Relevant bibliographies by topics / Stability lobe

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  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
  6. Reports

Academic literature on the topic 'Stability lobe'

Author: Grafiati
Published: 4 June 2021
Last updated: 10 February 2022

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Journal articles on the topic "Stability lobe"

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Chen, Ming, Xiao Hui Zhang, and Wei Wei Ming. "Fuzzy Chatter Stability Lobes Model in Milling." Key Engineering Materials 443 (June 2010): 308–13. http://dx.doi.org/10.4028/www.scientific.net/kem.443.308.

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Based on the conventional chatter stability model, stability Lobes diagram in die & mould steel milling system is obtained. The derived diagram can be divided into two independent regions by a Lobes curve: absolutely stable and instable region. In fact, it is more reasonable that there should be a transition stage between the stable and instable state. That is to say, grade of stability (GOS) should be in a closed interval [0, 1], rather than Boolean logic. Due to the different stability sensibilities for different order Lobe curve in milling system, there should be different widths of transition belts for different order curve. Thus, with the help of Sigmoid transfer function widths of each order Lobe curve are studied. Finally, the fuzzy chatter stability is implemented by an adjustable slope coefficient.
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Batra, N. K., Gian Bhushan, and N. P. Mehta. "Effect of Load Orientation on the Performance of an Inverted Three-Lobe Pressure dam Bearing." Advanced Materials Research 365 (October 2011): 83–88. http://dx.doi.org/10.4028/www.scientific.net/amr.365.83.

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Sometimes the line of action of the load does not pass through the axis of a bearing and is shifted on either side by a few degrees. The effect of load orientation on the stability of an inverted three-lobe pressure dam bearing has been studied in this paper. An inverted three lobe pressure dam bearing is produced by incorporating two pressure dams in the upper two lobes and one relief track in the lower lobe. The result shows that stability of an inverted three-lobe pressure dam bearing supporting either rigid or flexible rotor is increased for the positive values of load orientation i.e. when the load line is shifted in the opposite direction of rotation.
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Corpus, William T., and William J. Endres. "Added Stability Lobes in Machining Processes That Exhibit Periodic Time Variation, Part 1: An Analytical Solution." Journal of Manufacturing Science and Engineering 126, no. 3 (August 1, 2004): 467–74. http://dx.doi.org/10.1115/1.1765137.

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An added family of stability lobes, which exists in addition to the traditional stability lobes, has been identified for the case of periodically time varying systems. An analytical solution of arbitrary order is presented that identifies and locates multiple added lobes. The stability limit solution is first derived for zero damping where a final closed-form symbolic result can be realized up to second order. The un-damped solution provides a mathematical description of the added lobes’ locations along the speed axis, an added-lobe numbering convention, and the asymptotes for the damped case. The derivation for the damped case permits a final closed-form symbolic result for first-order only; the second-order solution requires numerical evaluation. The easily computed analytical solution is shown to agree well with the results of the computationally intensive numerical simulation approach. An increase in solution order improves the agreement with numerical simulation; but, more importantly, it allows equivalently more added lobes to be predicted, including the second added lobe that cuts into the speed regime of the traditional high-speed stability peak.
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KĘCIK, KRZYSZTOF, RAFAŁ RUSINEK, and JERZY WARMIŃSKI. "STABILITY LOBES ANALYSIS OF NICKEL SUPERALLOYS MILLING." International Journal of Bifurcation and Chaos 21, no. 10 (October 2011): 2943–54. http://dx.doi.org/10.1142/s0218127411030258.

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In this paper, we study the stability of a high speed milling process of nickel superalloys Inconel 713C by methods used in nonlinear dynamics. Stability Lobe Diagram was a result of modal analysis and next verified by recurrence plots, recurrence quantification analysis and classical nonlinear methods. A stability lobes diagram shows the indistinct boundary between chatter-free stable machining and unstable processes. Nevertheless, some recurrence quantification analysis measures give interesting results.
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Oikonomou, Anastasia, Emanuelle Astrinakis, Ioannis Kotsianidis, Vassiliki Kaloutsi, Vassileios Didilis, Konstantinos Tsatalas, and Panos Prassopoulos. "Synchronous BALT Lymphoma and Squamous Cell Carcinoma of the Lung: Coincidence or Linkage?" Case Reports in Oncological Medicine 2013 (2013): 1–3. http://dx.doi.org/10.1155/2013/420393.

