Dissertation > Industrial Technology > Machinery and Instrument Industry > Mechanics (mechanical design of the basic theory ) > Mechanical kinetics

Reliability-based Sensitivity Research on Multi-span Rotor System

Author ZhuLiSha
Tutor ZhangYiMin
School Northeastern University
Course Mechanical Design and Theory
Keywords reliability FEM rotor system dynamic analysis ANN sensitivity
Type Master's thesis
Year 2009
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Rotary machine is the heart of basic industry in a country. It plays a very important role in the national economy. The rotor system is made up of complex components and affected obviously by high rotating speed, unbalance force or torque, oil whip, gas surging and so on. Besides, because the rotating axis is flexible and affected by complex working condition, it will bring high dynamic stress. If dynamic stress exceeded yield limit, the rotor system would come to failure in the design stage. In case that the designed parameters were not suitable, the work were abnormality so that very serious accidents would be happened which posed a threat to human’s lives. As a result, it has great significance to study on how to build up safety tolerance reasonably and control the designed parameters’ influence on the reliability of rotor system.Based on the research of mechanical component reliability and rotor dynamics, the paper study on the reliability-based sensitivity of rotor system as following steps, firstly, complex rotor system is simplified reasonably, virtual prototype model with rigid-flex system is established, dynamic characteristic of the rotor system is analyzed with the finite element method, the unbalance response and distribution of maximum dynamic stress is obtained in the post-processing stage. And then, in consideration of the limitation of past numerical method to solve structural reliability, according to the theory about reliability, the paper adopts neural network technology combined with FEM to solve the tough problem because it has high nonlinear mapping function and can approach arbitrary function. At last, because the basic random parameters are blended, that is, the units of parameters are different respectively so that there is no comparability between parameters’ sensitivity. The paper gets the dimensionless form and influence degree order of the sensitivity based on the theory of reliability sensitivity. Providing theoretical reference for the designed parameters of the rotor system, there is positive realistic meaning and economic value.

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