A Finite Element Method for Quasi Static Problems of Two phase Porous Media

For the quasi static problems of two phase porous media,the velocity variable of fluid phase can be eliminated as the viscosity of fluid is neglected.The corresponding governing equations,with displacement of solid phase and pore pressure as basic variables,as well as the boundary and initial conditions are given out.Finally a mixed finite element formula with u S-p variables is obtained with weighted residual method.This method has lesser nodal variables and higher accuracy of pressure distribution.     

Mixed Finite Element Formulation of the Linear Biphasic Theory for Soft Tissues

The behavior of soft tissues of human musculoskeletal system can be describedwith the biphasic model based on a continuum theory of mktures. This paper. using Galerkin weight-ed residual method.obtains a mixed finite element formulation for the linear biphasic model of smalldeformation. and. in turn. gives out the iterative scheme solving the system equations. The results ofnumerical analysis for the constrained compression problem are consistent with those obtained bytheory. which illustrates the correctnas and feasibility of the derived mixed finite element formula-tion. concludingly. this formulation provides an effective means of numerical analysis for the motfonmechanism of human articulating joints.     

Wave Propagation Behavior in Saturated Porous Media

In this paper, an attempt is made to discuss the wave propagation behavior in saturated porous media with the decomposition of the motion equations. And it is denoted that there are two types of dilatational waves and one rotational wave. Also, the motion equations of the different waves are obtained, and the wave velocities in some special cases are calculated, from which it is concluded that permeability of media greatly affect wave propagation behavior.     

Dynamic Constitutive Model of Steel Fiber Reinforced Concrete and Its Finite Element Method

Taking the split Hopkinson pressure bar(SHPB) test data as training samples, an implicit dynamic constitutive model of steel fiber reinforced concrete(SFRC) was proposed with the improved BP neural network program. On the basis of ABAQUS/Explicit, a user defined material subroutine VUMAT was compiled with FORTRAN language, embedding with the neural network constitutive model into finite element calculation. With SFRC structure＇s response under impact load as case study, it is shown that the constructed constitutive model and its finite element method are effective.     

Hyperelastic Constitutive Relations and Finite Element Formulation for Porous Silicone Rubber

The strain energy density function which was decoupled into isochoric parts and volumetric parts is presented for describing mechanical behaviors of compressible porous silicone rubber material,the constitutive model is then attained.The finite element formulation for isotropic hyperelastic porous silicone rubber is developed by use of total Lagrangean method.     

Three Dimensional Eddy-current Field computation by Edge Finite Element Method of Mixed Elements

The edge finite element interpolation function of 1-forms for prism is derived.The electrical field intensity is used as the unknown variable.If the tangential component of electrical field intensity is an enforcing condition on the interface of eddy-current region and non-eddycurrent region,the tangential component of magnetic field intensity is a natural continuous condition.At last,the mixed elements of prism and hexahedron are used to compute a three dimensional eddy-current problem.     

Finite Element Method of 3D Stable Heat Conduction of Steel Fluid in Continuous Casting Moulds

The heat transfer of steel fluid in continuous casting mould is a stable process and can be depicted with three-dimensional stable heat conduction equation depending on tension speed. The corresponding finite element equation, including the first, second and third boundary conditions, is deduced out with Galerkin residual method. The coded FEM program is used to analyze the temperature distribution of Q235 steel in continuous billet casting mould. The method proposed is a foundation of thermo-mechanical coupled analysis for the formation of solidified shells and stress in the shells in continuous casting.     

Applying the Dynamic Condensation Technique to the Mechanical Structure Finite Element Modeling

Research for applying the technique of dynamic condensation on the mechanical structure dynamic analysis.The tolerance of the mechanical structure dynamic characteristics has been investigated when it is solved with the useful method of mode condensation.The practice shows that computational result of the dynamic characteristics relating to reserved number of mode and the magnitude of the damping,when the freedom of the complicated mechanical structure finite element model be reduced in big amplitude with the mode condensation technique.     

