TY - CHAP AU - Bachrathy, Dániel AU - Stépán, Gábor ED - Bernardini, D ED - Rega, G ED - Romeo, F TI - State dependent regenerative effect in milling processes T2 - Proceedings of the 7th European Nonlinear Dynamics Conference PB - Sapienza University of Rome CY - Rome SN - 9788890623424 PY - 2011 PG - 2 UR - https://m2.mtmt.hu/api/publication/1875898 ID - 1875898 LA - English DB - MTMT ER - TY - JOUR AU - Bachrathy, Dániel AU - Stépán, Gábor AU - Turi, János TI - State dependent regenerative effect in milling processes JF - JOURNAL OF COMPUTATIONAL AND NONLINEAR DYNAMICS J2 - J COMPUT NONLIN DYN VL - 6 PY - 2011 IS - 4 PG - 9 SN - 1555-1415 DO - 10.1115/1.4003624 UR - https://m2.mtmt.hu/api/publication/1875862 ID - 1875862 AB - The governing equation of milling processes is generalized with the help of accurate chip thickness derivation resulting in a state dependent delay model. This model is valid for large amplitude machine tool vibrations and uses accurate nonlinear screen functions describing the entrance and exit positions of the cutting edges of the milling tool relative to the workpiece. The periodic motions of this nonlinear system are calculated by a shooting method. The stability calculation is based on the linearization around these periodic solutions by means of the semidiscretization method applied for the corresponding time-periodic delay system. Predictor-corrector method is developed to continue the periodic solutions as the bifurcation parameter, that is, the axial immersion is varied. It is observed that the influence of the state dependent delay on linear stability can be significant close to resonance where large amplitude forced vibrations occur. The existence of an unusual fold bifurcation is shown where a kind of hysteresis phenomenon appears between two different stable periodic motions. LA - English DB - MTMT ER - TY - JOUR AU - Dombóvári, Zoltán AU - Barton, David AU - Wilson, Eddie AU - Stépán, Gábor TI - On the Global Dynamics of Chatter in the Orthogonal Cutting Model JF - INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS J2 - INT J NONLINEAR MECH VL - 46 PY - 2011 IS - 1 SP - 330 EP - 338 PG - 9 SN - 0020-7462 DO - 10.1016/j.ijnonlinmec.2010.09.016 UR - https://m2.mtmt.hu/api/publication/1454448 ID - 1454448 N1 - Funding Agency and Grant Number: Hungarian Scientific Research Foundation OTKAOrszagos Tudomanyos Kutatasi Alapprogramok (OTKA) [K68910]; HAS-BUTE Research Group on Dynamics of Machines and Vehicles Hungarian-Spanish Intergovernmental S&T Cooperation Programme [OMFB-01265/2007]; OPENAER project; Great Western Research fellowship; EPSRCEngineering & Physical Sciences Research Council (EPSRC) [EP/E055567/1] Funding text: Z D and G S were supported by the Hungarian Scientific Research Foundation OTKA Grant no K68910 HAS-BUTE Research Group on Dynamics of Machines and Vehicles Hungarian-Spanish Intergovernmental S&T Cooperation Programme Grant no OMFB-01265/2007 and the OPENAER project (CENIT program of CDTI) D A W B was supported by a Great Western Research fellowship R E W was supported by EPSRC Grant EP/E055567/1 Export Date: 28 November 2019 CODEN: IJNMA Export Date: 29 November 2019 CODEN: IJNMA AB - The large-amplitude motions of a one degree-of-freedom model of orthogonal cutting are analysed. The model takes the form of a delay differential equation which is non-smooth at the instant at which the tool loses contact with the workpiece, and which is coupled to an algebraic equation that stores the profile of the cut surface whilst the tool is not in contact. This system is approximated by a smooth delay differential equation without algebraic effects which is analysed with numerical continuation software. The grazing bifurcation that defines the onset of chattering motion is thus analysed as are secondary (period-doubling, etc.) bifurcations of chattering orbits, and convergence of the bifurcation diagrams is established in the vanishing limit of the smoothing parameters. The bifurcation diagrams of the smoothed system are then compared with initial value simulations of the full non-smooth delay differential algebraic equation. These simulations mostly validate the smoothing technique and show in detail how chaotic chattering dynamics emerge from the non-smooth bifurcations of periodic orbits. © 2010 Elsevier Ltd. All rights reserved. LA - English DB - MTMT ER - TY - JOUR AU - Bachrathy, Dániel AU - Insperger, Tamás AU - Stépán, Gábor TI - Surface properties of the machined workpiece for helical mills JF - MACHINING SCIENCE AND TECHNOLOGY J2 - MACH SCI TECHNOL VL - 13 PY - 2009 IS - 2 SP - 227 EP - 245 PG - 19 SN - 1091-0344 DO - 10.1080/10910340903012167 UR - https://m2.mtmt.hu/api/publication/1247389 ID - 1247389 N1 - Funding Agency and Grant Number: Hungarian Academy of SciencesHungarian Academy