Computer-Aided Design of Trusses Using TURBO PASCAL

This article presents interactive microcomputer-aided design (MicroCAD) of steel plane trusses. A menu-driven graphic-based MicroCAD system has been developed for interactive analysis and design of statically determinate and indeterminate steel trusses using TURBO PASCAL Version 3.0 on an IBM PC with 256K of random access memory (RAM), called TRUSS2P. TRUSS2P makes extensive use of computer graphics for showing various configurations of the truss with or without joint numbering, member numbering, loading, member type numbering, cross sections of the members, and its deformed configuration under various loading conditions. Graphic manipulation capabilities of TRUSS2P are zooming, panning, scaling, rotating, shrinking, and expanding. Among the features of TRUSS2P are on-line input modification capability, modify input menus, input error check, and automatic data generation and replication for nodal coordinates, member information, and loading on the truss. Member design information can be displayed for each member through split-screen graphic-text displays.     

Parallel Processing

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 described.     

Parallel Structural Analysis Using Threads

Practical solution of the structural analysis problem in a parallel processing environment is investigated through the use of the notion of cheap concurrency and the concept of threads. A thread is a lightweight process or independent instructions executing agent capable of concurrent execution with other threads. Portions of a structural analysis code implemented in C have been parallelized employing the Encore Parallel Threads on an Encore Multimax multiprocessor computer. The issues of racing condition, synchronization, and mapping are considered and discussed. Two synchronization mechanisms, semaphores and monitors, have been employed and compared. Two different mapping strategies have been implemented and studied. Results are reported on the effect of amount and frequency of shared memory access on the speed-up, the overhead time required for creating threads, and comparison of overall computational time performance using two space truss examples. An overall efficiency of 90–95% was achieved for 11 processors.     

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.     

Structuring Knowledge and Data Bases in Expert Systems for Integrated Structural Design

The integrated structural design includes preliminary design, structural analysis, and the final detailed design. A knowledge-based expert system for integrated structural design requires both symbolic processing of heuristics and experiential knowledge and numerical processing of algorithmic computations. In addition, such a coupled expert system must use existing data bases as well as a large variety of data created during a consultation with the system. Thus, considering their complex interaction, effective integration of symbolic processing, numerical processing, and data base management becomes a major concern in the development of expert systems for integrated structural design. This paper addresses this integration problem by presenting a prototype system, called FRAMEX, for design of a class of steel structures—regular multistory steel buildings. The basis of steel design is the recently developed Load and Resistance Factor Design Specification.     

New Generation Microcomputers: Part I: 80386 Machines

This article presents a review of new generation microcomputers using the Intel 32-bit 80386 processor. They include ISM PSI2 Model 80, Compaq Deskpro 386, Kaypro 386, ALR Access 386, and Tandy 4000. Some of the powerful 16-bit 80286-based machines introduced into the market recently are also reviewed. They include the IBM PS/2 Models 50 and 60 and Compaq Portable III.