INTRODUCTION OF MASS POINTS INTO THE FINITE ELEMENT METHOD FOR THE DYNAMIC BEHAVIOR MODELING OF ROTATING MACHINE

摘要

The dynamic modeling of the rotating machines system is required to understand their dynamic behavior and the associated vibration problems. Fortunately, this modeling has seen a great development, since the use of Timoshenko or Euler-Bernoulli beam, followed by the Jeffcott and Laval rotor until using fine and complex techniques these days. Unfortunately, this development remains still insufficient to describe in a realistic way the dynamic behavior, in particular the rotor. Nowadays, the using of the finite element method, which is considered as the powerful numerical tool, gave a great help. This method can model as real as possible the phenomena that influence the rotor behavior, but this tool remains inapplicable to describe its behavior when it undergoes at the same time motion, deformations and the faults effects. To resolve these problems, a number of mathematical artifices are used, but, these methods are some times very difficult or are too complex and the result obtained is not always as good as it hopes. In fact, the deformed rotor resolution method is reduced to a modal solution, which does not show the real deformations during time in many cases. In order to simplify the resolution and to show rotor movement with deformation under faults effects, a method is proposed to allow a better approach of this problem. This method is based on subdividing the structure to mass-point sections that make possible to consider the rotational motion with deformations of the rotors. In this work, the above method is implemented on engineering simulation software dedicated for rotordynamics, and the calculation results are validated against experimental data of fault simulations in rotors as presented in the following sections of this paper.