Numerical Analysis on Stability of Rock in Sijiaotian Tunnel

The Sijiaotian Tunnel in Yunnan Dabao Highway lies in the narrow defile landscape,and the engineering geology condition is complex,with plenty of cienega.According to the actual situation of the Sijiaotian Tunnel Project in Yunnan Dabao Highway,the stability of the surrounding rock mass is studied by using a 3-D non-linear FEM.The Drucker-Prager criterion is chosen as the failure criterion of the rock.The relatively dangerous zone and the monitoring points in the tunnel are determined.The numerical results show that the Sijiaotian Tunnel is relatively stable.The conclusion has some significance for guiding the construction of similar projects.     

Finite Element Reliability Analysis of the Stability of a Slope

The whole reliability index of a slope is derived through using the strength reduction method in the finite element analysis, which can make use of the former finite element program and can be used to both linear and nonlinear finite element analysis. The affection of the evaluation of derivative and the selection of reliability analysis methods is discussed, which shows that it is very important to select the type of limit state function of the slope stability. A new iterafive formula, which can consider the correlation of fundamental parameters, is proposed for FORM, and the convergence is very well.     

Experiment and FEM Analysis on the Joint of Inserted Steel Beam

A new composite structure which is composed of steel beam and concrete girder is introduced in fuel electric plant construction. With different height of concrete girders with or without anchor bar, two scale models from an actual project were designed and tested. It is shown that the maximum restraining moment of ends of steel beams is approximately 60kN*m; influence of anchor bar is little; the one with 600mm high concrete beam is damaged by shear, and the others steel beam is damaged by bending failure. Finite element models were built for supplementary analysis, and the result indicates that critical value of the height of concrete beam of different failure modes is 700mm; stiffness of shear key and thickness of floor have great influence on the structure; size of anchor bar has little influence; and width of the end of the steel beam has certain influence.     

Nonlinear FEM Analysis of RC Staggered Joint by Using APDL Language

In order to settle some problems involved in applying ANSYS into nonlinear Finite Element Analysis of RC structure,this paper discusses the nonlinear FEM method for staggered joint,incorporating its experimental result.The main solved problems are as follows:(1) The fundamental process of nonlinear FEM analysis;(2) How to model the behaviors of reinforcement and concrete respectively;(3) How to model the bond-slip relationship between reinforcement and concrete.     

离散元法在农业工程领域的应用进展

简述了离散元法在农业工程领域方面的研究成果,根据离散元法在农业工程领域的不同应用,分别讨论了离散元法在土壤散体颗粒、农业物料颗粒、多相流中单相介质的应用研究现状,指出了存在数量级受限,颗粒模型不精准,复杂工况制约等问题。提出今后离散元法的研究趋势:开发农业工程领域的专用离散元软件,提高颗粒群的运算效率;通过准确获取物料的细观参数,从理论基础上完善接触模型,使仿真颗粒与真实颗粒更为接近;通过离散元法软件与其他软件耦合,结合API的二次开发,拓宽离散元法在复杂散体颗粒运动仿真的应用。     

Nonlinear Finite Element Analysis of Reinforced Concrete Transferring Joints with Inclined Columns

A nonlinear finite element analysis using ANSYS is applied to the vertical mechanical behaviors of three specimens of reinforced concrete transferring joints with inchned columns, which are used in high - rise buildings. A comparison is made between the analytical achievements and the test results, including the mechanical behaviors, load - transferring path and the failure modes, and a good agreement is obtained. The reliability of the software ANSYS in the nonlinear analysis of such reinforced concrete structures is verified and developed.     

Application of Matter Element Analysis in Assessment of Ambient Air Quality

A new method for assessment of ambient air quality is proposed by using matter element analysis.This model is simple and reasonable in assessment.The practical example is given,and compared with other methods.     

Analysis of Damage Localization in Crack Weakened Rock Mass

Damage localization in crack weakened rock mass is closely related to the crack growth pattern. Bifurcation of the alternative evolution of cracks occurs when the cracks grow to some extent, then some cracks keep on growing while other ceased evolving. It is found that damage localization in crack weakened rock mass is caused by bifurcation of the crack growth pattern, and the initial location is also determined by the crack growth pattern. Based on the analysis on the bifurcation of crack growth pattern, the critical length of wing crack and the critical stress of damage localization in crack weakened rock mass are obtained. Subsequently, the onset location of damage localization is determined by using the eigenvalue and eigenvector of coefficient matrix, and crack interaction is also taken into account in this model. Finally, the relationship between the interval between columns and rows, the orientation of crack, confining stress and the critical stress of damage localization is defined in the example.     

New Method to Study In-situ Stress of Rock Mass by AE and Structure Analysis of Rock Mass

In this paper, the authors adopt a method of structural analysis and stereography in combination with acoustic emission Kaiser Effect test in laboratory to find out the main direction of initial stresses. For overcoming the shortcomings of Kaiser effect by comparing it with traditional methods of measuring in-situ stresses, it is shown that this method is simpler, more economical and convenient for a large number of measurements and for studying the law of changes of regional in-situ stresses.     

