CAL-GRAF—a computer-graphics supplement for CAL

Abstract

The computer analysis language CAL developed by Wilson[1] has proven to be a valuable tool in the teaching of modern methods of static and dynamic analysis of structural systems. The language has now been extended to cover the fundamental operations involved in composing graphic displays of various computational aspects of these methods on a screen and on paper. The computer graphics supplement CAL-GRAF covers the graphical representation of GRids And Functions. The purpose of the supplement is to allow students to graphically check the geometry and topology of their models, and to help them to interpret the results of their computations, such as, for example, displacements and stress resultants. CAL-GRAF consists of four types of operations: service operations, geometry processing, plotting of grids, and plotting of functions. Operations for extracting element topology tables and node and element related results have been added to CAL. Following the underlying philosophy of CAL, the composition of a graphical frame is subdivided into a logical sequence of separated CAL and CAL-GRAF operations. The new operations are formulated in the general form of the CAL operations and are embedded in the data management system of CAL. Examples are presented of applications to membrane/plate models with a plate element[2] which has recently been added to CAL.