Analysis of Torsional Vibration Inherent Characteristics of Gear Shaft
The transfer matrix method and the finite element method are used to calculate the torsional vibration inherent characteristics of the gear shaft of the motor-driven feed pump. The transfer matrix method needs to establish the multi-segment concentrated mass model of the shafting system. The finite element method is used to establish the model of the shaft system with gears by using ANSYS software. The gears are set using the matrix unit Matrix27.The results of the two methods are compared to ensure the accuracy of the model Consider the gear shaft with the role of bending and torsion obvious, based on the established nonlinear model of gear shaft system, the differential equation of gear kinematics is deduced, and the stiffness coupling in Matrix27 is modified by obtaining the stiffness matrix. The final calculation results show that the gear shaft system has a new frequency Appears, and some frequencies and some of the frequency is not coupled, there will be some changes. INTRODUCTION Pump and fan auxiliaries are the major energy users in nuclear power plants and thermal power plants, which account for more than 80% of the house supply, When the major power generation groups are carrying out or planning the frequency conversion or double speed transformation of the auxiliary equipment, the research focuses are mostly on the necessity of transformation [1] , However, with the operation of induced draft fan and feed pump in frequency conversion or double speed transformation, some security problems occurred, Such as vibration is too large, shaft fracture, etc. Such accidents have also occurred in China [2] . There are many reasons for this kind of accidents, this paper tries to identify the natural frequency of torsional vibration from the analysis of the inherent characteristics of the structure, in the design, if the rotational speed effectively avoids the natural frequency of the shafting, it will be of great help to the selection of the equipment [1][2] . *First author: Shen-bin Nie, Senior Engineer, Suzhou Nuclear Power Research Institute, Shenzhen, China 518000 Second author Ming-xiang Gong, Suzhou Nuclear Power Research Institute, Shenzhen, China 518000