TEACHING MACHINE DYNAMICS IN A VIRTUAL LABORATORY: SIMULATION OF FREE AND FORCED VIBRATIONS OF A HOMOGENEOUS BAR

The functioning of various mechanical systems and machinery is often characterized by vibratory phenomena. Some of these are beneficial, as they are at the basis of the working principle of the system; others are harmful, as they occur like a secondary phenomenon with negative consequences on the precision or on the lifespan of the system, as well as on the comfort or on the health of the operator. For this reason, the study of vibrations is an essential component of the higher education in technical universities with mechanical engineering curricula. The study of bar vibrations is a course chapter to which a particular importance is given as, on one part, bars are the simplest continuous systems and, on the other part, several machine parts can be modeled as bars. The authors have developed an e-learning application for the animated graphic simulation of the free and forced vibrations of straight homogeneous bars, with various end conditions. The application is part of an e-learning software suite they have been developing, as a virtual laboratory, for over a decade, and that is currently in use at the “Politehnica” University of Bucharest during the application sessions in engineering faculties. By its use, students can interactively observe the effects of various end conditions and input parameters on bar vibrations, thus linking more easily the theoretical aspects taught at the course with the observed output.