Computer-Aided Design Using Object-Oriented Programming Paradigm and Blackboard Architecture

Abstract: Object-oriented programming characteristics of abstraction, inheritance, and encapsulation of data and operations support three desirable features in the development of complicated engineering software systems: modularity, reusability, and ease of maintenance. This paper presents computer-aided design (CAD) of structures using the object-oriented programming paradigm and a blackboard architecture for management of input/output data as well as intermediate data created during a consultation with the CAD system.     

预应力钢桁架优化设计

预应力钢桁架优化设计不仅包括钢桁架杆件截面优化,还包括布索方案和预拉力值的优化。本文以造价作为目标函数,通过对一个预应力钢桁架工程实例的优化设计,取得了显著的经济效益,说明了优化设计研究在工程设计中的重要意义。     

人字形折式钢屋架的设计与施工

本文介绍了一种新型的空间结构人字形折式钢屋架,结合实际工程,叙述了这种结构的设计、简化计算方法、构造特点及施工方法。它具有较好的承载能力,空间刚度大,经济指标好,适用于一些坡屋顶的生产厂房和仓库的轻型屋盖。     

矩形钢管混凝土桁架设计

根据国内外矩形钢管和矩形钢管混凝土结构规范、规程和有关研究成果 ,提出了矩形钢管混凝土桁架设计的构造要求、桁架杆件和节点设计与计算方法 ,可供工程技术人员设计时参考 ,并为我国《矩形钢管混凝土结构技术规程》的编制提供了参考依据     

A Knowledge-based Expert System for Design of Roof Trusses

Aknowledge-based expert system has been developed for design of roof trusses, called RTEXPERT. RTEXPERT can advise the user on the appropriate type of the roof truss, selection of the layout of the truss (such as the pitch of the truss and number of panels), and the loading. The basis of design is the American Institute of Steel Construction (AISC) specification. The truss is designed for dead, live, snow, and wind loads in accordance with the American National Standard Institute (ANSI) specification. A novel part of RTEXPERT is the automatic computation of nodal forces due to various loads. The user needs to indicate only the types of the materials used as roof covering and the location of the structure in the United States. RTEXPERT automatically generates all the nodal forces. The knowledge base and explanation facility of RTEXPERT have been developed using INSIGHT 2 + expert system shell. The mathematical computations, graphic algorithms, and data file manipulation routines have been developed in Turbo Pascal. RTEXPERT has a comprehensive graphic interface for displaying the truss configuration, cross sections, loading, and deformed shape. Information about individual members is presented through multi-window graphicstext displays. RTEXPERT can be used as an "intelligent assistant" for design of roof trusses.     

计算机辅助设计深基坑支护体系

在有限元分析的基础上,采用多步分析方法,应用DESSⅡ系统软件实现计算机辅助设计深基坑支护体系。     

A Microcomputer Interactive Graphics Software for Design of Steel Trusses

Current advances in microcomputer technology provide the tools to use interactive graphics in the development of efficient computer programs. The use of computer graphics facilitates the definition of complicated engineering models, and permits a clear display of the results. In this paper, an educational microcomputer software package, TRUSS-AD, is described to demonstrate the effectiveness of applying interactive computer graphics in solving structural engineering design problems. TRUSS-AD allows the user to: (1) define a truss geometry and loading conditions graphically; (2) analyze and design the truss in an interactive mode; and (3) display all results in a concise and clear graphical representation. The stiffness method is used in the analysis process. The design can be performed by using either the "Load and Resistance Factor Design" or the "Allowable Stress Design" methods. The software is written using the basic language for IBM or compatible personal computers.     

