TY - JOUR AU - Béri, Bence AU - Stépán, Gábor TI - Effect of axial force on the stability of milling: Local bifurcations around stable islands JF - JOURNAL OF VIBRATION AND CONTROL J2 - J VIB CONTROL VL - 29 PY - 2023 IS - 1-2 SP - 440 EP - 452 PG - 13 SN - 1077-5463 DO - 10.1177/10775463211048256 UR - https://m2.mtmt.hu/api/publication/32510579 ID - 32510579 N1 - Funding Agency and Grant Number: New National Excellence Program of the Ministry for Innovation and Technology from the national research, development and innovation fund [UNKP-20-3]; NRDI Fund (TKP2020 NC) of the Ministry for Innovation and TechnologyNational Research, Development & Innovation Office (NRDIO) - Hungary [BMENC]; Hungarian National Research, Development and Innovation OfficeNational Research, Development & Innovation Office (NRDIO) - Hungary [NKFI-K-132477, NKFI-KKP-133846] Funding text: The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This research was supported by the UNKP-20-3 New National Excellence Program of the Ministry for Innovation and Technology from the source of the national research, development and innovation fund, by the NRDI Fund (TKP2020 NC,Grant No. BMENC) based on the charter of bolster issued by the NRDI Office under the auspices of the Ministry for Innovation and Technology and by the Hungarian National Research, Development and Innovation Office (NKFI-K-132477 and NKFI-KKP-133846). AB - In this paper, the stability properties of milling processes are presented when the axial component of the cutting force is also taken into account as a compressive force acting on the cutting tool. The mechanism of the material removal operation is described by a one degree-of-freedom oscillator subjected to the so-called surface regeneration effect. This can be represented mathematically by a nonlinear, time-periodic, delay differential equation. The regenerative compression affects the natural frequency of the system, which is modelled through the lateral stiffness variation of the bearing support of the main spindle. This extension of the general milling model leads to the birth of stable islands within the originally unstable parameter domain. Since the exploitation of these regions may open new ways in practice for increasing the efficiency of machining, the domain of attraction is investigated qualitatively near the stability boundaries of the stable island by means of a semi-analytical method. LA - English DB - MTMT ER - TY - JOUR AU - Habtour, Ed AU - Di Maio, Dario AU - Masmeijer, Thijs AU - Gonzalez, Laura Cordova AU - Tinga, Tiedo TI - Highly Sensitive Nonlinear Identification to Track Early Fatigue Signs in Flexible Structures JF - Journal of Nondestructive Evaluation, Diagnostics and Prognostics of Engineering Systems VL - 5 PY - 2022 IS - 2 PG - 12 SN - 2572-3901 DO - 10.1115/1.4052420 UR - https://m2.mtmt.hu/api/publication/33917013 ID - 33917013 AB - This study describes a physics-based and data-driven nonlinear system identification (NSI) approach for detecting early fatigue damage due to vibratory loads. The approach also allows for tracking the evolution of damage in real-time. Nonlinear parameters such as geometric stiffness, cubic damping, and phase angle shift can be estimated as a function of fatigue cycles, which are demonstrated experimentally using flexible aluminum 7075-T6 structures exposed to vibration. NSI is utilized to create and update nonlinear frequency response functions, backbone curves and phase traces to visualize and estimate the structural health. Findings show that the dynamic phase is more sensitive to the evolution of early fatigue damage than nonlinear parameters such as the geometric stiffness and cubic damping parameters. A modified Carrella-Ewins method is introduced to calculate the backbone from nonlinear signal response, which is in good agreement with the numerical and harmonic balance results. The phase tracing method is presented, which appears to detect damage after approximately 40% of fatigue life, while the geometric stiffness and cubic damping parameters are capable of detecting fatigue damage after approximately 50% of the life-cycle. LA - English DB - MTMT ER - TY - JOUR AU - Mohammadi, Yaser AU - Ahmadi, Keivan TI - Finite-amplitude stability in regenerative chatter: The effect of process damping nonlinearity and intermittent cutting in turning JF - JOURNAL OF SOUND AND VIBRATION J2 - J SOUND VIB VL - 537 PY - 2022 PG - 13 SN - 0022-460X DO - 10.1016/j.jsv.2022.117158 UR - https://m2.mtmt.hu/api/publication/33344948 ID - 33344948 AB - The damping forces generated at the tool and workpiece interface, known as process damping, greatly influence the dynamics of regenerative chatter in machining. In addition