This paper describes STRAIN (STructural Analysis INteractive), an interactive computer graphics system for analysis of skeletal structures. The system uses the stiffness method of structural analysis. The method is developed using the terminology and notation of the program. Skeletal structural analysis problems are well-suited for graphical display because of their physical configurations and the use of diagrams in representing the results. In the structural design process, an interactive mode of operation is very desirable due to the necessity of changing the problem parameters. The STRAIN system operates interactively with graphical displays meeting the above desired capabilities. STRAIN operates in a heuristic mode allowing the user to view various displays and to change certain structure properties. The displays which may be viewed are: geometric configuration of the structure; structure under loads; applied loads tabulation; structure data tabulation; member-end actions tabulation; shear and moment diagrams for all members; and the deflected structure. In conjunction with certain of these displays, the loading condition may be changed and any of the member properties may be altered. Any particular problem may be solved as many times as the user wishes and any number of problems may be solved.
Ewald, Robert Hansen, "STRAIN - An Interactive Computer Graphics System for the Analysis of Skeletal Structures" (1970). University Libraries Digitized Theses 189x-20xx. 34.