Analiza stabilnosti struženja

Porenta, Mark (author), Pušavec, Franci (mentor)

Samovzbujene vibracije, imenovane drdranje, so ena izmed glavnih omejitev produktivnosti odrezovalnih procesov. Napovedovanje nestabilnih področij je zato zelo pomembno, vendar je zaradi številnih nelinearnosti v procesu analitično težko dosegljivo. Magistrska naloga analizira stabilnost struženja v časovni domeni z reševanjem diferencialnih enačb z zamikom. Predstavili smo teoretične osnove mehanike in dinamike odrezavanja. Izvedli smo eksperimente struženja za določitev komponent sil v odvisnosti od podajanja in globine rezanja, ki smo jih aproksimirali s polinomom. Izvedli modalno analizo orodja z držalom in določili prenosno funkcijo odziva na vzbujanje v podajalni smeri. Rezultate iz obeh delov smo uporabili v gibalni enačbi sistema drdranja, ki smo jo numerično reševali s kodo dde23 v programskem okolju Matlab. Z analizo rezultatov simulacij smo formirali stabilnostni diagram, ki upošteva nelinearno odvisnost sile od debeline odrezka in nelinearnost, ki se pojavi ob skoku orodja iz materiala. Pokazali smo, da je z reševanjem diferencialnih enačb z zamikom možno simulirati drdranje v procesu struženja in pri tem upoštevati nelinearnosti, kar pri analizi v frekvenčni domeni ni mogoče.

• Language: Slovenian
• Keywords: struženje, drdranje, mehanika odrezavanja, dinamika odrezavanja, modalna analiza, diferencialne enačbe z zamikom
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FS - Faculty of Mechanical Engineering
• Place of publishing: Ljubljana
• Publisher: [M. Porenta]
• Year: 2023
• Number of pages: XX, 62 str.
• PID: 20.500.12556/RUL-150142
• UDC: 621.941:531/534:517.9(043.2)
• COBISS.SI-ID: 166533891
• Publication date in RUL: 14.09.2023

PORENTA, Mark, 2023, Analiza stabilnosti struženja [online]. Master’s thesis. Ljubljana : M. Porenta. [Accessed 26 April 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=150142

Secondary language

• Language: English
• Title: Analysis of turning process stability

Abstract

Self-induced vibrations, known as chatter, are one of the main limitations to the productivity of cutting processes. Prediction of unstable areas is therefore very important but is analytically difficult to achieve due to the many non-linearities in the process. This thesis analyses the stability of turning in the time domain by solving delay differential equations. We presented the theoretical foundations of the mechanics and dynamics of turning. We carried out turning experiments to determine the force components as a function of feed and depth of cut and approximated them by a polynomial. We conducted modal analysis of the tool with the toolholder and determined the transfer function of the response to excitation in the feed direction. We used the results from both measurements in the equation of motion of the chatter system, which we solved numerically with the code dde23 in Matlab. By analyzing the results of the simulations, we formulated the stability diagram, considering the non-linear dependence of the force on the thickness of the chip and the non-linearity that occurs when the tool jumps out of the material. We have shown that by solving delay differential equations it is possible to simulate chatter in the turning process while accounting for the nonlinearities, which is not possible in frequency domain analysis.

• Keywords: turning, chatter, cutting mechanics, cutting dynamics, modal analysis, delay differential equations