|Support type:||Scholarships in Brazil - Doctorate|
|Effective date (Start):||April 01, 2015|
|Effective date (End):||March 31, 2018|
|Field of knowledge:||Engineering - Mechanical Engineering|
|Principal researcher:||Maira Martins da Silva|
|Grantee:||Giuliana Sardi Venter|
|Home Institution:||Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil|
Machining operations can achieve higher productivity and higher quality parts when chatter is monitored and appropriately suppressed. Chatter is a self excited vibration that can cause instability during machining processes, which affects the efficiency, reduces tool life and can cause noise. The regeneration of chip thickness, which is related to phase between the modulations left on the surface during the successive cuts, is the most common reason behind the phenomenon of chatter instability. A first numerical and experimental study on the reduction of chatter using piezoelectric material was carried out during the project CNPq Universal 470314/2010-9 and IC FAPESP 2011/17166-3. This work continued with the masters scholarship FAPESP 2012 / 22470-6. During these studies, it was experimentally verified the coupling of the first vibration modes of the toolholder, causing significant nonlinearities in the process. Such nonlinearities have been studied and a model for the system was proposed in the master project. Experiments using an passive control were also performed, confirming the coupling between modes and vibration reduction through control methods that increase the system damping. However, the results of the chatter reduction using only passive control are not yet satisfactory. Thus, in the first step of this research project, it is proposed to conduct the fit of the model proposed in the master's project FAPESP 2012 / 22470-6, so it can be used in the proposed active vibration control model. In a second step, it is proposed to seek alternatives to reduce the chatter through active control using multilayer piezoelectric material attached to the tool holder. Finally, the best alternative should be applied to the real system and the reduction of chatter must be proven. The materials needed for the development of this research will be purchased during the term of universal project CNPq 479342/2012-1. It is expected that the application of the best control strategy can significantly reduce this vibration during machining instability, making it a more economically productive and efficient process.