Rotor balancing using parametric combination resonance

• Grant number: 18/05703-3
• Support Opportunities: Scholarships abroad - Research
• Start date: June 30, 2018
• End date: July 29, 2018
• Field of knowledge: Engineering - Mechanical Engineering - Mechanics of Solids
• Principal Investigator: Ricardo Ugliara Mendes
• Grantee: Ricardo Ugliara Mendes
• Host Investigator: Fadi Dohnal
• Host Institution: Centro Tecnológico da Marinha em São Paulo (CTMSP). Ministério da Defesa (Brasil). São Paulo , SP, Brazil
• Institution abroad: University for Health Sciences, Medical Informatics and Technology (UMIT), Austria
• Associated research grant: 15/20363-6 - Fault tolerant identification and control of rotating systems, AP.TEM

Abstract

In traditional modal balancing, the rotor response close to each critical speed, correspondent to the modes of interest, is measured; this ensures a representative response of each mode to be balanced. The main disadvantage of this procedure is the time consumed during run-up/run-down cycles. Besides, several critical speeds are passed, which may cause high levels of vibration or even several run-ups if the resulting unbalance is critical. Recently, a new balancing method in which the system needs to rotate up to the first critical speed only was proposed in cooperation with Prof. Dr. Fadi Dohnal. In this method, active magnetic bearings are used to introduce a parametric excitation at different parametric combination resonances, inducing a modal energy transfer from the first critical speed to higher modes. This allows for estimating influence coefficients and corresponding correction masses at low speed. The proposed method avoids the need for spinning the rotor above its first critical speed; thus, saving time and allowing for high-speed rotor balancing at low speed. The objective of this project is to continue the development of the proposed method. The method sensitivity to the gyroscopic effect and to the parametric excitation amplitude and frequency are the main topics to be developed. The proposed balancing method is inserted into the context of unbalance identification in the FAPESP thematic project (grant #2015/20363-6), and a closer cooperation with Prof. Dr. Fadi Dohnal would be particularly interesting since he is a leading researcher in the field of parametrically excited systems, more specifically, rotating machines. (AU)