AUTOMATIC MESH GENERATION SCHEME IN FINITE ELEMENT CONTACT ANALYSIS OF MESHING GEARS

In this Paper, a new automatic mesh generation scheme is present, which combine the teeth contact analysis with the modelling of finite element cotact analysis. This procedure is different from the ordinary auto - mesh - generation scheme. The presentation of this new procedure makes it possible to analyze the elastic contact problem of meshing gears by a finite element method.     

A Boundary Element Separation Solution to the Elastic Contact Problems and the Optimal Penalty Factor

In this paper the boundary element separation to the elastic contact problems proposed by Kamiya is improved. It gives another optimal penalty factor to accelerate the iteratively saluting procedure, which makes a theoretical foundation for the application of computers' parallel processing method to reduce the calculation time and memory. A practical example is given to confirm the validity of the present method in comparison with Kamiya method.     

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.     

Three-dimensional finite element analysis for thermo-elasto-hydrodynamic performances for a water lubricated bearing system

Three-dimensional liquid-solid coupling finite element analysis for thermo-elasto-hydrodynamic performances for a water-lubricated bearing system is conducted using finite element code, based on the influence coefficient method, and nonlinear optimization method. Meanwhile, the code is validated. Numerical results show that significant elastic deformation and thermal deformation, contact pressure with certain amplitude, and large temperature rise over the range of the small film thickness-roughness ratio can occur for the bearing. Therefore, the above deformation and temperature rise should be considered in designs and applications of water-lubricated bearings.     

Force Analysis on Meshing Surface and Stress Research of the Cone Roller Enveloping Worm Gearing Transmission

By using the finite element elastic contact analysis method combined with the I-DEAS engineering analysis software, this paper studies the strength of the cone roller enveloping worm gearing,which is a new type of worm gearing transmission,on SUN-4 working station. It also analyzes loading distribution among meshing gears, the contact force distribution along the contact line ,the bending stress distribution and the contact stress distribution of the cone roller enveloping worm gearing with three-tooth meshing instantaneously. Besides,it provides the theoretic basis in the further researches for the new type of worm gearing transmission.     

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]     

THE METHOD AND ITS APPLICATION FOR COUPLED ANALYSING PLASTIC DEFORMATION OF ROLLING WORKPIECE AND ELASTIC DEFORMATION OF ROLLS

A method for coupled analysing plastic deformation of rolling workpiece and elastic de'formaticn of rolls is developed. The interaction of plastic defo rmation of rolling workpice and elastic deformation of rolls is considered. The couple is formulated by setting up force equilibrium equation at the interface of the rolling workpiece and tne rolls. The plastic deformation of rolling workpiece is treated by the rigid plastic finite element method and the elastic deformation of rolls is treated by the boundary element method. The rolling presure, perunit. forward slip, neutral from angle obtained from coupled analysis are lower than those obta-ined rigid rolls. The results obtained from analysis show that the analytical accuracy can be heightened using the coupled ana-ytical methcd dveeloped for treatng rolling3proccss.     

Numerical simulation of contact problems in high pressure reciprocating pump systems

The cylinder bodies of reciprocating pumps easily fail from cracks due to complex external loads. Based on the working principle of reciprocating pumps, hydrodynamics, and a numerical method for surface to surface contact problems, a contact model involving a cylinder body, a valve base, and a valve pocket is established. Considering pressure fluctuation, flow pulsation, alternate loads, and the impact of the inlet and outlet valves, a finite element model for the complete system is established. Using this model, the contact state of the complete system is analyzed, and the stress distribution, contact state, contact stress distribution of the interface, and position of the weak part are obtained.     

对偶性与特大增量步算法在复杂平面框架中的应用

特大增量步算法（LIM）是一种基于力法和广义逆矩阵理论的迭代算法，在简单桁架和刚架非线性初步应用中，达到相同计算精度下有同等甚至超过位移有限元的计算效率。针对工程中的复杂杆系结构，利用平衡与协调的对偶性，探讨LIM在复杂平面框架结构中的应用，建立了平面框架结构的LIM基本方程，提出了针对典型支座约束以及组合结点的处理方法。该处理方法的线弹性问题算例表明，与位移有限元相比具有至少同等的精度和相当的计算效率。在支座本身不考虑塑性的情况下，该处理方法同样适用于弹塑性问题，为LIM在复杂杆系结构的弹塑性分析中奠定了基础。     

CALCULATION OF CONTACT PRESSURE UNDER FOUNDATION RESTING ON VISCO-ELASTOPLASTIC SUBGRADE

In this paper, the finite element method(FEM) is carried out for the contact pressure under circular foundation with visco-elastoplastic model and a 8 node finite element program determing parameter. In order to prove the reliability of the theoretical analysis, a circular rigid loading plate test on remolded clay is done. Otherwise, a comparison of the measuring contact pressure under box foundations of highrise buildings in Beijing and Shanghai with the calculated value by different method is made. The result shows the calculated value by the method proposed in this paper is more coincident with practical data.     