to the increased stability against chatter at low cutting speeds, which is the well-known effect of process damping, post-chatter dynamics are also affected significantly by process damping nonlinearity, which is the less-studied effect of this phenomenon. Once the process vibrations become unstable after chatter occurrence, the process becomes intermittent in the sense that the tool loses contact with the workpiece and they are no longer in continuous engagement due to large-amplitude chatter vibrations. When vibration amplitudes are relatively large, process damping nonlinearity is shown to create stable limit cycles around which vibrations stabilize at a finite-amplitude. The relationship between the amplitude of the resulting limit cycles and the applied machining parameters is only known approximately from simplified models. Besides, the bifurcation of the resulting limit cycles by machining parameters such as cutting depth and spindle speed has not been studied. In this work, we use numerical continuation to develop the bifurcation diagrams of an SDOF model of regenerative chatter that includes process damping nonlinearity and non-smooth dynamics due to the disengagement of the tool and workpiece in post-chatter large-amplitude oscillations. The developed bifurcation diagrams accurately determine the relationship between the applied machining parameters and the amplitude of the resulting limit cycles. They also show that the stable limit cycles lose their stability by a subcritical non-smooth fold bifurcation when the amplitude is large enough to cause tool-workpiece disengagement. We also show that the static forces in the process, which are normally neglected in existing studies, become dynamic due to the intermittent tool-workpiece disengagement and alter the nature of limit cycle bifurcations. The findings of this study are validated numerically and by comparison to experimental results. LA - English DB - MTMT ER - TY - JOUR AU - Zhang, Zhi AU - Paez Chavez, Joseph AU - Sieber, Jan AU - Liu, Yang TI - Controlling coexisting attractors of a class of non-autonomous dynamical systems JF - PHYSICA D: NONLINEAR PHENOMENA J2 - PHYSICA D: NONLINEAR PEHONOM VL - 431 PY - 2022 PG - 16 SN - 0167-2789 DO - 10.1016/j.physd.2021.133134 UR - https://m2.mtmt.hu/api/publication/33344951 ID - 33344951 AB - This paper studies a control method for switching stable coexisting attractors of a class of non autonomous dynamical systems. The central idea is to introduce a continuous path for the system's trajectory to transition from its original undesired stable attractor to a desired one by varying one of the system parameters according to the information of the desired attractor. The behaviour of the control is studied numerically for both non-smooth and smooth dynamical systems, using a soft-impact and a Duffing oscillators as examples. Special attention is given to identify the parametric regions where the proposed control strategy is applicable by using path-following methods implemented via the continuation platform COCO. It is shown that the proposed control concept can be implemented through either using an external control input or varying a system parameter. Finally, extensive numerical results are presented to validate the proposed control methods. (C) 2021 The Author(s). Published by Elsevier B.V. LA - English DB - MTMT ER - TY - JOUR AU - Sahu, G.N. AU - Jain, P. AU - Wahi, P. AU - Law, M. TI - Emulating bistabilities in turning to devise gain tuning strategies to actively damp them using a hardware-in-the-loop simulator JF - CIRP JOURNAL OF MANUFACTURING SCIENCE AND TECHNOLOGY J2 - CIRP J MANUF SCI TECHNOL VL - 32 PY - 2021 SP - 120 EP - 131 PG - 12 SN - 1755-5817 DO - 10.1016/j.cirpj.2020.11.004 UR - https://m2.mtmt.hu/api/publication/31800524 ID - 31800524 LA - English DB - MTMT ER - TY - JOUR AU - Sahu, Govind N. AU - Law, Mohit AU - Wahi, Pankaj TI - Adaptive control to actively damp bistabilities in highly interrupted turning processes using a hardware-in-the-loop simulator JF - JOURNAL OF VIBRATION AND CONTROL J2 - J VIB CONTROL VL - 1 PY - 2021 IS - 1 SP - 1 EP - 10 PG - 10 SN - 1077-5463 DO - 10.1177/10775463211057968 UR - https://m2.mtmt.hu/api/publication/32575948 ID - 32575948 LA - English DB - MTMT ER - TY - JOUR AU - Shayak, B. TI - Delay dynamics of a levitating motor with two-limit control strategy JF - INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS J2 - INT J NONLINEAR MECH VL - 129 PY - 2021 SP - 1 EP - 8 PG - 8 SN - 0020-7462 DO - 10.1016/j.ijnonlinmec.2020.103645 UR - https://m2.mtmt.hu/api/publication/31682007 ID - 31682007 LA - English DB - MTMT ER - TY - JOUR AU - Sykora, Henrik Tamás AU - Hajdu, Dávid AU - Dombóvári, Zoltán