AN IMPROVED MIXED FINITE ELEMENT METHOD OF ANALYZING THREE-DIMENSIONAL ELASTIC CONTACT PROBLEMS

This paper presents an improved mixed finite element method of analyzing elastic contact problems, in which a new numerical algorithm is developed to calculate the flexibility matrix of the contact region. With this method the contact problem of two teeth-engaging is initially solved as a three-dimensional elastic finite element analgsis, In comparison with mixed fimte element method, the improved mixed finite element method is much more efficiency in solving contact problems.     

The Analysis of Bending Deformation of Cutter Tooth and Gear Tooth During Shaving Process

In this paper,the variation pattern of the contact point on cutter tooth and gear tooth is analyzed during gear shaving process. According to the shaving force measured by dynamometer, the deformation of cutter tooth and gear tooth at the contact point is calculated by appying the three dimension finite element method. The deformation curve of cutter tooth and gear tooth are obtained by analying deformation in shaving domain. It is the basis of studying relation between shaved amount and deformation.     

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.     

施工阶段大跨径预应力混凝土刚构桥腹板开裂机理

进行了大跨径预应力混凝土刚构桥腹板开裂机理研究,基于弹性力学平面问题分析方法,推导了集中荷载作用下的板件应力函数表达式,绘制了不同受压边长与集中荷载长度比（d/a）下的横向应力曲线,拟合了集中荷载作用下构件的横向应力求解函数,构造了混凝土刚构桥腹板在预应力集中荷载作用下等效压力矩形的选取方法,并基于平面应力的表达式提出了在三维情况下沿预应力轴线的横向应力计算方法。通过建立某预应力混凝土刚构桥0~3#段实体有限元模型,分析施工过程中刚构桥混凝土腹板在不同等级预应力作用下的开裂情况。结果显示：有限元裂缝模拟与实桥腹板开裂范围一致,有限元应力分析结果下限值与推导的横向应力求解函数计算结果接近,变化趋势一致,印证了横向应力函数求解方法的正确性。     

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.     

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.     

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.     

砂土地基上圆形浅基础三维破坏包络面的理论研究

对砂土地基上圆形浅基础在竖向荷载V、水平荷载H及力矩M复合加载条件下的承载力进行了系统的三维有限元分析。在分析中,砂土假定为纯摩擦材料,遵循基于Mohr-Coulomb破坏准则的理想弹塑性本构关系。首先,对圆形浅基础的竖向承载力进行了有限元计算, 并与滑移线解法进行了对比,两种方法所得结果比较吻合。进而探讨了砂土内摩擦角对于基础在V-H、V-M荷载平面与V-H-M三维荷载空间内的破坏包络轨迹的影响。计算结果表明,与不排水情况下软黏土地基上基础破坏包络面相比,砂土地基上圆形浅基础的破坏包络面形状有较大差异, 但V-H和V-M平面内的破坏包络面形状仍具有较好的归一化特性。基于有限元计算结果,建立了圆形浅基础在V-H-M三维荷载空间内的破坏包络面方程, 该方程可用来合理评价复合加载条件下砂土地基上圆形浅基础的整体稳定性。     

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.     

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.     

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.     

Study on the Nonlinear Vibration System with Slow-changing Parameters

In this paper a posteriori error estimates for Galerkin approximation of general operator equations is firstly presented in the framework of Sobolev spaces. Then a practical posteriori error estimates formula for the adaptive boundary element method solving the acoustic scattering problem with a finite plane screen is obtained by triangulations. The mathematical model of this problem is the three dimensional Neumann boundary value problem of Helmholtz equation with finite plane boundary.     

Model Analysis of Tower Crane Structure Based on ANSYS

In this paper,a complete dynamic model of the tower crane is set up by the finite element software ANSYS and then the QTZ25 tower crane model is calculated.Through comparing the results,the feasibility of this method is proven.This method is a new approach to fast and precise analysis on dynamical model of tower crane structure.     

Numerical simulation of dynamic response and radiation noise of gearbox

Considering the internal dynamic excitation produced by stiffness excitation, error excitation and mesh impact excitation, a dynamic finite element model of transmission system and structure system of gearbox is established. The normal mode and the dynamic responses of gearbox under the internal dynamic excitation are calculated by using the numerical simulation software ANSYS. Based on the result of dynamic responses, the boundary excitation condition is determined, and then the acoustic boundary element model is built. With the software of SYSNOISE, the surface acoustic pressure of gearbox and the radiation noise of field points are solved by the direct boundary element method. The test of airborne noise is carried out. The computational results obtained are in a good agreement with the data of experimental test.     

The Finite Element Simulation of Pipe Bend Forming

A dynamic explicit finite element method is used to pipe bend forming processes on bender in this paper.The degenerated shell element and co-rotational coordinate system are employed.The material of pipe is assumed to satisfy Hill's anisotropic elasto-plastic yield condition.The bend die and press die are assumed as rigid surfaces and the contact force is computed by penalty method.Several numerical examples are given.They show that this method is effective.     

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     

The Finite Element Computation of Stress on Type Surfaces of Three Bioprostheseis Valves

In this paper the static stress distribution of closed valve during diastole under the peak across valve pressure difference is analyzed with nonlinear finite element method. We analyzed the three shapes i. e.,spherical,cylindrical and rotating paraboloid type valves, respectively as a result of computation, it is suggested that the maximum principal normal and shearing stress for rotating paraboloid type valve are smaller than those for the cylindrical and spherical type valves. It shows that there exist some similarities of the stress distribution among these three type valves.     

THE APPLICATION OF MULTIBODY DISCRETE METHOD IN RING''S VIBRATION ANALYSIS

A ring's muJtibody discrete model is discussed in this paper. The ring's plane geometric nonlinear vibration equations are derived. Compared with the finite element and lump mass methods, this method is better. In the last pa it of the paper, the eigenvalues, the first 9 modes of the ring, the geometric nonlinear dynamic responses of the ring are calculated.     

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.     

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.