Papers by Keyword: Displacement Field

Abstract: The finite element model of runway is established based on elastic layered theory and it is used for analyzing the influence on mechanical responses due to changes of main landing gear configurations. The results show that the more the total number of wheels on a main landing gear is, the smaller displacement peak, maximum tensile stress under panel bottom and solid foundation influence depth are in conditions that aircraft loads are equal. When the landing gear spacing is smaller, the displacement curves in the loading area are gentler. The changes of configurations influence little on displacements in regions far away from loading area.

Abstract: In order to measure the displacement and strain field in the fatigue crack tip area of CT specimens under high frequency resonant loading condition in the fatigue crack propagation test, a method based on the digital image correlation (DIC) and digital high-speed photography technology are proposed in this paper. First, a series of digital speckle images of CT specimen under sinusoidal alternating load were collected by digital high-speed photography equipment, the displacement and strain fields within the region of crack tip in each image were calculated by DIC. The sinusoidal changing strain curve has been obtained by the least square sine wave fitting method, and the characteristic parameters of sinusoidal strain are calculated, such as the amplitude, frequency, phase, mean load . The images of characteristic position in one stress cycle were obtained by comparing the fitted sine curve of strain with the corresponding speckle images. Finally, the dynamic strain gauge was used to measure the strain at crack tip point during one stress cycle, and the accuracy and feasibility of DIC method were verified by the experimental results. The study result presented in this paper will supply a foundation for exploring the crack propagation law and measuring the fatigue crack growth parameters under high frequency resonant loading condition further.

Abstract: The landslide process and mechanism of rainfall-induced landslides are assessed by using particle flow code in two dimension based on the discrete element method. The formation mechanism of rainfall-induced landslide is revealed by the analysis of displacement field, velocity field and stress of the slope versus time. The fluid velocity and porosity of sample increase gradually with the increase of water head, the violent fluctuation of contact number of movable particles show the violent motion of slope, then the slope maybe slide.

Abstract: When crossing difficult terrain or extreme regional geological conditions encountered, there are difficulties in laying road routes, the spacing between two adjacent tunnels is limited. Neighborhood tunnel is a form of tunnel structure between separate and arch ones, less affected by the topography. It is more conveniently and easier to control the cost. Surrounding rock deformation mechanism with construction of three-step method is more complex, and therefore a reasonable means of construction technology and support is essential. Taking a certain neighborhood tunnel highway engineering background, aimed to provide guidance for follow-up monitoring and support, we use numerical simulation software FLAC^3D on three-step method excavation construction. Rational creep analysis of geotechnical model and calculation parameters is selected. It helps to calculation and analysis the mechanical response of tunnel surrounding rock characteristics and clarify the tendency of displacement and stress fields.

Abstract: The ABAQUS software is used for simulating the vertical bearing capacity of bucket foundation of different ratios of diameter to height and the analysis for the stress and displacement distribution and load-displacement curve. When the bucket foundation is under pressure, the vertical stress of the soil distribution changes from the bottom to the top, and then spreads to most part of the soil in the bucket foundation. The vertical displacement of the soil develops from the top of foundation and spreads inside, then expands to the outside range, the maximum displacement occurs both at the bottom and inside. According to the analysis of the ultimate bearing capacity of the bucket foundation, it could be found that when the height of the bucket foundation remains unchanged, the ultimate bearing capacity increases with the increasing ratio of diameter to height. If the ratio of diameter to height is less than 1.2, the ultimate strength increases significantly. If the ratio of diameter to height is greater than 1.2, the increasing speed of the ultimate bearing capacity changes slowly. When the diameter of the bucket foundation is constant, the ultimate bearing capacity decreases as the ratio of diameter to height gradually increases, and it decreases at a homogeneous speed. So the ratio of diameter to height 1.2 can be used as the optimum point of the ratio of diameter to height of the bucket foundation.

Abstract: Molded pulp pallet is a kind of new green material pallet which has a broad development prospects. In this paper, ABAQUS software was applied to simulate the situation that molded pulp pallet dropped from different heights in different ways. Stress field and displacement field of the pallet are obtained. Cushioning property and deformation of the molded pulp pallet were analyzed. The work of this paper could give a significant guide to design the molded pulp pallet.

Abstract: It takes the typical coal of mining in S₂S₉ face of Daping mine, using the 3-D numerical simulation to reveal on its face with the vertical characteristics of the stress field and displacement field .The study showed that the overburden strata migration features during the mining process in in thick seam mining of Daping mine.This research can be a reference for safety and high efficient coal mining of other parts of the soft overburden in extra- thick seam mining technology.

Abstract: Based on the application of the CSI non-contact full field strains and 3D displacements gauge made in USA in the laboratory for wind engineering of Southwest Jiaotong University, the theory of DIC, a non-contact deformation measurement method, is studied in the paper. The reliability of the method is testified by contrast tests. The paper also offers some useful advice byanalysing the factors that affect the measurement accuracy.

Abstract: The stability of tunnel surrounding rock is a key scientific issue in the design and construction of the tunnel engineering. Taking the load pattern of incremental form, the distribution law of stress and displacement field of the Osaka mountain tunnel after excavation was calculated based on the D-P yield criterion; Basing on the comprehensive heat and mass transfer theory, the temperature field in the surrounding rock was calculated and the variation of stress and displacement field after the surrounding rock experiencing the free-thaw cycles. All of the results can provide some references for the design and safe construction of the tunnel engineering under the action of freeze-thaw environment in cold regions.

Abstract: H-beam will inevitably produce temperature uneven in cooling process, causing the uneven deformation phenomenon in H-beam cross section, and therefore how to improve H-beam cooling distortion uniformity become a research priority of H-beam. In this paper, the deformation of H-beam was simulated in the cooling process by using finite element analysis software ANSYS, and the simulation results was compared with measured data. Uneven cooling rate between up and down groove of the H-beam caused the out of square. Uneven cooling rate for the R corner and web surface was simulated, the conclusion is that uneven cooling rate for the web is the main reason of the out of square, and that of R corner is the second factor.