Identifying the modal behaviour of rotary equipment via estimation method
Subject Areas : Modal Analysis
Hossein Pirzadeh
1
,
Alireza Mohammadion
2
,
Armen Adamian
3
1 - Department of Mechanical Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran
2 - Department of Mechanical Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran
3 - Department of Mechanical Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran.
Keywords: modal, predictive method, Rotary Equipment,
Abstract :
In this article we aim to study the modal behaviour of rotary equipment via predictive method with two examinations. Exam 1: identifying of a complete system without need to measuring of one row of FRF matrix while one column of this matrix is identified. The whole examination is simulated with rotor at four freedom degree. Exam 2: identifying the available parameters in an industrial system which was not considered in exam 1. The experimental system is a continuous vibration system, so in order to identify such a system, we need to use a method that describe it into a discrete system to illustrate the turbulences in data measuring. After that, we can explain the continuous system with a short model at a certain frequency band. Furthermore, we can estimate the modal parameters. It is also showed that the accuracy which special left vectors were determined can actually affected by the accuracy of modal constants related to the measured data. As a result, the special left vectors are affected by turbulences of the measured data. The effects of turbulences on freedom degrees with small response amplitude at bond frequency in the vicinity of closed modes, are more distinguished. Despite of the vibrations, the predicted special left vectors for determining one row of FRF matrix is suitable with one measured column.
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