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A 72-year-old man presented with weight loss, fever, and malaise. Chest radiograph and CT revealed two large ill-defined masses in middle and left lower lobes. CT-guided biopsy of left lower lobe mass disclosed bronchus-associated lymphoid tissue (BALT) lymphoma. Middle lobe mass was considered second deposit in contralateral lung. The patient received chemotherapy for BALT. Followup CT disclosed regression of left lower lobe mass and stability of middle-lobe mass and of right paratracheal lymph nodes. CT-guided biopsy of middle-lobe mass revealed squamous cell lung carcinoma. Surgical biopsy of right paratracheal lymph nodes revealed malignancy. Disease was staged T3, N2, and M0. Combined chemotherapy for lung cancer and BALT lymphoma was initiated.
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Abele, E., and U. Fiedler. "Creating Stability Lobe Diagrams during Milling." CIRP Annals 53, no. 1 (2004): 309–12. http://dx.doi.org/10.1016/s0007-8506(07)60704-5.

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Hayati, Sajad, Mohammad Hajaliakbari, Yalda Rajabi, and Sajad Rasaee. "Chatter reduction in slender boring bar via a tunable holder with variable mass and stiffness." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 232, no. 12 (March 1, 2017): 2098–108. http://dx.doi.org/10.1177/0954405417690554.

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In this study, a new strategy is presented to increase the machining stability due to chatter suppression for boring and turning machining processes. The proposed approach is based on varying the position of stability lobes via changing mechanical properties of the tool body such as the mass and stiffness. Because of the shape of stability lobe diagrams, having a tool with a tunable stability lobe diagram can be useful to alter an unstable condition to a stable condition. For this purpose, a structure for the tool body is designed that is consisted of a hollow body with a core as a tunable screw inside it. As the core gets in or out, it changes the mass and stiffness of the tool body that leads to change the position of stability lobe diagram. In order to study the effect of designed structure on stability, the structure is simulated using a validated finite element time domain model. The time domain simulation shows a considerable improvement in stability of process. The strategy is experimentally applied to the process via modulation of the tool structure in the machining process to validate the simulation results. The experimental results have a high coincidence with theory and show a good improvement in stability.
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Harrison, A. J. L., and T. R. A. Pearce. "Prediction of lobe growth and decay in centreless grinding based on geometric considerations." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 216, no. 9 (September 1, 2002): 1201–16. http://dx.doi.org/10.1243/095440502760291763.

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The growth and decay of lobes during centreless grinding have been studied by previous researchers using physical tests, time-domain simulation and identification of the roots of the Laplace transform of the characteristic equation. In this paper, the authors have extended these latter two methods to generate complete stability diagrams encompassing the entire practical range of machine set-up angles. These diagrams indicate that by varying the set-up angles in a prescribed manner during grinding, rapid rounding of arbitrarily lobed components can be achieved. This is verified via time-domain simulation. Secondly, a novel and arguably more intuitive method of predicting the lobe growth and decay during centreless grinding is presented. The method considers the locations of the three points of contact between a lobed workpiece and the regulating wheel, the support plate and the grinding wheel. Axial symmetry is assumed. A unique circle can be drawn through these three points. The centre and radius of this circle vary continually as the workpiece rotates, in a manner dependent upon the workpiece's profile and the set-up angles. An above-average instantaneous radius leads, via machine stiffness, to a correspondingly larger grinding force and so to an increased instantaneous depth of cut. If this occurs when the trough of a lobe is being ground, the trough will become deeper and lobe growth will result. By contrast, if the instantaneous radius is below average when the trough is being ground, the lobe will decay. From this simple geometric consideration, the authors have calculated the rates of decay and growth of a range of numbers of lobes, across a wide range of set-up angles. The results are shown to agree well with those given using the previous methods.
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Rao, TVVLN, Ahmad M. A Rani, Norani M. Mohamed, Hamdan H. Ya, Mokhtar Awang, and Fakhruldin M Hashim. "Static and stability analysis of partial slip texture multi-lobe journal bearings." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 234, no. 4 (October 17, 2019): 567–87. http://dx.doi.org/10.1177/1350650119882834.

