多工况下杆系结构拓扑型优化设计

 给出了一种用于杆系结构的拓扑型结构综合算法. 该算法由拓扑 级和形状级两部分组成，并用修正Goldfarb法进行求解. 本文提出的 修正Goldfarb法是根据杆系结构特点吸取文[1]的松弛方法在共轭梯度 法基础上给出的，通过对结构优化算例的计算，说明该方法效果较好.     

空间静不定桁架的变形协调条件及求解

根据桁架受载后各杆件的伸长量、各杆件夹角的变化之间的几何关系，以各杆的伸长量和夹角的微小变化为未知量，建立了空间静不定桁架的变形协调条件，并结合实例给出了求解空间静不定桁架的一种计算方法．     

Post-buckling behavior of a fixed arch for variable geometry structures

The behavior of a bistable strut for variable geometry structures was investigated in this paper. A fixed shallow arch subjected to a central concentrated load was used to study the equilibrium path of the bistable strut. Based on a nonlinear strain–displacement relationship, the critical loads for both the symmetric snap-through and asymmetric bifurcation buckling modes were obtained. Moreover, the principal of virtual work was also used to establish the post-buckling differential equilibrium equations of the arch in the horizontal and vertical directions. Therefore, the whole mechanical behavior before and after the buckling of fixed arches is investigated.     

Topology optimization of multi-purpose structures

Whilst most of the literature on topology optimization of structures deals with so-called selfadjoint problems involving highly idealized, single-purpose structures, this paper discusses topology optimization of multi-purpose structures which concerns nonselfadjoint problems. General methods based on the so-called layout theory, application to trusses and perforated plates and computational difficulties are discussed.     

可视化杆系结构分析程序设计

利用可视化编程语言将杆系优化计算封装为动态连接库 (DLL) ,采用面向对象的方法描述了杆系结构分析所需的类 ,并用数据库技术和三维图形模式对杆系结构分析进行格式化输入输出。通过对杆系结构的特点分析 ,将程序分为三个主要的设计模块 :显示模块、数据管理模块和结构分析模块 ,实现了程序的模块化设计。通过对实例的测试 ,说明该程序已达到对一般多工况杆系可视化设计的目的     

环状折线桁架体育场挑篷结构的性能研究

根据大型体育场的特点和要求,提出一种新型体育场挑篷结构形式.该结构由相邻两榀桁架上下错动而成.分析其固有频率和温度内力分布,表明该结构整体刚度大,温度内力较小,可充分发挥材料的强度.对桁架的榀数、厚度及高差进行参数分析,计算比较用钢量、刚度,验证其具有较大的平面外刚度,并给出合理的设计参数.分析在地震作用下结构内力的分布,说明该结构具有良好的抗震性能.与国家体育场比较,证明该新型结构经济性好,是一种优良的结构形式.     

予应力钢桁架刚度反演分析的摄动迭代法

基于文（１）所建立的拉索式予应力钢桁架基本计算,根据矩阵摄动原理进一步给出了以竖向为位移为约束反演确定任意布索张拉予应力钢桁架单元刚度和的索刚度的摄动迭代公式。算例表明,该方法具有较高的精度,可满足工程设计需要。     

A simple analytic method for computing the natural frequencies and mode shapes of tall buildings

A simple, yet accurate analytical approach based on energy principles is developed for quick computation of natural frequencies and mode shapes of multistory buildings constructed using framed tube, shear core and double belt trusses systems. The approach here is based on development of a continuum model that would be equivalent, in major motions, to the actual multistory building. Models studied here are cantilever beams with concentrated moments placed at belt truss locations. Governing equation and boundary conditions of the equivalent beam and moment system were derived using the energy method and Hamilton’s principle. Separation of variables technique is then applied to model’s partial differential equation to obtain the required eigensystem. Robustness and correctness of the proposed method are demonstrated through several numerical examples. Here, 40, 55 and 70-storey tall buildings with combined system of framed tube, shear core and double belt trusses, in which the results obtained from the proposed method, are compared with those obtained from three-dimensional analyses using SAP2000 software. Comparative analyses reveal that the proposed method is simple and efficient; and it provides reasonably accurate results quickly, a feature that is vital during the early stages of building design.     

Non-linear analysis of structures using two-point method

Non-linear algebraic equations must be solved by an iterative method, the non-linear equations being linearized by evaluating the non-linear terms with the known solution from the preceding iteration. The Newton-Raphson method, which is based on the Taylor series expansion and uses the tangent stiffness matrix, has been extensively used to solve non-linear problems. In this paper, a new Newton-Raphson algorithm is developed for analyses involving non-linear behavior. Our method, here named as a two-point method, is constructed as a predictor-corrector one, most frequently taking Newton's method in the first iteration. It should be noted that our concern in this research ignores the problem of passing limit points. The presented method incorporates the known information at each stage of the loading process to determine the subsequent unknown variables. Compared with the classic Newton-Raphson algorithm, it offers a strategy that can be deployed to reduce both the number of the iterations and the computing time involved in non-linear analysis of structures.     

On the solution of a nonlinear programming problem by decomposition

A decomposition method, used in least-weight plastic design, is extended to solve problems with nonlinearity arising from variable structure geometry. The problem considered is that of finding vectorsx ₁,x ₂, andq that minimize [l max{|x ₁|, |x ₂|}], subject toAx ₁=b ₁ andAx ₂=b ₂, where both the vectorl and the matrixA are nonlinear functions ofq.