Application of ANSYS to Finite Element Analysis for Nonlinear Masonry Structures

ANSYS has become an effective tool for finite element analysis of masonry structure, but there is few common conclusions for reference. According to the characteristics of ANSYS and the essence of the analysis, some key problems in finite element analysis of masonry structure with ANSYS, such as structural modelling, material constitution, the damage criterion, iterative algorithm, convergence criterion, simulation of prestressing force and so on, are discussed in this paper. Based on the test results of typical masonry structures, the applicability of ANSYS to masonry structural analysis is studied and some suggestions for the application of ANSYS are presented.     

Analysis of the Coupling Modeling Method with CATIA-FLAC 3D and Its Application

Numerical models based on FLAC 3D are difficult to build. A new kind of method modeling and meshing in the CATIA software, named the CATIA-FLAC 3D coupled modeling method, was proposed. This method utilizes the powerful geological modeling capabilities of CATIA for three-dimensional geological body modeling and meshing. And then, the interface program of CATIA-FLAC 3D is adopted to export the information into FLAC 3D, which is coded by visual basic language based on the variance of nodes and elements between the two software. The new proposed method was used in a bias tunnel through a mountain, and the results verified the feasibility and effectiveness of the proposed method.     

Using the Finite Element Method to Predict the Dispersed Shrinkage and Hot Tearing of the Pump Shell Castings

This paper has simulated numerically the 2D temperature field and stress field of main circle pump shell steel castings of nuclear power plant by finite element method,predicts the dispersed shrinkage,shrindage and hot hearing.The real dissecting pouring castings had the same results as the numerical simulation.At the same time the authors evaluat the molding design of the pump shell castings.     

Application of Extended Finite Element Method to Fracturing Analysis of Gravity Dam

The extended finite element method(XFEM) presented in recent years is a new and effective method for discontinuity analysis,especially fracture problem analyses.The basic XFEM principle is introduced and the technique for fracture analysis is presented.The fracturing process of a gravity dam is simulated by XFEM,and the rules of stresses and displacements distribution are analyzed.Compared with the classical finite element method,the crack growth in the gravity dam can be modeled by XFEM without making the crack surface associate with the finite element mesh and setting dense mesh near the crack tip as well as remeshing after crack growth.The cumbersome work and disadvantages in conducting fracturing analysis by the finite element method thus can be avoided.The predominance of this method for dam fracturing analysis is displayed.     

Design Method for the Individual Anatomical Hip Joint Endoprosthesis

A new design method for the individual hip joint endoprostheses is proposed. By picking up the contour lines from the femur's CT images and making them closed and smoothed, a solid model of the femur is reconstructed using the contour lines by CAD software. An individual anatomical hip joint endoprosthesis is designed with the inner contour curves of the medulla cavity in CAD software. Utilizing the APDL(ANSYS Parametric Design Language) and the CT value per pixel in the CT image for developing a program through which every element of the bone can get its own material property. The finite element model's anisotropy and inhomogeneity of bone material are realized, then the endoprosthesis and the femur-stem contact finite element model can be built in ANSYS. Based on this, calculation on the contact model can be processed. It is feasible to checkout the rationality of the design by comparing the stress distribution in the femur with the situation before replacement. And the results reveal that the method is more reasonable and reliable.     

Finite Element Analysis on Interaction of Neighboring Highway Tunnels under Construction

Recently, the construction of neighboring highway tunnels with small interval gets more and more in China. The construction of such tunnels proceeds usually by excavating one after another. The second tunnel is constructed with the surrounding rock disturbed by the first one. And the construction of second tunnel also has effect on the first excavated one. For revealing the interaction laws of such tunnel construction in combination with the engineering practice of Lanfeng tunnel at Jinshan Road in Chongqing, The FE numerical simulation analysis was used to study the characters of surrounding rock deformation, stress field, and plastic zone of the tunnel. From this analysis, it clearly shows that the excavation of second tunnel has significant influence on the first one. This study provides a scientific basis for design and excavation of neighboring highway tunnels.     

Application Research on Vehicle Handling Stability Using Simulative Analysis

A multi-body simulation approximate model of a vehicle using ADAMS software is established, and a frontrear suspension system, a steering system, the tires and all connectors are studied. Vehicle handling stability under different tests is simulated. The result is credible and valid, the parameter of vehicle model is amended expediently. This simulation can help design products and reduce a development cycle.     

Numerical simulation of remodeling in mandible under orthopedic loads

The research on the remodeling in mandible under the action of orthopedic loads is important for the determination of orthopedic scheme. a three-dimensional finite element model of mandible and temporomandibular joint is established. Using Cowin Remodeling Law, the finite element simulation of the remodeling in mandible during the orthopedics under the action of orthopedic loads is carried out. Comparing the numerical results after remodeling with those before remodeling, it is demonstrated that the normal remodeling greatly affects the distribution of strain and strain gradient on the surface, therefore the effect cannot be ignored in the determination of the orthopedic scheme.