scholarly journals Computer Aided Nonlinear Analysis of Machine Tool Vibrations and a Developed Computer Software

2005 ◽  
Vol 10 (3) ◽  
pp. 377-385 ◽  
Author(s):  
Ahmet Taskesen ◽  
Yucel Ercan
Author(s):  
Sorrek Penn-Edwards

The qualitative research methodology of phenomenography has traditionally required a manual sorting and analysis of interview data. In this paper I explore a potential means of streamlining this procedure by considering a computer aided process not previously reported upon. Two methods of lexicological analysis, manual and automatic, were examined from a phenomenographical perspective and compared. It was found that the computer aided process - Leximancer - was a valid investigative tool for use in phenomenography. Using Leximancer was more efficacious than manual operation; the researcher was able to deal with large amounts of data without bias, identify a broader span of syntactic properties, increase reliability, and facilitate reproducibility. The introduction of a computer aided methodology might also encourage other qualitative researchers to engage with phenomenography.


2021 ◽  
Vol 55 ◽  
pp. 568-575
Author(s):  
Michal Richtarik ◽  
Martin Gavlas ◽  
Mário Drbúl ◽  
Andrej Czán ◽  
Milan Sága
Keyword(s):  

Author(s):  
Amir Nankali ◽  
Young S. Lee ◽  
Tamás Kalmár-Nagy

We study the dynamics of targeted energy transfers in suppressing chatter instability in a single-degree-of-freedom (SDOF) machine tool system. The nonlinear regenerative (time-delayed) cutting force is a main source of machine tool vibrations (chatter). We introduce an ungrounded nonlinear energy sink (NES) coupled to the tool, by which energy transfers from the tool to the NES and efficient dissipation can be realized during chatter. Studying variations of a transition curve with respect to the NES parameters, we analytically show that the location of the Hopf bifurcation point is influenced only by the NES mass and damping coefficient. We demonstrate that application of a well-designed NES renders the subcritical limit cycle oscillations (LCOs) into supercritical ones, followed by Neimark–Sacker and saddle-node bifurcations, which help to increase the stability margin in machining. Numerical and asymptotic bifurcation analyses are performed and three suppression mechanisms are identified. The asymptotic stability analysis is performed to study the domains of attraction for these suppression mechanisms which exhibit good agreement with the bifurcations sets obtained from the numerical continuation methods. The results will help to design nonlinear energy sinks for passive control of regenerative instabilities in machining.


Sign in / Sign up

Export Citation Format

Share Document