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This paper presents one-dimensional analysis of modified dynamic Reynolds equation derived for partial slip texture multi-lobe journal bearings. The novelty included in this study is the configuration of partial slip texture region on the bottom bearing lobe surface of a multi-lobe journal bearing under a constant vertical load. The nondimensional pressure and shear stress for steady-state and nondimensional pressure gradients for dynamic coefficients for each lobe with partial slip texture configuration are derived based on narrow groove theory. Linearized stability analysis is evaluated using infinitesimal perturbation method. Results of static and stability characteristics of partial slip texture multi-lobe (two-axial groove, elliptical, three-lobe and offset) journal bearings are presented. Partial slip texture configuration significantly enhances load capacity, coefficient of friction, and stability of two-lobe journal bearing.
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Li, Hong Kun, and Peng Shi Zhao. "Milling Stability Lobe Diagram Construction on FV520B Stainless Steel and Experimental Testing Investigation." Applied Mechanics and Materials 437 (October 2013): 586–89. http://dx.doi.org/10.4028/www.scientific.net/amm.437.586.

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This paper investigates the zero-order analytical method to construct milling stability lobe diagram to improve the impeller milling efficiency. It is used to determine FV520B material milling parameters optimization. This method can select the appropriate number of revolutions and the cutting depth processing avoiding chatter occurrence. It can keep the required accuracy and surface quality for the workpiece. At the same time, it improves the safety of the tool and machine reliability. Through experiments data analysis, parameters constructing lobe diagram can be obtained. Different testing points in the constructed lobes are used to verify the correctness of the method. The results show that this method has great significance in the actual impellers manufacturing process.
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Dissertations / Theses on the topic "Stability lobe"

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Fiala, Zdeněk. "Vibrace při obrábění kovů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229045.

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The diploma work deals with a mathematical description of vibration and its generation when machining. Moreover, some techniques of modal parameters measurement in the theoretical part are included. The practical part is designed and based on the measured natural frequencies of the machine with specific tool and materials. In conclusion, a lobe diagram stability for semiautomatic lathe SPN 12 CNC and selected machining operation is specified by means of apparatus.
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Tavakoli, Aydin. "Cadherin involvement in axonal branch stability in the Xenopus retinotectal system." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=112312.

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Retinal ganglion cell (RGC) axon arbors within the optic tectum are refined in development through a dynamic process of activity-dependent remodeling. The synaptic adhesion molecule N-cadherin is a candidate for mediating selective stabilization and elaboration of RGC axons due to its localization to perisynaptic sites and its modifiability by neural activity. RGCs of Xenopus tadpoles were co-transfected with plasmids encoding a dominant negative N-cadherin (N-cadDeltaE) and eGFP or eYFP. Using two-photon in vivo time-lapse imaging, we found that axons expressing N-cadDeltaE became less elaborate than controls over three days of daily live imaging. Shorter interval time-lapse imaging of axons expressing synaptophysin-GFP to visualize putative synaptic sites revealed that N-cadDeltaE expressing axons form fewer stable branches than controls and that stabilization of axonal branches at synaptic sites is altered. We conclude that N-cadherin participates in the stabilization of axonal branches in the Xenopus retinotectal system.
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Sismilich, Vladimír. "Vibrace při obrábění kovů – příčiny a jejich eliminace." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229329.

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This diploma thesis is concerning about summarizing and describing types of vibrations, their causes and influences to the machining. The stable conditions of machining were pointed out. The experiment was conducted in which the frequency response function of specific milling machine was measured. Than the stability lobe diagram was constructed.
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Sedlář, Jiří. "Konstrukce dvouosého suportu vícevřetenového soustružnického automatu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-443158.

