Applied Mechanics and Materials Vols. 670-671

Abstract: This paper presents a consistent theoretical framework for describing the finite poroelasticity with surface effect. The underlying concept of additional pressure that is thought of as an equivalent thermodynamic pressure applying on the pore surface is used to detail the pore pressure. A nonlinear porosity laws is proposed for the finite deformation of porous material. With surface effect consideration, the corresponding constitutive equations are developed. The present model for both the swelling of the matrix and the permeability change of coal induced by adsorption of CO₂ and CH₄ are presented under different pressure conditions. It is shown that the predictions from the model are good agreement with the experimental data of sorption-induced deformation of coals.

Abstract: With the development of 300m super-high dams are built in the southwest of China, reservoir water gravity will make the settlement of the reservoir basin, which will make dam tilt upstream. In the paper, reservoir settlement will be studied in-depth on the basis of monitoring data analysis and numerical simulation comprehensively. First, reservoir basin will be sinking with the rising of the upstream water gradually according to level monitoring data. Second, those affect factors of FEM calculation have been explored comparatively, such as displacement modes, element geometry and boundary conditions. Third, reservoir, dam and foundation are integrated into a whole to establish a wide spread finite element model. At last, reservoir deformation and its influence factors are determined through the simulation of the bedrock depth, the extending length of the upstream and downstream and different water levels. Those methods have been applied into an engineering project and analysis results show that the settlement of the reservoir will make high arch dam tilt upstream, the higher of the water level, the larger of the horizontal displacement. Accordingly, reservoir deformation should be considered deeply on the appraisement of super-high arch dam operating status in future.

Abstract: For the hydrocyclone’ separation efficiency affects by many factors, this paper combined Reynolds stress model and SIMPLEC algorithm of Fluent software with orthogonal test to simulate hydrocyclone’s operating process and analysis the flow field. Different overflow pipe wall thickness values (4mm, 8mm, 12mm), volume fraction values (1%, 5%, 10%) and inlet velocities (3m/s, 4m/s, 5m/s) was considered as the separation efficiency affective factors. Results show that the overflow pipe wall thickness has greatest influence on separation efficiency. The inlet velocity is the second and the volume fraction value is the last. The optimal combination is the overflow pipe wall thickness value 8mm, the volume fraction 5% and the inlet velocity 5m/s. The overflow pipe wall thickness value increasing can decrease the turbulent kinetic energy and increase the stability of hydrocyclone flow field.

Abstract: The immersed boundary method (IBM) for the simulation of the interaction between fluid and flexible boundaries in combination with the lattice Boltzmann method (LBM) is described. The LBM is used to compute the flow field, the interaction between fluid and flexible boundaries to be treated by the IBM. To analyze the key factors of combination method and implementation process. An example is presented to verify the efficiency and accuracy of the described algorithm. These will provide a base for large scale simulation involving flexible boundaries in the future.

Abstract: In this work, the influence of a rigid cylindrical inclusion on the elastic field in a transparent soft material is studied by an embedded-grating technique. The same experimental procedure was implemented on two specimens, a homogeneous bulk soft material and the same material containing a rigid cylindrical inhomogeneity. Under the indentation of a rigid wedge, two kinds of deformation sectors underneath the contacting boundary are observed from experimental results. Furthermore, the shape of the deformation sectors is horizontally expanded due to the inclusion. A local fluctuation of contact stresses between the soft matrix and rigid inclusion are discussed.

Abstract: A three-dimensional numerical model of the rock mass including ore body is established by FLAC3D software, and then the surface subsidence caused by backfilling under different roof thicknesses of mining stope (the vertical distance between upper mining limit and surface) are calculated and analyzed. By comparing the surface displacement, the stress distribution, and the damage zone under different conditions, the minimum roof thickness is determined.

Abstract: This paper focused on groundwater flow in certain a tunnel site under conditions of high ground stress and high water pressure (referred to as “two high conditions”). Three-dimensional conceptual model was established for groundwater flow in porous strata with argillation weak permeable media in a long deep buried tunnel site. Groundwater flow field was studied by means of three-dimensional numerical simulation. Results show that there is good agreement between numerical simulated and observed groundwater table and that the conceptual model and the numerical simulation are reliable. Prevention measures should be adopted for a long deep buried tunnel construction. The results can provide evaluation of engineering safety of a long deep buried tunnel construction with scientific basis.

Abstract: This paper presents a percolation model for the composite reservoir, in which quadratic-gradient effect, well-bore storage, effective radius and three types of outer boundary conditions: constant pressure boundary, closed boundary and infinity boundary are considered. With Laplace transformation, the percolation model was linearized by the substitution of variables and obtained a boundary value problem of the composite modified zero-order Bessel equation. Using the Similar Constructive Method this method, we can gain the distributions of dimensionless reservoir pressure for the composite reservoirs in Laplace space. The similar structures of the solutions are convenient for analyzing the influence of reservoir parameters on pressure and providing significant convenience to the programming of well-test analysis software.

Abstract: This paper presents the analysis of the spacecraft with fuel sloshing during attitude maneuver. The fuzzy sliding mode controller is designed for a simplified model of the spacecraft. The controller includes an equivalent control term, a sliding controller, and an optimal controller by adaptive fuzzy algorithm for perturbation parameters. Extensively numerical simulations are carried to verify effect of the control method in this paper and the numerical results show the good performance and better effectiveness for the fuel-filled spacecraft large attitude maneuver.

Abstract: Using ANSYS software comes with parametric design language APDL, developed a square pyramid partial double layer of Schwedler spherical reticulated shell parametric design macro program; achieved this kind of spherical shell parametric modeling with the given shell span S, vector high F, the thickness (height) of the pyramid, ring copies of the symmetric region Kn and radial nodes laps Nx. Analyzed the static performance of the spherical reticulated shell under different structural parameters, studied the displacement of the structure and the distribution of the stress change with macroscopic geometric parameter change rule. Analysis results of eight kinds of conditions showed that the square pyramid partial double layer of Schwedler spherical reticulated shell has good mechanical performance. The result of the analysis provides a theoretical basis for the relevant engineering design.