AU - Bachrathy, Dániel TI - Chatter formation during milling due to stochastic noise-induced resonance JF - MECHANICAL SYSTEMS AND SIGNAL PROCESSING J2 - MECH SYST SIGNAL PR VL - 161 PY - 2021 PG - 15 SN - 0888-3270 DO - 10.1016/j.ymssp.2021.107987 UR - https://m2.mtmt.hu/api/publication/32003728 ID - 32003728 LA - English DB - MTMT ER - TY - JOUR AU - Yan, Yao AU - Xu, Jian AU - Wiercigroch, Marian AU - Guo, Qing TI - Statistical basin of attraction in time-delayed cutting dynamics: Modelling and computation JF - PHYSICA D: NONLINEAR PHENOMENA J2 - PHYSICA D: NONLINEAR PEHONOM VL - 416 PY - 2021 PG - 11 SN - 0167-2789 DO - 10.1016/j.physd.2020.132779 UR - https://m2.mtmt.hu/api/publication/32383991 ID - 32383991 AB - This paper proposes a novel concept of the statistical basin of attraction to analyse the multiple stability in nonlinear time-delayed dynamical systems and shows how they can be computed. This concept has been applied to the cutting dynamics, which has been extensively investigated by the authors. Due to the nonlinearity and non-smoothness of tool-workpiece interactions, the cutting dynamics always exhibit large-amplitude chatter entering a linearly stable zone, making the area below stability boundaries unsafe for high material removal rates. Meanwhile, a thorough investigation of the multiple stability in the cutting dynamics is hampered by infinite-many dimensions introduced by time delays, which induce difficulties in computation and visualization of the conventional basin of attraction. To address this issue, infinite-many dimensional time-delayed states are approximated by a Fourier series aligned on a straight line, and the coefficients of the basis functions and the cutting process are used to construct the statistical basin of attraction. Inside the statistical basin of attraction, a safe basin with no probability of chatter occurrence exists. These findings are instrumental in designing a new state-dependent intermittent control to guide the cutting dynamics towards the safe basins. It is also seen that the state-dependent intermittent control is efficient in improving the cutting safety and shrinking the unsafe zones, even when the targeted basin for the control is larger than the real safe basin. (C) 2020 Elsevier B.V. All rights reserved. LA - English DB - MTMT ER - TY - JOUR AU - Liao, Xiaoping AU - Zhang, Zhenkun AU - Chen, Kai AU - Li, Kang AU - Ma, Junyan AU - Lu, Juan TI - Modified Mechanistic Model Based on Gaussian Process Adjusting Technique for Cutting Force Prediction in Micro-End Milling JF - MATHEMATICAL PROBLEMS IN ENGINEERING J2 - MATH PROBL ENG PY - 2019 PG - 12 SN - 1024-123X DO - 10.1155/2019/7468698 UR - https://m2.mtmt.hu/api/publication/31089926 ID - 31089926 AB - Micro-end milling is in common use of machining micro- and mesoscale products and is superior to other micro-machining processes in the manufacture of complex structures. Cutting force is the most direct factor reflecting the processing state, the change of which is related to the workpiece surface quality, tool wear and machine vibration, and so on, which indicates that it is important to analyze and predict cutting forces during machining process. In such problems, mechanistic models are frequently used for predicting machining forces and studying the effects of various process variables. However, these mechanistic models are derived based on various engineering assumptions and approximations (such as the slip-line field theory). As a result, the mechanistic models are generally less accurate. To accurately predict cutting forces, the paper proposes two modified mechanistic models, modified mechanistic models I and II. The modified mechanistic models are the integration of mathematical model based on Gaussian process (GP) adjustment model and mechanical model. Two different models have been validated on micro-end-milling experimental measurement. The mean absolute percentage errors of models I and II are 7.76% and 6.73%, respectively, while the original mechanistic model's is 15.14%. It is obvious that the modified models are in better agreement with experiment. And model II performs better between the two modified mechanistic models. LA - English DB - MTMT ER - TY - JOUR AU - Vourganti, Varun AU - Kandala, Shanti Swaroop AU - Meesala, Vamsi Chandra AU - Vyasarayani, C. P. TI - Supercritical and Subcritical Hopf Bifurcations in a Delay Differential Equation Model of a Heat Exchanger Tube Under Cross-Flow JF - JOURNAL OF COMPUTATIONAL AND NONLINEAR DYNAMICS J2 - J COMPUT NONLIN DYN VL - 1 PY - 2019 IS - 1 SP - 1 SN - 1555-1415 DO - 10.1115/1.4045635 UR - https://m2.mtmt.hu/api/publication/31008743 ID - 31008743 LA - English DB - MTMT ER -