner shearing stress and its distribution of the rectangular magnesium alloy beam was calculated while the beam was bending;Secondly, the breeding and networking model of dislocation under the action of shearing stress was constructed;Finally,combined with the practical observed dislocation morphology, clarified the dynamic evolution mechanism: Under the shear stress, through F-R dislocation breeding and extension as well as twisting of dislocation with different dislocation sources under subsequent breeding, the dislocation cellular network structure is formed, which is of approximate honeycomb structure.

Abstract: Magneto-rheological grease attracts the attention as a new kind of intelligent material. Under the external magnetic force, it is difficult to use traditional mathematics model to solve and analysis internal structure because of its complexity and polytropy. The modeling and simulation for complex system using computer becomes a good way to investigate complex system. Based on the electromagnetic theory and computer simulation, this paper constructed the model of shear stress to describe the characteristic of magneto-rheological grease that is to use body centered cubic pillars model to analysis the mechanism and characteristics of magneto-rheological grease. Using matlab simulink toolkit to compose the simulation program, simulate and analysis using theoretic model, and plot the shear stress curve of magneto-rheological grease with magnetic strength and particle size, and the shearing force under zero field. The simulation and experimental results indicate that the simulated shear stress curve is coincidence with experimental curve when the density of ferromagnetic particle is low, and it is lower than experimental curve when the density is high (the variation tendency is close), which verified the accuracy of theoretical model. It needs to improve the model by considering the still friction between ferromagnetic particles.

Abstract: To find the effects of pedoturbation on soil erosion of lands for agriculture and forestry in Menglianggu watershed of Linyi city from soil mechanics, shear strengths of 3 typical land uses (6 different soils) which are undisturbed and remolded respectively were measured by direct shear apparatus. Effects of particle size and binding materials on shear strength were analyzed by comparing shear properties of undisturbed and remolded soils with the same dry density, water content and vertical loads. The results show that all the angle of internal friction ( ) and most of soil cohesion ( ) of undisturbed soils are bigger than that of remolded soils; The final shearing stress also comply with the law above; The main factors affecting shear strength are soil particle size and binding materials.

Abstract: In order to study the shearing stress of asphalt surface on lean concrete base, first of all, three–dimension finite element model of the asphalt pavement is established. The main objectives of the paper are investigated. One is calculation for shearing stress of asphalt surface in transverse contraction joint of lean concrete base, and the other is analysis for relationship between load stress of asphalt surface and parameters, such as thickness, modulus. The results show that maximum shearing stress, which is caused by load, is evident in asphalt surface which is located in transverse contraction joint of lean concrete base of asphalt pavement. Maximum shearing stress decrease, decrease, decrease and increase respectively with increase of the surface’s modulus, the surface’s thickness, base’s thickness and ratio of base’s modulus to foundation’s modulus.

Abstract: At the beginning,we used the ABAQUS to establish a two-dimensional finite element model of typical asphalt pavement, and analysised the changing axiom of road surface shearing stress under the half sine wave load. Also, we studied on the impact of damping ratio and the driving speed on shearing stress. Finally, by using SPSS13.0 software to compare the impact of speed, the surface layer material damping ratio, lower modulus ratio, the thickness of the surface layer and the thickness of the subbase. The results show that, to reduce the cracking damage caused by oversized shearing stress in asphalt pavement, we should first consider the damping ratio of surface layer material, and the most effective method is to use the road-building material of high damping ratio to prevent cracks, at the same time we should raise the driving speed.

Abstract: Fully grouted bolt has been in wide use as a kind of support in geotechnical engineering. But the design method and application for fully grouted bolt is limited due to the shortage of its anchorage mechanism and mechanical behavior at present. So in this thesis an in-depth exploration of anchorage mechanism and mechanical behavior of fully grouted bolt will be done starting from the study of mechanics mechanism of fully grouted bolt, the result will provide reference for the design and application of fully grouted bolt and this have value of theory and engineering.

Abstract: Measurement of shearing stresses, τ_xz and τ_yz, by X-ray diffraction technique with two-dimensional detector was studied. The principle which was developed for an area detector type X-ray triaxial stress analysis was adopted for this purpose. In the present method, Debye ring was measured first and its whole part was used for determining shearing stresses. One Debye ring is enough to determine shearing stresses without accurate diffraction data such as lattice spacing in stress free. The result of the simulation showed that the present method is useful for the evaluation of shearing stresses by X-ray diffraction technique.

Abstract: An interfacial shearing and peeling stress model is proposed to account for different uniform temperatures and thickness wise linear temperature gradients in the layers. This upgraded model can be viewed as a more generic form to determine interfacial stresses under different temperature conditions in a bi-layered assembly. The selected shearing and peeling stress results are presented for the case of die and die attach as commonly seen in electronic packaging. The obtained results can be useful in interfacial stress evaluations and physical design of bi-material assemblies, which are used in microelectronics and photonic applications.

Abstract: Graded broken stone materials show cross-anisotropic behavior, but now most pavement structure analysis are based on assuming pavement structure to be isotropic layered system. In order to accurately evaluate pavement responses based on cross-anisotropy utilizing graded broken stone as sub-base materials, the influences of sub-base thickness, horizontal modulus and breaking force on the stress in pavements are studied by using the three-dimensional finite element software ABAQUS. The results show that the shear stress of the pavement decreases with the increasing of the sub-base thickness or the horizontal resilient modulus but the shear stress of the pavement increases obviously with the increasing of braking forces.