A New Nonlinear Stochastic Finite Element Method Based on Hermite Integrate

We apply the Hermite integrate to nonlinear stochastic finite element method, and establish the theory and algorithm of Stochastic FEM based on the Hermite integrate. An example is put forward, which is solved by choosing different kinds of integrate points and verified with Monte-Carlo stochastic FEM. The result show that the new method own a high efficiency. On the precision, the first and the second order quadrature reach high precision although the integrate points only is 3, however, the high precision of the third and the fourth order quadrature need more integrate points (e.g.11).     

Determination of Load Share between Gear Teeth with Contact Finite Element Method

The determination of load share between teeth is a complex problem in gear strength calculation. On the basis of contact finite element method this paper considers the production-assembly error as initial gap to get the finite element model which meets load share between teeth in gear meshing. Through calculating and comparing the result with that from ISO formula to get the load share between teeth which meets the requirements in actual usage.     

A New Method for Analysis of Interaction of Rock Mass with Multiple Cracks under Seepage Pressure

According to the theory of fracture mechanics, the mechanical model of rock-mass with multi-cracks under the action of seepage pressure was set up. Based on the principle of superposition, the formula for calculating stress intensity factor (SIF) was built. The stress intensity factor of cracks in different conditions, such as different crack distance, different crack angle and different seepage pressure, were discussed. It is suggested that, if distance between two cracks is short, the interaction of cracks has significant influence on stress field of crack tip. According to the change of relative crack location and crack angle, the different superposed stress can produce two effects, stress field strengthen and stress field weaken. The stress intensity factor would be increased when the crack tip is in the stress strengthen area; otherwise this value would be decreased. The interaction of adjacent cracks is related to the distance between two cracks. As the crack distance increases, the SIF is close to a fixed value which is calculated without considering the interaction between cracks. Therefore, when the crack spacing is larger than crack length, the interaction between adjacent cracks can be ignored. The results also show that the seepage pressure significantly affects the stress field near crack tip, and the stress intensity factor KI increases along with the increase of seepage pressure (-KI decreases).     

The Influence of In-situ Stress Gradient and Geothermal Temperature on The Calculation of Coalbed Gas Pressure

On the basis of coal seam having outcrop of coal seam and outlet on ground,the method for calculating coalbed gas pressure from the one-dimensional stable gas flow equation by considering deeply the influence of in-situ stress gradient and geothermal temperature is presented. In some mine, the theoretically computing and measuring results of coalbed gas pressure show that the in-situ stress gradient and the geothermal temperature have important influence on the calculation of coalbed gas pressure, and if the factors are drew into the calculation of coaled gas pressure,it will make the results much more accurate.     

Numerical Calculation Analysis About Seepage Field of Fine Grained Tailings Pool

The initially designed deposits of the Longdu tailings pool is the mixed tailings of iron ore and covelline. However, the fact that no iron ore tailings have been infused into the pool during its employment directly influenced its stability. By making use of 2D limited meta-softwares, the authors study the seepage features of Longdu tailings pool based on the tested data and material for it. According to first dam penetration, dry slope's length and different atmosphere rainfalls, the seepage field of the tailings pool is analyzed so they can conclude seepage rules for the fine grained tailings pool under different conditions and then study the stability features of the tailings pool. The result shows that change of the deposits gives ill effect on the stability of the pool, and the tailings pool will not run normally if no proper reinforce measure is taken in time.     

Mixed Finite Element Method for Dynamic Problems of Fluid Saturated Biphasic Porous Media

Based on the fluid saturated biphasic porous media model deduced from mixture theory,a finite element formulation with u S u F p variables for dynamic response analysis is given out.This method overcomes the difficulty of choosing suitable penalty parameter in penalty finite element method,and the accuracy of pressure distribution obtained with the mixed finite element method is higher than the penalty finile element method.An iterative solution method is suggested to solve the system of equations whose coefficient matrices are non positive definite.It is concluded from patch test that the order of interpolation function for pressure variables must be higher than that of displacement variables of solid phase.     