某大跨转换桁架高层钢结构设计

阐述了上海某大跨转换桁架高层钢结构设计思路。根据该工程的体型特点,对比了多种不同的转换结构方案,综合考虑各种因素最终选择"下托式"的主、次桁架转换方案。计算结果表明,采用该方案的结构整体指标满足规范要求,具有足够的抗侧刚度。在转换桁架设计中考虑了次框架的空腹桁架效应、活荷载不利布置和抗连续倒塌等因素影响;对转换层的楼板应力及转换桁架钢结构关键节点进行了有限元分析,并提出了相应的加强措施;通过施工模拟分析评估了施工顺序对整体结构的影响。该项目的设计过程及方法可为类似项目提供参考。     

分布荷载作用下桁架的有效整体设计方法

适当考虑加载区域,对分布荷载作用下桁架的半确定性拓扑及几何学设计的一种有效方法进行介绍。受荷节点不能看作基本节点处理,这些节点的数量和位置作为设计变量来考虑。这些量对桁架及其分布的荷载区域均有影响。在介绍一种新的参数指标的基础上,提出分布荷载作用下桁架的整体设计方法,这一参数可以作为桁架设计中的附加设计目标或约束,它也可以很好地替代半确定性整体设计中的加载域目标。通过一个研究实例验证了该设计方法的有效性。     

浅议计算机辅助太阳能光伏建筑一体化设计方法*

光伏建筑一体化（BIPV)指光伏组件集成于建筑,BAPV指光伏组件附着于建筑。两种类型相比BAPV出现早,是较为传统的光伏建筑。BAPV的设计侧重于光伏系统设计,无法满足光伏建筑一体化的设计要求。探讨了利用Ecotect和PVsyst软件辅助光伏建筑一体化设计的内容和方法,主要分为基础资料收集、规划和场地设计、光伏建筑一体化的方案设计、光伏组件的构造、系统设计及相关专业设计5个阶段。前3个阶段由建筑师完成,第四个阶段由建筑师和电气工程师完成,最后一个阶段由相关专业的工程师完成。     

Computer-Aided Design of Prestressed Concrete Cellular Bridge Decks

Abstract: This paper illustrates the application of an effective optimization procedure for the design of prestressed concrete cellular bridge decks consisting of single- and two-cell box girders or voided slab systems. An approximate live load moment analysis using the finite-strip method and finite-difference techniques that determines moment sensitivities to changes in the deck depth and flange thickness is proposed for box girder decks. The optimization process is much simplified by eliminating the need of finite-strip reanalysis at each iteration. The optimal design is formulated as a nonlinear programming problem and solved by the projected lagrangian method. The resulting solutions may be used as preliminary designs for short- and medium-span highway bridges, for which cellular decks represent competitive solutions. Optimization results show that voided slab decks are more economical than box girder decks for the short span range and wide decks, and single-cell box girders are a cost-effective alternative for medium span range and narrow decks.     

新中国国际展览中心预应力立体管桁架屋盖结构设计

新中国国际展览中心工程属2008奥运配套工程。一期工程为8个主展馆,各展馆平面均为71m×172m的矩形,分别由10榀倒三角形预应力立体管桁架构成屋盖体系,桁架跨度为70.2m。桁架下弦为方钢管,其余杆件均为圆钢管,预应力索穿于下弦杆内,支座采用铸钢单向铰支座。结合具体结构设计,进行了屋盖结构静力性能分析、单榀桁架出平面稳定验算、屋盖中震弹性验算、结构在罕遇地震作用下的弹塑性变形验算,并进行了单榀桁架断索及单榀桁架失效等极端工况下屋盖体系的抗连续倒塌验算。研究结果表明,结构各项性能均满足规范要求,并具有良好的静、动力受力性能。     

Collaborative Design: Combining Computer-Aided Geometry Design and Building Information Modelling

The spatial expression and ordering of social processes is one of the primary aims of architecture. Such is the view of Zaha Hadid Architects (ZHA), where Shajay Bhooshan heads the computation and design group (CoDe). Here he explains how the practice has followed in the footsteps of the automotive, aircraft and shipbuilding industries in adopting a hybrid approach to design development. As demonstrated by a mathematics-themed gallery conceived by ZHA for London's Science Museum, it assimilates historical knowledge while facilitating fabrication and allowing for future flexibility.     

