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شبیه‌سازی اجزاء محدود وقوع لرزش در تراشکاری و فرزکاری با هندسه متعامد، با در ‌نظر گرفتن دینامیک دو بعدی ماشین‌ابزار
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شبیه‌سازی اجزاء محدود وقوع لرزش در تراشکاری و فرزکاری با هندسه متعامد، با در ‌نظر گرفتن دینامیک دو بعدی ماشین‌ابزار

جعفرزاده، احسان Jafarzadeh, Ehsan

Finite Element Simulation of Machining Chatter in Turning and Milling with Orthogonal Geometry, Taking into Account of Two-Dimensional Machine Tool Dynamics

Jafarzadeh, Ehsan | 2016

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 48517 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Movahhedy, Mohammad Reza; Khodaygan, Saeed
  7. Abstract:
  8. Chatter vibration is a major obstacle in high quality machining. This undesirable vibration decreases the production rate, surface quality, tool life and machine tool life. In the last few decades, a lot of models have been presented to predict chatter. Most of the models, whether linear or nonlinear, have focused on modeling of machine tool dynamics and either disregard the effective parameters of chip formation process or apply some of these parameters through simplified equations. In this research, a finite element simulation of chip formation is combined with the dynamics of machine tool to investigate chatter and its effective factors. The proposed approach, unlike common mathematical methods, has the ability of considering most of the linear and nonlinear factors affecting chatter. To this end, a two-dimensional model of the tool and work piece is created in MSC Marc commercial software for milling and turning with orthogonal geometry and then the dynamics of machine tool is applied by springs and dampers which are connected to the tool as the representative of the tool and machine tool in two directions. The dynamic parameters are obtained by experimental modal analysis. As a result, the tool can vibrate as a result of chip thickness vibration leading to chatter which is used as a criterion to determine the stability of the system. The results of investigating mode coupling and regeneration phenomenon in turning show that a one-dimensional model predicts a more stable machining process than it actually is, due to the role of mode coupling. It can be said that the effect of mode coupling in the first pass of machining cannot be disregarded in decreasing the stability of the process. However, in the whole of process, the role of regeneration is more dominant than mode coupling. Results also show that increasing width of cut in turning and axial depth of cut, radial immersion and feed rate in milling lead to a more unstable process
  9. Keywords:
  10. Machining Chatter ; Finite Element Method ; Two Dimensional Model ; Turning ; Milling ; Modal Test

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