Integration of engineering models in computer-aided preliminary design

Abstract

The problems of the integration of engineering models in computer-aided preliminary design are reviewed. This paper details the research, development, and testing of modifications to Paper Airplane, a LISP-based computer program, designed to address these integration problems. Paper Airplane integrates engineering models by treating them like a set of simultaneous non-linear functions and numerically solving for them as such. The original version of Paper Airplane could only handle engineering models represented by single equations and simple LISP functions; that is, multiple-input single-output (MISO) functions. The modifications to Paper Airplane were to allow it to handle engineering models represented as complex LISP functions and external computer programs as well; that is, multiple-input multiple-output (MIMO) functions. The research was divided into three tasks: (1) to get Paper Airplane to communicate with an external computer program (without changing the computer program), (2) to get Paper Airplane to numerically solve a non-linear MIMO function, and (3) to get Paper Airplane to numerically solve a set of simultaneous non-linear functions made up of MISO and MIMO functions.