摘要:

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 s

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1991.tb00402.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract:This paper describes the development of KASTLE—a knowledge‐based system for synthesis and design of steel lattice self‐supporting transmission towers. Using inputs such as type of tower, geographical location, the voltage the conductor has to carry and the number of circuits the tower has to support, an experienced designer arrives at an overall configuration of tower. An expert designer basically relies on heuristics to choose parameters, such as base width, tophamper width, type of bracings and sub‐bracing pattern, for the tower configuration. The final cost of the tower is sensitive to these initial decisions. Geometric modelling of the configuration is prerequisite for tower analysis. This paper reports an attempt to integrate different types of knowledge‐based systems using blackboard architecture. The knowledge system for configuration generation uses theorem proving, whereas in other knowledge‐based systems, such as modelling and design heuristics, knowledge has been represented using IF‐THEN rules. A sample synthesis and design of a 220 kV and 400 kV tangent tower is included. The system has been implemented on an IBM PC AT with MS‐DOS. Prolog, Fortran, and C lang

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1991.tb00403.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract:Computer simulation can provide an eficient and cost‐effective method of analyzing project alternatives, resource constraints and potential progress. It is frequently performed to study the behavior of a system in an attempt to improve performance. There are many different analytical methods that can be used to plan or analyze a construction operation. However, in most cases, analytical techniques require abstractions which tend to reduce confidence in model predictions. These methods do, however, offer a basis for validating simulation results. This paper illustrates how Micro CYCLONE, a microcomputer‐based simulation language, can be used to measure job productivity in construction. It also illustrates how BetaFit, a microcomputer‐based program, can be used to model accurately and eficiently random processes for use in the simulation experiments. The paper also presents a framework for validating construction simulation by reviewing the application of two analytical methods. A roof truss process is modeled using the CYCLONE methodology and then validated using queueing theory and method productivity delay modeling to illustrate the various proce

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1991.tb00404.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract:The partial hybrid stress method is applied to the Mindlin plate theory for orthotropic composite plates. The displacement formulation is adopted in the flexurel part and the hybrid formulation in the transverse shear part. Since the interface traction discontinuity is overcome, the present element performs much better than the displacement‐based method. Although only the stress parameters in transverse shear part are required, the accuracy approaches that of the conventional hybrid method, The governing equations of plate are also derived from the modified Hellinger‐Reissner variational princi

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1991.tb00405.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract:The dynamic stiffness method can predict an infinite number of natural modes of a conservative structure by means of a finite number of coordinates. The methos is extended to a nonconservative system characterized by follower moments to investigate the dynamic lateral buckling and flutter in this paper. Straight beam members with doubly symmetrical cross‐sections are of interest, and skeletal frames are taken as examples. Flexural and torsional modes are coupled. The fact that the applied moment softens the flexural modes, but hardens the torsional modes, makes the characteristic diagram much more complicated than that of follower forces. Isola loops are possibl

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1991.tb00406.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract:This paper addresses the application of C languagees in developing hydraulic engineering software and depicts the implementation and the rigorous verification of a gererally applicable finite difference numerical model, tailored for use on the IBM PC/XT or PC/AT personal computers, for simulation of unsteady open channel flow. The program is written in the C language, compiling and executing under the integrated program environment TURBO C version 2.0. The various advantages and limitations of employing the TERBO C environment in developing hydraulic engineering software are also presented thoroughly. In the development of the mathematical model, apart from the simplified channel tests where analytical results are available. The program's successful application provides confidence for its capablity as a predictive tool in situations involving complex bathymetry and/or nonlinear bottom frictional effects.

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1991.tb00407.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract:This Paper explores the relation between the number of generalized displacement coordinates and finite element solution accuracy as a function of the class of boundary conditions. The study concludes that strain energy estimates for well‐behaved potential energy element models may be mulitvalued for successively finer grids. When the only non‐zero boundary values are nodal forces, the problem is minimax. When the only non‐zero boundary conditions are settlements, the problem is minimin. When boundary conditions involve a mix of nodal forces and settlements, multivalued convergence curves may arise. The authors suggest the use of superposition to circumvent non‐monotonic conv

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1991.tb00408.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract:Using a two‐step iterative technique, a solution is obtained for the response of axially‐loaded piles embedded in yielding soils. The proposed method can be applied to both floating and end‐bearing piles and examples have been provided to demonstrate such analyses. For the case of an end‐bearing pile model is shown to provide a close match against a collocation based model. As shown in the appended listing of the code, the proposed model is easy to implement and can perform efficiently on conventional micro‐

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1991.tb00409.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY