Automatic Generation and Automatic Analysis of Equations of Motion from the Graphic Input of a Vibration Model

Abstract

In order to make vibration analysis an easy and automated task for designers, an interactive vibration-analysis system was developed. The system has the following advantages. (1) The system has a user-friendly interface for graphic input of vibration models which enables users to make figures of vibration models on the display by choosing the vibration-model elements listed in the menus with a pointing device (mouse). (2) The system can perform automatic generation of equations of motion from the graphic input and automatic numerical analysis including eigenvalue analysis and time-history analysis. (3) The system is applicable to extensive models of two-dimensional and three-dimensional vibration of multibody systems which can contain various constraints and nonlinear elements including a friction element, an elastoplastic hysteresis element and nonlinear springs/dampers defined by users. The main part of the system was written in Smalltalk-80 and the part for numerical analysis was written in C.