WSP特殊螺纹接头油井管的研制

介绍了WSP特殊螺纹接头的基本结构和设计思想,运用有限元方法,重点论述了密封设计和连接强度设计的方法和准则,并通过全尺寸试验进行了验证。计算和试验结果表明,该接头具有先进的螺纹形式、合理的扭矩台肩和金属/金属密封结构,有效地克服了API圆螺纹和偏梯形螺纹的不足,螺纹达到了与管体等强度,气密封能力达到了管体的内壁屈服压力。研究结果可以为开发更多适合油气田实际的特殊螺纹接头油井管提供参考。     

Mixed formulation of nonlinear beam on foundation elements

This paper presents an inelastic element for the analysis of beams on foundations. The element is derived from a two-field mixed formulation with independent approximation of forces and displacements. The state determination algorithm for the implementation of the element in a general purpose nonlinear finite element analysis program is presented and its stability characteristics are discussed. Numerical studies are performed to compare the model with the classical displacement formulation. The studies confirm the superiority of the proposed model in describing the inelastic behavior of beams on foundations.     

Exact integration in the boundary element method for two-dimensional elastostatic problems

This paper derives the exact integrations for the integrals in the boundary element analysis of two-dimensional elastostatics. For facilitation, the derivation is based on the simple forms of the fundamental functions by taking constant, discontinuous linear and discontinuous quadratic elements as examples. The efficiency and accuracy of the derived exact integrations are verified against five benchmark problems; the results indicate that the derived exact integrations significantly reduces the CPU time for forming the matrices of the boundary element analysis and solving the internal displacements.     

金属包覆平板波导模式特性的有限元法分析

采用有限元法（FEM）分析了具有复数折射率的金属包覆介质波导的模折射率与模场分布情况。计算了具有损耗层的6层介质平板波导模折射率，并与解析解比较，二者有较好的一致性；分析了金属包覆3层平板波导中TM模折射率与波导芯厚度的变化关系，计算了金属包覆5层平板波导中TM模折秧经与金属层厚度的变化关系，并结合对模场分布的分析对模式进行了定性判断，给出了其模式演变过程。     

Boundary knot method for 2D and 3D Helmholtz and convection–diffusion problems under complicated geometry

The boundary knot method (BKM) of very recent origin is an inherently meshless, integration‐free, boundary‐type, radial basis function collocation technique for the numerical discretization of general partial differential equation systems. Unlike the method of fundamental solutions, the use of non‐singular general solution in the BKM avoids the unnecessary requirement of constructing a controversial artificial boundary outside the physical domain. The purpose of this paper is to extend the BKM to solve 2D Helmholtz and convection–diffusion problems under rather complicated irregular geometry. The method is also first applied to 3D problems. Numerical experiments validate that the BKM can produce highly accurate solutions using a relatively small number of knots. For inhomogeneous cases, some inner knots are found necessary to guarantee accuracy and stability. The stability and convergence of the BKM are numerically illustrated and the completeness issue is also discussed. Copyright © 2003 John Wiley & Sons, Ltd.     

Solution of large deformation contact problems with friction between Blatz-Ko hyperelastic bodies

The present paper is devoted to the analysis of the contact problems with Coulomb friction and large deformation between two hyperelastic bodies. One approach to separate the material nonlinearity and contact nonlinearity is presented. The total Lagrangian formulation is adopted to describe the geometrically nonlinear behavior. Nondifferentiable contact potentials are regularized by means of the augmented Lagrangian method. Numerical examples are carried out in two cases: rigid-deformable contact and deformable-deformable contact with large slips. The numerical results prove that the proposed approach is robust and efficient concerning numerical stability.     

钢筋砼框架非线性分析的简化单元模式

介绍一种用于钢筋混凝土框架二阶弹塑性分析的简化单元模式。它考虑了轴力的二阶效应、横截面的塑化和塑性区长度等非线性因素的影响。利用杆件截面的弯矩—曲率关系,可以直接由弹性杆件的转角—位移方程建立单元的非线性刚度矩阵。经与试验结果比较,说明计算结果是正确的。     

腐蚀算法在重建一类特殊管道中的应用

针对一类特殊而不能直接对其观察的管道（如动物的血管），为了准确了解其内部特征和形态，借助计算机给出了一种用腐蚀算法来重建管道原形的方法。这种方法简单易行，而且精确度高。     

主动约束层阻尼板结构动力学建模研究

将有限元法和GHM法相结合，给出了建立主动约束层阻尼（ACLD）板结构动力学模型的新方法。建模时，考虑到粘弹材料（VEM）的纵向位移影响，采用GHM方法描述VEM的本构关系，解决了VEM的力学特性随温度和频率变化的难点，避免因VEM的复杂本构关系而产生的微分积分方程。算例表明本文给出的建模方法是准确的，ACLD结构能够有效控制结构振动。     

Finite elements in the analysis of pressure vessels and piping-a bibliography (1976–1996)

The paper gives a bibliographical review of the finite element methods (FEMs) applied for the analysis of pressure vessel structures/components and piping from the theoretical as well as practical points of view. The range of applications of FEMs in this area is wide and cannot be presented in a single paper; therefore the aim of this review is to give the reader an encyclopaedic view of the differnt possibilities that exist today for the finite element analysis in the fields of pressure vessels and piping. The bibliography at the end of the paper contains approximately 1900 references to papers, conference proceedings and theses/dissertations on the subject that were published in 1976–1996. These are classified in the following categories: linear and non-linear, static and dynamic, stress and deflection analysis; stability problems; thermal problems; fracture mechanics problems; contact problems; fluid-structure interaction problems; manufacturing of pipes and tubes; welded pipes and pressure vessel components; development of special finite elements for pressure vessels and pipes; finite element software; and other topics. Also finite element software, general purpose and special purpose codes, used for the analysis of pressure vessels and pipes are briefly discussed and presented.