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.     

Analysis of the Static Stability of Tailings Dam under Coupled Deformation and Seepage Fields

The static stability of a tailings dam is analyzed with a finite element approach, which takes into account the effect of plastic deformation, temperature, saturation and void ratio on the properties of soil materials, the effect of water and soil interaction and the extended Mohr-Coulomb failure criterion. The concept of yield approaching degree is introduced, which is defined as the ratio of the existing equivalent stress to the yield stress taking into account the effects of different influencing factors. The response of the tailing dam subjected to the coupled saturated/unsaturated seepage and deformation is simulated, considering that the dry beach is 100-meter long and the starter dam is jammed, respectively. The important indexes such as the deformation and the phreatic surface of the dam are obtained. The distribution of the yield approaching degree in the whole dam under the given condition is obtained, which can provide not only a general stability assessment of the dam, but also important information to the decision-making for the reinforcement and maintenance of the dam.     

Numerical Analysis of Viscous Fluid Flow past a Circular Cylinder near a Plane with Boundary Element Method

The boundary element method was used for incompressible viscous fluid flow past a circular cylinder near a plane. The various phases of the flow passing the cylinder are studied numerically with different g/d. The numerical simulation of velocity fields is in good agreement with Davis' theoretical results and Taneda's experiments. In particular, the distributive curves of the surface force and the pressure on the circular cylinder were calculated numerically.     

Finite Element Analyses of Spherical Node of Coal Pipeline System of Blast Furnace

The mechanical model of spherical node of coal pipelines of blast furnace is built. Its boundary conditions and loads are presented. Its finite element analyses are used for this structure. Its stress distributing rules are obtained and the security of this structure is evaluated.     

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.     

Numerical Analysis of Acoustic Environment with Finite Element Method

The acoustic environment of highway tunnel is complex and has influences on the driving safety and comfort. In case of emergency, evacuation information is difficult to transfer. Finite element method is used for calculating highway tunnel acoustic modal and attenuation characteristics. The results show that acoustic mode of highway tunnel has symmetry in the horizontal pressure amplitude of symmetry regional is equal and phase is the same or opposite. The higher modal frequency, the greater sound pressure amplitude is, and the effect of tunnel length on modal frequency is smaller. Decay curves of pressure level at each point in the highway tunnel over time are nonlinear. After the source excitation, in 1.5 s, attenuation rate is faster than that of few seconds later and the attenuation time of sound pressure level 30 dB is 5.5 to 7 s.     

Analysis of Two Phase Flow Character of Test Well for Oil Extraction with Gas Lift Method

Numerical simulations are performed with RELAP5/MOD3.2 code to analyze the two-phase flow character of gas lift method in oil extraction. Gas lift startup and discharge are investigated with varying duty, and the result can provide the basis direction of oil well of simulation. code     

A Method of Solving the Structural Fuzzy Finite Element Equilibrium Equations

Based on resolution of interval numbers and fuzzy resolution theorem,we develop a method of solving the structural fuzzy finite element equilibrium equations. A lot of calculations and analyses show,the method presented in this paper is correct and feasible.     

Distributed Power Flow Method Based on Ward Equivalent

With interconnecting and developing of power system, the problem of power flow computation on dispersed data resource need to be solved. A new distributed computation method of power flow based on Ward equivalent is presented. According to master-slaver splitting principle, multi-area interconnected power system is divided into master-slaver areas. Boundary buses in different areas are defined as different bus-types. Neighborhood areas are equivalent by Ward equivalent principle, and the equivalent injection power and equivalent impedance are worked out. Power flows from master area to slaver areas are solved by Newton method, and the equivalent injection power and equivalent impedance on the boundary are modified by their solutions. The process above repeats until to convergence. The proposed distributed power flow method takes full advantage of the information of power, voltage, network configuration in neighborhood areas, so it is better on convergence and quality of solution. The proposed algorithm is testified by IEEE 14-bus system and a practical 181-bus system.     

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.