of Sciences; Hungarian Nation Sciences Foundation [OTKA K72911, OTKA K68910] Funding text: This research was supported in part by the Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences, and by the Hungarian Nation Sciences Foundation under grant no. OTKA K72911 and OTKA K68910. The authors also acknowledge with thanks the discussions and the useful comments of Dr. Martin Homer (University of Bristol). Export Date: 28 November 2019 CODEN: MSTEF AB - Stability and surface errors are investigated numerically for milling operations with a helical tool. A detailed two degree of freedom mechanical model is derived that includes both surface regeneration and the helical teeth of the tool. The governing delay-differential equation is analyzed by the semi-discretization method. The surface errors are predicted based on the (stable) forced motion of the tool. New surface error parameters were introduced to characterize the properties of the spatial machined surface. The errors were calculated numerically for a given machine tool and workpiece for different axial depths of cut and spindle speeds. It is shown that both good surface properties and large material removal rate can be achieved by appropriate axial immersion in case of helical fluted tool. This phenomenon was proved analytically by means of the Fourier transformation of the cutting force. LA - English DB - MTMT ER - TY - BOOK ED - Balachandran, Balakumar ED - Kalmár-Nagy, Tamás ED - Gilsinn, David TI - Delay Differential Equations: Recent Advances and New Directions PB - Springer Science+Business Media CY - New York, New York CY - Berlin CY - Heidelberg PY - 2009 SN - 9780387855950 DO - 10.1007/978-0-387-85595-0 UR - https://m2.mtmt.hu/api/publication/30178324 ID - 30178324 N1 - Table of contents: http://www.gbv.de/dms/bowker/toc/9780387855943.pdf Additional information: http://www.loc.gov/catdir/enhancements/fy1315/2008935618-d.html http://www.loc.gov/catdir/enhancements/fy1315/2008935618-t.html http://zbmath.org/?q=an:1162.34003 AB - Delay Differential Equations: Recent Advances and New Directions cohesively presents contributions from leading experts on the theory and applications of functional and delay differential equations (DDEs). Students and researchers will benefit from a unique focus on theory, symbolic, and numerical methods, which illustrate how the concepts described can be applied to practical systems ranging from automotive engines to remote control over the Internet. Comprehensive coverage of recent advances, analytical contributions, computational techniques, and illustrative examples of the application of current results drawn from biology, physics, mechanics, and control theory. Students, engineers and researchers from various scientific fields will find Delay Differential Equations: Recent Advances and New Directions a valuable reference. LA - English DB - MTMT ER - TY - JOUR AU - Insperger, Tamás AU - Stépán, Gábor AU - Turi, J TI - On the higher-order semi-discretizations for periodic delayed systems JF - JOURNAL OF SOUND AND VIBRATION J2 - J SOUND VIB VL - 313 PY - 2008 IS - 1-2 SP - 334 EP - 341 PG - 8 SN - 0022-460X DO - 10.1016/j.jsv.2007.11.040 UR - https://m2.mtmt.hu/api/publication/1148761 ID - 1148761 N1 - Export Date: 28 November 2019 CODEN: JSVIA AB - Semi-discretization techniques of periodic delayed systems are presented using zeroth-, first- and higher-order approximations of the delayed term. It is shown that if the time-periodic coefficients in the equation are approximated by piecewise constant functions, then there is no need to use higher than first-order approximations of the delayed term. The results are demonstrated on construction of the stability chart of the delayed Mathieu equation. (c) 2007 Elsevier Ltd. All rights reserved. LA - English DB - MTMT ER - TY - JOUR AU - Gradisek, J AU - Kalveram, M AU - Insperger, Tamás AU - Weinert, K AU - Stépán, Gábor AU - Govekar, E AU - Grabec, I TI - On stability prediction for milling JF - INTERNATIONAL JOURNAL OF MACHINE TOOLS & MANUFACTURE J2 - INT J MACH TOOL MANU VL - 45 PY - 2005 IS - 7-8 SP - 769 EP - 781 PG - 13 SN - 0890-6955 DO - 10.1016/j.ijmachtools.2004.11.015 UR - https://m2.mtmt.hu/api/publication/1148749 ID - 1148749 N1 - Megjegyzés-23771646 : Tamas/H-3748-2012 Export Date: 28 November 2019 CODEN: IMTME AB - Stability of 2-dof milling is investigated. Stability boundaries are predicted by the zeroth order approximation (ZOA) and the semi-discretization (SD) methods. While similar for high radial immersions, predictions of the two methods grow considerably different as radial immersion is decreased. The most prominent difference is an additional type of instability causing periodic chatter which is predicted only by the SD method. Experiments confirm predictions of the SD method, revealing