钢桁架屋盖结构抗火设计实用方法

钢桁架结构作为大空间建筑屋盖结构常用的形式之一,其火灾下的承载能力对于保证大空间建筑屋盖结构在规定耐火极限内的安全性至关重要。采用有限元数值分析方法和结构力学理论分析,对桁架屋盖在多参数影响下的抗火性能进行了研究,发现平面外支座约束条件、火源位置及结构荷载比是影响钢桁架结构抗火承载力的关键因素;桁架屋盖体系中的支撑构件在火灾下失效会使桁架平面外支座约束方式产生变化,从而影响上弦杆件平面外抗火承载力;基于整体结构受火性能,提出了钢桁架屋盖抗火设计实用方法,该方法有助于明确临界温度法或承载力法中相关参量的取值,为基于计算评价桁架屋盖结构在大空间建筑火灾下的抗火性能提供科学的依据。     

Computer-Aided Architectural Design Oriented to Robotized Facade Panels Manufacturing

This article presents a manufacturing system of prefabricated panels for the construction industry that has been developed for the Spanish company Dragados, S.A. The main contribution of the system is the automatic manufacturing programming, taking into account process restrictions and using as input the architect's three-dimensional (3D) drawing of the building done on a computer-aided design (CAD) system. From the CAD building design, the optimal facade to panel partition is obtained. In order to manufacture each panel, based on CAD information, automatic task and path planning are performed for the equipment present in the robotized flexible manufacturing cell.     

A Graphics Preprocessor for Computer-Aided Design and Drafting of frame Structures

An interactive microcomputer-based graphics preprocessor has been developed for computer-aided design and drafting of plane frame structures. The graphics preprocessor has been developed in Advanced BASIC version 3.0 on an IBM Personal Computer. The preprocessor allows various manipulations of the frame structure such as zooming, panning, shrinking, expanding, node labeling, and element labeling. The flow between the graphics display and the data input is very easy and allows the user to enter new frame data, visually check it, and edit the data quickly.     

计算机三维造型设计教学方法初探

计算机三维造型设计是重要的现代设计方法之一,笔者在长期教学实践过程中,结合电脑教学的特点,就三维造型设计与艺术教育的相互关系进行了初步探索,旨在对计算机三维造型设计教学实践有一定的实际意义。     

The Automated Underground: Computer-Aided Design of Boston's Central Artery Project

Computer applications related to under-ground construction are described as they are being applied to Boston's Central Artery/Third Harbor Tunnel Project. The project is currently one of the largest highway projects in the country. Computer applications include a geotechnical boring log management system, spreadsheets for tunnel analysis and design, finite-element studies of soil-structure interaction for a construction excavation problem, and software that draws flow nets. Each application is outlined, and problems and future improvements to the methods are discussed.     

T形钢桁架连接节点分析

本文主要介绍T形钢桁架的特点,指出分析桁架节点的意义,对规范中没有提出计算方法的此类连接节点进行分析。重点对T形钢桁架的上弦节点进行探讨,提出了一种节点的简化模型计算方法,采用ANSYS软件进行有限元分析,通过节点的mises应力云图和位移变形图,了解节点在不同荷载作用下的应力分布规律,找出节点受力中最不利的环节,分析节点的受力特性,提出了相应的解决办法,特别是节点设计中的一些构造措施,可以为设计人员在节点设计时提供一些参考。     

Optimal Layout of Bridge Trusses by Genetic Algorithms

In this paper we present an approach to the layout and shape-optimization problem of bridge truss structures using genetic algorithms. The objective is to find an optimal layout design that will have minimum weight or material volume, subject to performance constraints related to member stresses, joint displacements, and member buckling. An automated two-stage optimization search process, which integrates structural analysis by finite-element method, genetic algorithms, and cognitive topology patterns (domain knowledge), is developed to solve the optimal problem. Two examples concerning bridge truss structure are investigated to demonstrate the effectiveness of the proposed method in solving these layout-optimization problems.