Elastic - plastic design of unbraced frameworks

A computer program for the optimum elastic-plastic design of two-dimensional steel frameworks is described, and design examples are presented. These examples are used as a basis for comment on some of the assumptions adopted in the program. The paper also compares and contrasts the philosophy used in the program with other approaches reported in the literature.     

Computer aided optimal plastic design

An interactive method for optimal plastic design of structures that obey the square yield criterion is presented. Sections of fixed dimensions such as standard sections can be used for design and realistic cost estimates can be used in assessment. The design is developed interactively by upgrading in steps, using the rate of increase of strength per unit incremental cost as a guide. The entire method is explained by establishing the physical meaning of the expressions derived. The method is suitable for implementation in microcomputers.     

Computer aided EDM electrode design

A large number of EDM electrodes are used in die and mold manufacturing. However, the electrode design is very time consuming. This paper introduces a computer-aided electrode design system for die and mold manufacturing. Using this system, when the electrode boundaries are selected, the electrode tool, its holder, and a work coordinate system are created automatically. An algorithm of sharp corner uncut detection for electrode design is also developed. With this algorithm, sharp corner uncut can be detected by calculating the surface angles at their common edges. The system has been tested and proved to be able to shorten the electrode design lead-time significantly.     

Computer aided design of unit loads

The unit load design problem includes the selection of the best pallet or container size, the best pallet or container layout, and the best number of parta per pallet or container. Three different approaches to solve the unit load design problem are identified in this paper and a new procedure is proposed: Computer Aided Design of Unit Loads (CADUL I). Using CADUL I, unit loads are designed considering system constraints (i.e., rack opening dimensions, aisle width, trailer-truck container dimensions, product crushability constraints, material handling equipment stacking capability and weight capacity) and a cost function that includes handling, storage, transportation, and pallet or container costs. An example is used to illustrate how CADUL I works and how these approaches to unit load design perform sensitivity analysis to validate the results obtained.     

建筑施工模板计算机辅助设计系统

为减少建筑施工模板浪费,加快模板的施工,设计并开发模板计算机辅助设计系统.该软件是基于AutoCAD ObjectARX二次开发的,包括模板的优化配置和支撑设计,采用动态规划算法实现模板的最优布置,对模板支撑提出半刚性节点的计算模式,从模板的设计方案到最后详细的构件模板用量配置图都由计算机进行辅助设计,能够自动给出模板支撑计算书.该软件能实现模板工程中施工的数字化管理,进而规范和优化模板工程设计.     

Computer aided design of the sitting workplace

This paper demonstrates the use of personal micro-computers to individualize the design of the sitting workplace. Engineering static and functional anthropometry as well as ergonomic design principles are implemented. Computer outputs and a case study are presented.     

Computer aided design of post-tensioned concrete reservoirs

A computer method based on the classical shell and plate theories is presented for the elastic analysis of cylindrical water tanks subjected to axisymmetrical loading and post-tensioning loads. A spherical dome or circular plate roof, cylindrical container, top and bottom ring beams together with a circular plate foundation are considered as possible components of a water tank in the flexibility formulation. Classical shell, plate, and ring beam theories are used to obtain flexibility coefficients. A computer program has been developed based on this formulation and successfully used in the design of post-tensioned concrete water tanks with diameters of 80 m built in Saudi Arabia.     

Computer aided design of database internal schema

A large number of complexly interrelated parameters are involved at the internal schema level design of database systems. Consequently, a single design model is seen to be infeasible. A package of three aids is proposed to assist a designer in step by step design of internal schema. The three aids pertain to splitting of a relation, merging of relations, and access strategy selection for a relation.     

Computer aided design of aircraft electrical systems

The CAESAR interactive computer graphics system for the design, analysis and production of aircraft electrical circuitry is described. The system is built up of several independent design, analysis and drafting modules which may be interactively interfaced in conjunction with an on-line master data base. Preliminary cost-effectiveness predictions at IAI have shown that implementation of the total system in a production environment will introduce greater design efficiency relative to conventional methods, in addition to significant savings in time, effort and cost.     

Computer aided minimum weight design using BEM

A mathematical programming technique and the boundary element method are combined to create the optimized shape of machine elements and structural components subjected to static external loads. The structural stress/deformation analysis and sensitivity analysis can be performed more correctly and elegantly by boundary discretization alone. The optimizer employed here is the so-called “method of inscribed hypersphere” which is known to be fitted for the object and constraint functions with weak nonlinearity. Minimum weight design of two-dimensional elastic structures is considered under the prescribed constraint conditions. Some numerical results demonstrate the validity of the proposed computational system even for the problem with the restriction expressed by an inequality.     

Computer aided design of prestressed concrete highway bridges

The paper presents a computer aided design system for prestressed concrete highway bridges which, starting from few geometrical data, provides the complete geometry, prestressing steel, reinforcing steel, amount of materials and cost of all the bridge elements: deck, bearings, piers, abutments and foundations. Different configurations are devised, from short and medium to long-span bridges, accounting for different deck super-structures and erection methods. All the results are displayed on the computer screen and can be printed. The system provides also DXF files containing the general layout, cross-sections and prestressing arrangement of box girder bridges. This system allows, in a short time, an accurate design and an economical estimation of a particular bridge, taking into account the most important technical requirements. It is a useful decision-making tool for both design and administration engineers.     