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This diploma thesis deals with the design of a two-axis multi-spindle lathe carriage. In the first part, there is made a research, and its aim is to find possible variants of design solutions. After the best rated variant was selected, the thesis further continues with the necessary technical calculations of the main design nodes such as a synchronous servomotor, ball screw, linear guide and bearing. The design itself was carried out with regard to calculations and the resulting model was examined in terms of dynamic stability. The subject of examination was to find the natural frequencies of the assembly and to determine the amplitudes of the oscillations which arise from the harmonic excitation force. Finally, Lobe diagrams for grooving and longitudinal turning operations were drawn.
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Montalban, Laura. "Evaluation of a Contactless Excitation and Response System (CERS) for process planning applications : An experimental study." Thesis, KTH, Industriell produktion, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-192679.

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Chatter vibration is a common problem for the manufacturing industry that limits the productivity, accuracy and surface quality of machined parts. This study is focused on the out of process methods, such as Stability Lobe Diagrams (SLD), that ensure the selection of the optimal cutting parameters in which the machining process is stable. Previous studies have found that the dynamic properties of the spindle change with the rotational speed. This fact can also affect the accuracy of the SLD predictions, since, the traditional structural dynamic tests such as the Experimental Modal Analysis (EMA) are carried out at static state. An alternative method for the calculation of speed - dependant SLD using a Contactless Excitation Response System (CERS) was proposed. The modal characteristics, such as natural frequencies and damping ratio were determined by EMA tests carried out at idle state whereas CERS measurements were performed at increasing rotational speeds up to 14000 rpm. Subsequently, the SLD at static and dynamic state were computed. Finally, it was concluded that there was not a significant variation of the dynamic properties and SLD prediction with spindle speed at the tested speed range (0 rev/min to 14000 rev/min).
Chatter är ett vanligt problem inom tillverkningsindustrin som begränsar produktiviteten och minskar noggrannheten och kvalitén på bearbetade ytor. Denna studie fokuserar på processkilda metoder, till exempel stabilitetsdiagram (SLD), vilka säkerställer valet av optimala skärparametrar för en stabil skärprocess. Tidigare studier har visat att spindelns dynamiska egenskaper är beroende av rotationshastigheten. Detta påverkar även noggrannheten vid skattningen av SLD eftersom traditionella strukturdynamiska tester, som experimentell modalanalys (EMA), utförs under statiskt tillstånd. En alternativ metod för bestämning av hastighetsberoende SLD med hjälp av ett beröringsfritt excitering- och svarssystem (CERS) föreslås. De modala egenskaperna, som till exempel egenfrekvens och dämpning, bestämdes med hjälp av EMA med stillastående spindel medan mätningar med CERS utfördes med ökad rotationshastighet upp till 14000 varv/min. Efter detta beräknades SLD för de båda fallen. Till sist drogs slutsatsen att testerna inte påvisade någon större skillnad, vare sig dynamiska egenskaper eller SLD skattning, för spindelhastigheter inom det testade intervallet (0 till 14000 varv/min).
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Cvijetin, Mlađenović. "Dinamičko ponašanje obradnih sistema za mikroobradu." Phd thesis, Univerzitet u Novom Sadu, Fakultet tehničkih nauka u Novom Sadu, 2020. https://www.cris.uns.ac.rs/record.jsf?recordId=114858&source=NDLTD&language=en.

