摘要:

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

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1987.tb00145.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Groundwater quality and quantity modeling in regional aquifer systems has developed very rapidly within the last twenty years. The new computational methods introduced to this field offer flexible tools to practicing engineers to analyze complex problems that otherwise would have been unfeasible to solve. Recent advances made in microcomputer technology introduce a new phase to this progress since such computational facilities are now readily available to most engineers, and the existing groundwater models can be implemented on these computers for efficient and reliable simulation. The study summarized here is an extension of an earlier steady‐state groundwater Now model developed by the first author. The numerical model discussed here is developed for an IBM‐AT or compatible system with 640K core memory capacity. The FORTRAN code is compiled using the Microsoft version 3.2 FORTUNE Compiler (MS‐FORTRAN Compiler) which runs under version 1.25 of the Microsoft Disk Operating System (MS‐DOS). For fast numeric processing an 8087 coprocessing environment is suggested but such a processor is not necessary for proper execution. The unsteady multilayer aquifer model developed here is verified based on analytical solutions for multilayer aquifers available in the literature. The computer code generated is identified as MUCF1 (Multilayer‐Unsteady‐Groundwater

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1987.tb00146.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Ageotechnical engineering microcomputer program has been developed for the determination of permanent slope displacements resulting from earthquake shaking. The Newmark procedure, in which accelerations in excess of yield accelerations are double integrated to obtain displacements, has been incorporated into the program DISPLMT. Several user options are available for describing the yield acceleration function, including variation with time and variation with displacement. Screen graphics are available which allow the user to observe the down slope movements of the Newmark sliding block as they increase with time during the simulated earthquake. DISPLMT has been used to calculate the permanent movements of an earth dam using acceleration‐time histories and soil shear stresses determined from a separate analysis. Modification to the conventional Newmark procedure, by introduction of a “slip layer,” has been made in the analysis of a dam. Permanent slope displacements can be analyzed using the recommended procedure, which involves fairly simple computations that can be performed in a reasonable period of time with the exclusive use of microcomp

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1987.tb00147.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

The BASIC language, available on almost all personal computers in interpreter form, has a number of strengths and some major weaknesses. It is a powerful language in its ability to read to and from the monitor screen, to manipulate strings, and to perform simple graphics. It is a weak language for use in computationally intensive programming, and, in the form usually provided with microcomputers, cannot access the math coprocessor. The FORTRAN language is good for working with large arrays and for performing extensive computations with high precision numbers, but is weak in the areas where BASIC is strong.A typical engineering program consists of three phases, data input, computation, and data output. The user of a microcomputer program expects to be offered easy interactive data entry and correction, fast computation, graphical review of results where applicable, and foolproof program operation including graceful recovery from errors accompanied by meaningful error messages. Satisfying these desires can be accomplished by the programmer who properly meshes the complementary strengths of BASIC and FORTRAN. This paper describes how to write an engineering program package which uses BASIC in accomplishing data input through data‐entry screens, FORTRAN in the number crunching phase, and BASIC in the post‐processing graphical display phase. Associated problems of formatting files for use by both BASIC and FORTRAN programs, entry of default values during initial data input or data change, and data base management are discussed.The BASIC discussed herein is a Microsoft product available on IBM machines as IBM BASIC and on many compatible machines as GW BASIC. In either case the version must be recent enough that the SHELL command is available. The FORTRAN compiler used in writing the example program discussed later is the Microsoft Optimizing Compiler, version

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1987.tb00148.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

For a ductile material such as steel, the stressstrain curve may be taken as linear up to the yield point and then indefinitely horizontal. Under this assumption, the first‐named author has shown in 1963 that the response of a continuous beam or rigid frame under increasing loads may be traced from the beginning to collapse by a stepwise elastic analysis procedure. This procedure requires that the structure is subjected to concentrated loads only so that plastic hinges can form only at the ends of the elements which are themselves unloaded. In this paper, this restriction is removed by allowing uniform and concentrated loads to act on the elements. Consequently, a plastic hinge may form anywhere on an element, and the fixed‐end moments and the stiffness coefficients of that element must then be modified for the next stage of elastic analysis. The advantage gained is enormous because previously a uniform load has to be replaced by a number of concentrated loads and a node placed at any point where there is a concentrated l

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1987.tb00149.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Parallel processing is appearing as a promising approach to large‐scale engineering computations. High performance can be achieved by using powerful microprocessors in parallel. The research challenge is to reformulate the problem, develop parallel algorithms, and devise new computational stratagems in order to utilize fully the capabilities of parallel machines. This article presents a review of parallel processing including various interconnection networks in multiprocessors, commercial parallel processors, and parallel programming languages and algorithms. Present applications of parallel processing in civil engineering are also describe

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1987.tb00150.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1987.tb00151.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY