MSc. Thesis Defense:Yaser Mohammadi
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  • MSc. Thesis Defense:Yaser Mohammadi

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ON DYNAMICS OF MULTI-MODE SYSTEMS:

PROCESS DAMPING EFFECT & FRF MODIFICATION

 

Yaser Mohammadi
Manufacturing, MSc. Thesis, 2017

 

Thesis Jury

Prof. Erhan Budak (Thesis Advisor), Assist. Prof. Lutfi Taner Tunc (Thesis Co-advisor), Assoc.Prof. Oğuzhan Yılmaz, Assoc. Prof. Volkan Patoğlu, Assist. Prof.Bekir Bediz

 

 

Date & Time: 25th, July 2014 –  10:00 AM

Place: FENS G032

Keywords : Multi-mode systems, Process damping, Stability lobes diagram, Chatter, FRF modification, Modes interaction

 

Abstract

 

Dynamic response of machining systems is the primary information required for determining stability behavior. For the sake of simplicity, machining systems are normally treated as single mode systems in many researches. However, considering multi-mode characteristics and effects of multiple modes introduce new features to machining dynamics. In this thesis, two topics are studied on systems with multiple modes. First, the effect of process damping in multi-mode milling systems is investigated. Stability lobes diagrams are constructed through frequency domain solution and a time domain model is presented to simulate vibrations of the cutting tool. Effects of modes with different frequencies on stability frontier at low speeds are presented and verified experimentally. As the second part of this research, a methodology is developed to modify the dynamic response of structures with respect to their multi-mode characteristics. Using this methodology, the transfer function of a structure can be modified through interaction of structure’s modes. Tool-tip transfer function of a milling machine tool is suppressed and verification has been done through hammer impact tests.