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Predmet istraživanja prikazanih u okviru doktorske diseracije su samopobudne vibracije pri obradi glodanjem. Na osnovu detaljne analize zakonitosti nastanka samopobudnih vibracija uspostavljena je određena paralela između glodanja i mikrogkodanja, za slučajeve kada je dubina rezanja veća od radijusa rezne ivice alata. Za tako usvojene pretpostavke, razvijeni su modeli unapređene numeričke simulacije procesa glodanja i mikroglodanja. Razvijeni modeli su svestrano verifikovani, s jedne strane, u segmentima gde postoje podaci u literaturi; poređenjem sa rezultatima drugih autora, a sa druge strane poređenjem sa sopstvenim eksperimentalnim ispitivanjima. Za eksperimentalno definisanje granične dubine rezanja pri glodanju predložena je inovativna metoda tangenti, a pri mikroglodanju, imajući u vidu raspoloživu mernu opremu, metoda hrapavosti obrađene površine. Matematički modeli i eksperimentalne metode su verifikovani pri obradi tri karakteristične vrste materijala i na dva obradna sistema pri glodanju, odnosno jednom materijalu i jednom obradnom sistemu pri mikroglodanju. Rezultati istraživanja su prezentovani kroz dvanaest poglavlja čiji sadržaj se navodi u nastavku.U prvom, uvodnom poglavlju, ukazano je na značaj istraživanja samopobudnih vibracija pri makro i mikroglodanju. Prikazana je i aktuelnost istraživanja analizom broja naučnih radova koji se bave problematikom samopobudnih vibracija u periodu od poslednjih dvadeset pet godina.Kroz drugo poglavlje detaljno su prikazana dosadašnja istraživanja samopobudnih vibracija pri makroglodanju, dok su u trećem poglavlju prikazana istraživanja samopobudnih vibracija pri mikroglodanju. Izvršena je analiza uticajnih parametri na graničnu dubinu rezanja, koja predstavlja osnovni pokazatelj dinamičke stabilnosti kako makro, tako i mikroobradnih sistema.Na osnovu saznanja prikazanih u okviru drugog i trećeg poglavlja u četvrtom poglavlju su definisani ciljevi i hipoteze istraživanja.Matematičke metode za definisanje karte stabilnosti obradnog sistema, prikazane su u petom poglavlju. Prikazana su dva matematička modela za definisanje karte stabilnosti pri makroglodanju, model srednjeg ugla kontakta alata u zahvatu i model Furijeovih redova. Prezentovana je numerička simulacija procesa obrade glodanjem, namenjena prvenstveno za simulaciju sila rezanja. Polazeći od prethodno prikazane ideje u okviru ovog poglavlja je razvijena nova matematička metoda predikcije granične dubine rezanja - unapređena numerička simulacija procesa glodanja.U okviru šestog poglavlja prikazane su eksperimentalne metode identifikacije vibracija mašina alatki, odnosno eksperimentalno određivanje modalnih parametara obradnih sistema kao i metode detekcije samopobudnih vibracija pri glodanju. U cilju definisanja granične dubine rezanja, prikazana je metoda frekventne analize vibracija pri glodanju, kao metoda koja se često koristi u savremenim eksperimentalnim istraživanjima. Međutim, i matematičke i eksperimentalne metode analize vibracija pri glodanju imaju određena ograničenja. Polazeći od prethodnog, razvijena je inovativna metoda tangenti, bazirana na ranije korišćenoj metodi u okviru Laboratorije za mašine alatke Instituta za proizvodno mašinstvo FTN u Novom Sadu, i primeni savremenih mernih sistema. Pored toga, u ovom poglavlju je eksperimentalno potvrđen uticaj samopobudnih vibracija na kvalitet obrađene površine i geometrijsku tačnost obratka.Metodologija sprezanja matematički i eksperimentalno definisanih funkcija frekventnog odziva elemenata mašine alatke prikazana je u sedmom poglavlju. Prezentovane su jednačine sprezanja pomerajnih odziva matematmički definisanih funkcija frekventnog odziva alata i držača alata, bazirane na Ojlerovoj teoriji grede, sa eksperimentalno definisanom funkcijom frekventnog odziva sklopa glavnog vretena mašine alatke.U okviru osmog poglavlja razvijen je matematički model sila rezanja pri mikroglodanju. Predloženi model sila rezanja, koji uzima u obzir silu trenja između leđne površine alata i obrađene površine, implementiran je u unapređenu numeričku simulaciju glodanja čime je omogućena njena primena za definisanje graničnih dubina rezanja pri mikroglodanju.Verifikacija razvijenih numeričkih i eksperimentalnih metoda za ispitivanje vibracija pri makroglodanju je prikazana u devetom poglavlju. Sproveden je niz eksperimentalnih ispitivanja, pri kojima su određivane granične dubine glodanja pri obradi tri različita materijala obratka (Al7075, 42CrMo4 i Ti-6Al-4V) na dva obradna sistema. Na