Computer aided design of a three-dimensional steel frame

This paper describes the sequence of events leading to the successful construction of a three dimensional welded and bolted steel frame which formed the structural support for the floors and roof of a church in Mt. Washington, Ohio. The structure was conceived, planned, designed and checked using the concept of computer aided design by means of ICES-STRUDL. The paper illustrates analysis, design, construction and shows the completed structure. The architectural concept was based on the structural system. Itwas conceived jointly by the architect and the structural engineer as a working team prior to the job competition.The preliminary design and its necessary analysis was performed during this conceptual stage at which time it was determined that the proposed system was feasible with respectto aesthetics, with respect to construction and costs, as well as with respect to being capable of proper analysis and design. The final design was then accomplished by both planar frame assumptions and space frame assumptions, where proper releases were employed in both analyses to account for the designer's best estimation of the actual behavior of the physical joints and connections. This was handled by ICES STRUDL-I on the IBM 360/365 digital computer using the capabilities of loading combinations, joint releases, section properties, deformation values, etc. The lack of accuracy of such an elastic and linear structural computer package is also briefly documented. It is relevant with respect to the actual connections in field construction. The framed structure was actually controlled by deflection criteria, although said criteria was not actually provided by the specifications per se, but rather by the psychological aspects of observable sway. Since this was a highly indeterminate and complex space frame, the interaction of member properties, joint framing, analysis, member checks with respect to specifications, and deformation could only have been successfully satisfied by means of a computer aided process.The main theme is the use of computer-aided design techniques in the planning stage and the preliminary design stage, where it was mandatory to determine the general feasibility of the overall system so that the architectural presentation could be accurately portrayed. An above normal degree of accuracy was also essential in the final design checks and thus a computer oreinted design process was essential to the successful execution of this type of structural system and its integration a priori into the architectural system.     

Computer aided tools of ergonomics and system design

Anthropometric digital human models are well established and used in order to get a better design of human‐adapted machines. By the application of electronics and computer operated machines, nearly arbitrary design of controlling and operating the technical equipment seems possible. So more and more the question arises: What is operable by the human operator and what leads probably to a disaster due to much stress. By applying systems ergonomic rules, this can be avoided to a far extent. In order to consider these rules already in an early state of development, it seems useful to incorporate such rules in digital human models. By this procedure, cognitive human models will be created. The combination of such models with anthropometric digital human models will lead to the possibility to carry out virtual experiments under the condition of computer aided design. So, in the future, more ergonomic knowledge will be considered by this new technique. © 2002 Wiley Periodicals, Inc.     

Computer aided design of regulators using multiobjective optimization

The problem of designing linear regulators subject to quadratic cost functions is addressed using multiobjective optimization. Instead of representing conflicting performance measures in a scalar objective function, these measures are treated individually in an attempt to simultaneously optimize the objectives. Although there is no unique solution the approach offers the designer the opportunity of investigating trade-offs in a systematic way. A software package, based on the goal attainment method, is presented and applied to design examples.     

城市道路交叉口计算机辅助设计系统

为提高平面交叉路口的通行能力,基于中国城市道路交通设计理论与方法,运用软件工程的思想完成城市道路交叉口计算机辅助设计系统的设计与实现.系统的数据结构设计合理,能为未来交通控制方案的生成和仿真评价软件的开发提供接口.应用实例表明该系统内核模型符合我国道路交通的实际情况,能大大提高道路平面交叉口设计的效率.     

Computer aided design of form rolls for NC manufacture

Computer aided design (CAD) and computer aided manufacture (CAM) are two modern areas of computer application which have decisive influence in the manufacturing industries. The recognition of the potential of CAD/CAM is worldwide and many have taken advantage of the new technology. The design and manufacture of form rolls and the special tooling used in cold roll forming of thin walled metal sections are areas where the CAD/CAM approach can make a positive computer aided tool for creating form roll designs suitable for NC (numerical control) manufacturing. This work was undertaken by the Department of Production Technology and Production Management at the University of Aston in Birmingham in collaboration with a leading manufacturer of thin walled sections. Significant improvement of lead time and productivity in both design and manufacturing of form rolls have been accompanied.     

Computer aided fixture design: Recent research and trends

Widely used in manufacturing, fixtures have a direct impact upon product manufacturing quality, productivity and cost, so much attention has already been paid to the research of computer aided fixture design (CAFD) and many achievements in this field have been reported.In this paper, a literature survey of computer aided fixture design and automation over the past decade is proposed. First, an introduction is given on the fixture applications in industry. Then, significant works done in the CAFD field, including their approaches, requirements and working principles are discussed. Finally, some prospective research trends are also discussed.     

Computer aided control system design applied to milk drying plants

This paper reviews a computer aided control system design facility that has been used to develop a set of control systems that have been implemented on a pilot scale industrial process. The facility caters for a broad range of control situations including those with interactions, time delays and disturbances. Online interactive graphics is used as a design aid for the identification of plant dynamics and for the assessment of control system performance. Control systems may be developed systematically to be structured in a hierarchical configuration on the plant. Particular applications to the plant, an evaporator and a spray drier, are discussed in detail.