A Method Coupling FEM and Singular Solution of Infinite Plane with a Hole for Underground Engineering

In this paper, a simpler and direct coupling method, i.e. finite element method coupled with singular solution of infinite plane with a hole, is proposed for the analysis of underground engineering. The numerical example shows that the elastic effectiveness of the infinite plane outside the artificial boundary upon the inside region is exactly expressed.     

The Taylor series multipole boundary element method (TSM BEM)and its applications in rolling engineering

Rainfall is the main input for probabilistic analysis and prediction of rainfall-triggered landslide. The joint probabilistic structure of daily rainfall (DR) and cumulative rainfall (CR), which are dominant parameters of rainfall related on landslide in Chongqing region, was analyzed. Following the traditional technology, daily rainfall was translated into discrete variable by rainfall grade and cumulative rainfall became continuous variable if records with very small cumulative rainfall were ignored. Then joint probabilistic model of discrete variable and continuous one was derived, and transiting solution of conditional density function was put forward, together with its approximation via a family of Dirac δ sequences. Naturally, the proposed method was used to analyze conditional density function of cumulative rainfall in Chongqing region, and the numerical results were verified by comparison. However, most of the conditional density functions were irregular and not modeled by simple probability density function, thus the finite mixture distribution was introduced, which is of uncomplicated format and relatively high precision. At last, the joint probabilistic model of daily rainfall and cumulative rainfall was built up by combining frequency function of grade of daily rainfall with conditional density model of cumulative rainfall.     

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。     

Complex Variable Function Solution of Stress and Displacement of Surrounding Rock Buried Deep Horseshoe-Shaped Tunnel Excavation

An analytical solution was presented for the stresses and displacements around horseshoe-shaped tunnel using Cauchy integral method and Optimization theory in an elastic half-plane. Since the depth of a tunnel was larger than the size of the tunnel, gravity loads were simplified as uniform normal loads along far-field boundary. Finite element model was used to verify the accuracy of analytical solutions. Comparison between the results of numerical analysis by finite element method and those from the closed solutions indicates that the closed solution is reliable and applicable for the stress and displacement field around horseshoe-shaped tunnel tunnels at great depth.     

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.     

Numerical simulation of the internal dynamic excitation of a spiral bevel gear transmission

A 3-D geometry model and a static/dynamic finite element (FE) model of a spiral bevel gear transmission are established. Using ANSYS software, the mesh stiffness excitation of a tooth pair is calculated via the static contact FE method. Using LS     

Axial Bearing Capacity Design Method of Cold-Formed Steel Quadruple-C Built-up Section Members

The finite element model involving geometric large deformation,materials and contact nonlinearity is established.Specimens of cold-formed steel quadruple-C built-up section members are simulated and the finite element models are proved to be valid.Then,numerical analysis on the behavior of specimens with different slenderness ratio and flange flakiness ratio are carried out,and then the axial bearing capacities of specimens are obtained.Based on effective width method and direct strength method (DSM) in related codes,two design methods of cold-formed steel quadruple-C built-up section members under axial compression are proposed:effective length method and correction factor method.It is shown that:the final failure characteristics of all specimens are local buckling and distortional buckling.In the case of not considering the reduction of effective length,the results calculated by each code are slightly lower than those of test and FEM when the slenderness ratio is less than 50,while the results are too conservative when the slenderness ratio is more than 50.     

Analysis and Design of Stigmata Upsetting Die

Upsetting, a typical hot deformation process, is simulated by using rigid-viscoplastic finite-element method, its instantaneous stress distribution over the interface between the die and workpiece being derived for the finishing upsetting stage. Based on these computations and in conjunction with elastic finite element method,die strength is then analysized. An optimization design for prestressed die inserts is adopted to decrease pressure being applied to the working surface of upsetting die,and in turn,to prolong its service life.     

Numerical Analysis of the Streaming Potential in Bone Tissue

Biphasic porous medium model,based on the mixture theory in continuum mechanics frame,is used to depict the distributing disciplinarian of sclerotin's stress field,distortion field and pore pressure when the bone tissue is subjected to various dynamic loadings.The coupling relationship among the distortion,fluid flow and the streaming potential is studied.The penalty finite element formulation for streaming potential is studied.The penalty finite element formulation for streaming potential distributing in bone tissue is obtained by using Galerkin weighted residual method for the biphasic porous medium model with corresponding initial and boundary conditions,in this modeling,the solid phase is assumed to be isotropic elastic medium,and the fluid phase is ideal fluid.The computational results show that because of the distortion of bone tissue the marrow's flow is raised,then the electriferous partical moves in the porous and the streaming potential appears.     

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.