three principal types of tool motion: periodic chatter-free, quasi-periodic chatter and periodic chatter, as well as some special chatter cases. Tool deflections recorded during each of these motion types are studied in detail. (c) 2004 Elsevier Ltd. All rights reserved. LA - English DB - MTMT ER - TY - JOUR AU - Hartung, Ferenc TI - Linearized stability in periodic functional differential equations with state-dependent delays JF - JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS J2 - J COMPUT APPL MATH VL - 174 PY - 2005 IS - 2 SP - 201 EP - 211 PG - 11 SN - 0377-0427 DO - 10.1016/j.cam.2004.04.006 UR - https://m2.mtmt.hu/api/publication/1332633 ID - 1332633 AB - In this paper, we study stability of periodic solutions of a class of nonlinear functional differential equations (FDEs) with stare-dependent delays using the method of linearization. We show that a periodic solution of the nonlinear FDE is exponentially stable, if the zero solution of an associated linear periodic linear homogeneous FDE is exponentially stable. LA - English DB - MTMT ER - TY - JOUR AU - Insperger, Tamás AU - Stépán, Gábor TI - Stability analysis of turning with periodic spindle speed modulation via semidiscretization JF - JOURNAL OF VIBRATION AND CONTROL J2 - J VIB CONTROL VL - 10 PY - 2004 IS - 12 SP - 1835 EP - 1855 PG - 21 SN - 1077-5463 DO - 10.1177/1077546304044891 UR - https://m2.mtmt.hu/api/publication/1148740 ID - 1148740 N1 - Megjegyzés-23771727 : Tamas/H-3748-2012 Megjegyzés-23771831 : Tamas/H-3748-2012 Export Date: 28 November 2019 CODEN: JVCOF AB - We investigate a single-degree-of-freedom model of turning with sinusoidal spindle speed modulation and the corresponding delay-differential equation with time-varying delay. The equation is analyzed by the numerical semidiscretization method. Stability charts and chatter frequencies are constructed. Improvement in the efficiency of machining is found for high modulation frequency and for low spindle speed domain. Period-one, period-two (flip), and secondary Hopf bifurcations were detected by eigenvalue analysis. LA - English DB - MTMT ER - TY - JOUR AU - Insperger, Tamás AU - Mann, BP AU - Stépán, Gábor AU - Bayly, PV TI - Stability of up-milling and down-milling, part 1: alternative analytical methods JF - INTERNATIONAL JOURNAL OF MACHINE TOOLS & MANUFACTURE J2 - INT J MACH TOOL MANU VL - 43 PY - 2003 IS - 1 SP - 25 EP - 34 PG - 10 SN - 0890-6955 DO - 10.1016/S0890-6955(02)00159-1 UR - https://m2.mtmt.hu/api/publication/1148736 ID - 1148736 N1 - Megjegyzés-23771652 : Tamas/H-3748-2012 Export Date: 28 November 2019 CODEN: IMTME AB - The dynamic stability of the milling process is investigated through a single degree of freedom mechanical model. Two alternative analytical methods are introduced, both based on finite dimensional discrete map representations of the governing time periodic delay-differential equation. Stability charts and chatter frequencies are determined for partial immersion up- and down-milling, and for full immersion milling operations. A special duality property of stability regions for up- and down-milling is shown and explained. (C) 2002 Elsevier Science Ltd. All rights reserved. LA - English DB - MTMT ER - TY - CHAP AU - Insperger, Tamás AU - Stépán, Gábor ED - Mook, D T ED - Balachandran, B TI - Semi-discretization of delayed dynamical systems T2 - 18th Biennial Conference on Mechanical Vibration and Noise PB - American Society of Mechanical Engineers (ASME) CY - New York, New York SN - 0791835316 T3 - Proceedings of the 2001 ASME Design Engineering Technical Conferences and Computers and Information in Engineering Conference Vol 6 A-C PY - 2001 SP - 1227 EP - 1232 PG - 6 UR - https://m2.mtmt.hu/api/publication/1148983 ID - 1148983 AB - An efficient numerical method is presented for the stability analysis of linear retarded dynamical systems. The method is based on a special kind of discretization technique with respect to the past effect only. The resulting approximate system is delayed and time-periodic in the same time, but still, it can be transformed analytically into a high dimensional linear discrete system. The method is especially efficient for time varying delayed systems, including the case when the time delay itself varies in time. The method is applied to determine the stability charts of the delayed Mathieu equation with damping. LA - English DB - MTMT ER - TY - BOOK AU - Stépán, Gábor TI - Retarded Dynamical Systems. Stability and Characteristic Functions TS - Stability and Characteristic Functions T3 - Pitman Research Notes in Mathematics Series ; 210. ET - 0 PB - Longman Scientific and Technical CY - Harlow PY - 1989 SP - 151 SN - 0470213353 UR - https://m2.mtmt.hu/api/publication/1002286 ID - 1002286 N1 - co-published: Wiley, New York LA - English DB - MTMT ER -