The Finite Element Method for Frame Structure with Fuzzy Elastic Connections

The connections of frame structure elements at a node are ofen an elastic connection between hinged and rigid.In this paper,the stiffness matrix and the loading transfer matrix of frame element with turn elastic connections is deduced,the cross shear effect has been taken into consideration simultaneously.The stiffness matrices of some bar elements,such as both ends of the bar are hinged or rigid and one end is hinged but the other is rigid,are special cases of the stiffness matrices presented in this paper.After pointing out that the elastic coefficient at a node of a bar element with elastic joint is really a fuzzy quantity,the fuzzy stiffness matrix of the bar element is obtained,and a solution to structural fuzzy finite element equilibrium equations is presented.The fuzzy solution obtained from above is not only containing the solution of ordinary finite element method but also providing some additional informations with practical value.[WT5HZ]     

Coupled Thermo-Elastic Contact Finite Element Method and It''s Application in Gearing

A new finite element method is presented in this paper to analyze the thermo- elastic contact problem with heat input on meshing tooth faces. The computational model of meshing gear has been established and the frictional heat input on meshing tooth faces is estimated. In addition, 2-D finite element analysis program for this kind of problem is listed. The test and practical examples are given to show the validity and versatility of this method.     

Post-process of Finite Element Method in Electrical Impedance Tomography

In the research of electrical impedance tomography (EIT), each calculation may produce a large amount of data(such as conductance , resistance etc.). The rule of these data is not clear and is hard to understand. How to express the calculation result by means of image in order that such parameters as conductance and resistance can be grasped from the image is significant in analyzing and understanding the calculation result and is helpful to the doctor. This paper has discussed the realization of the post-process of finite element method in electrical impedance tomography and we have developed the software of the post-process of finite element method using Visual C++ .NET and OpenGL. Some problems in drawing the contour line and color contour band have been solved properly.     

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.     

Finite Element Analysis of Masonry RVE Homogenization Procedure

Homogenization is one of the most important steps in the numerical analysis of masonry structure, where the continuum is used. A masonry representative volume element (RVE) is formed as the equivalent element of masonry components and it is the most important step in homogenization procedure. The RVE is molded with consideration of the material properties of mortar and brick as well as their interaction separately. In this paper the masonry RVE is simulated with the finite element software ANSYS. The stress-strain relationships of RVE subjected to different types of loading conditions are presented. The equivalent elastic modulus and Poisson's ratio are calculated and the feasibility of finite element method used in the procedure of masonry homogenization is demonstrated.     

Numerical Analysis on Dynamic Response of Saturated Elasto viscoplastic Soft Clay

In the framework of porous media model developed from mixtures theories, Solid skeleton of soft clay was viewed as elasto viscoplastic material,and an elasto viscoplastic model of saturated soft clay was established. According on the model of saturated so     

Section Optimization Design of Steel-Concrete Continuous Composite Beams Based on the Finite Element Method

This paper introduces the efficient computer aided design method to optimize the section of steel-concrete continuous composite beams by combining FEM for structure analysis with optimization arithmetic and an efficient shearing force link model of steel-concrete composite beams.The authors established a finite element analysis model,optimization parameter model,optimization mathematics model of steel-concrete continuous composite beams and programs analysis file and optimization control file by using the ANSYS parameter design language. The optimum of the steel-concrete continuous composite beams section is obtained after computing and the optimization result indicates that this method is efficient in optimizing the section of steel-concrete continuous composite beams.So it could be applied extensively in the steel-concrete continuous composite beams section optimization design.     

Study on Heat and Moisture Transport Properties of Moist Porous Media

By analyzing heat and mass transport process and transport properties of moist porous media, this paper established a computational model for one dimensional field of heat and moisture transport process. Based on the distinguishing characteristic functions, the inner temperature and humidity distribution of porous media was worked out. With the actual spot measurement, the heat and moisture properties were obtained by nonlinear least square method.     

Finite Element Analysis of Spatially curved Rods

A system of governing equations for spatially curved rods are derived in natural coordinate,and an analytic solution to the statically determinate problem is given.Based on the solution,a generalized displacement model for element of curved bars is developed,which is convergent and accurate.