osnovu ovih ispitivanjima izvršena je verifikacija unapređene numeričke simulacije glodanja i inovativne metode tangenti.U desetom poglavlju prikazana je verifikacija metoda analize samopobudnih vibracija pri mikroglodanju. Primenom metodologije sprezanja pomerajnih odziva, definisani su modalni parametri obradnog sistema za mikroobradu, potrebni za definisanje graničnih dubina rezanja, tj. karte stabilnosti, unapređenom numeričkom simulacijom mikroglodanja. Karta stabilnosti definisana razvijenom unapređenom numeričkom simulacijom, verifikovana je eksperimentalno i poređenjem sa literaturnim izvorima.U jedanaestom poglavlju data su zaključna razmatranja, kritički osvrt na ostvarene rezultate, i pravci budućih istraživanja.Dvanaesto poglavlje prikazuje pregled korišćene literature, koju čini 218 referenci većim delom citirane u samom radu, a u zasebnom poglavlju dati su prilozi.
The subject of research presented in the doctoral dissertation are self-excited vibrations in milling. Based on a detailed analysis of the self-excited vibrations occurrence, a certain parallel has been established between macro and micromilling, for cases when the depth of cut is greater than the cutting edge radius of the tool. For such adopted assumptions, models of advanced numerical simulation of macro and micromilling processes were developed. The developed models were comprehensively verified, on the one hand, by comparison with the results of other authors, and on the other hand by comparison with own experimental results. An innovative tangent method has been proposed for the experimental definition of the cutting depth limit in milling, and the method of machined surface roughness has been proposed for micromilling, having in mind the available measuring equipment. Mathematical models and experimental methods were verified by machining three characteristic types of materials on two machining systems in macromilling, and one material on one machining system in micromilling. The results of the research are presented through twelve chapters, the content of which is listed below.In the first, introductory chapter, the importance of the research of self - excited vibrations in macro and micromilling is pointed out. The topicality of the research is also presented by analyzing the number of scientific papers dealing with the issue of self - excited vibrations in the period of the last twenty - five years.The second chapter presents in detail the previous research on self-excited vibrations during macromilling, while the third chapter presents research on self-excited vibrations during micromilling. An analysis of the influential parameters on the cutting depth limit was performed, which is a basic indicator of the dynamic stability of both macro and micromachining systems.Based on the findings presented in the second and third chapters, the fourth chapter defines the goals and hypotheses of the research.Mathematical methods for defining the stability lobe diagram of the machining system are presented in the fifth chapter. Two mathematical models for defining the stability lobe diagram for macromachining are presented, the model of the tool’s mean contact angle and the model of Fourier series. Numerical simulation of the milling process is presented, intended primarily for the simulation of cutting forces. Starting from the previously presented idea, a new mathematical method for predicting the cutting depth limit has been developed within this chapter - an improved numerical simulation of the milling process.In the sixth chapter, experimental methods of machine tools vibration identification are presented, ie experimental determination of machining systems modal parameters as well as methods of self - excited vibrations detection during milling. In order to define the cutting depth limit, the method of vibrations frequency analysis during milling is presented, as a method that is often used in modern experimental research. However, both mathematical and experimental methods of milling vibration analysis have certain limitations. Starting from the previous one, an innovative tangent method was developed, based on the previously developed method, used within the Laboratory for Machine Tools, Institute of Production Engineering Facultz of Technical Sciences in Novi Sad, and the application of modern measuring systems. In addition, in this chapter, the influence of self - excited vibrations on the machined surface quality and the geometric accuracy of the workpiece is experimentally confirmed.The methodology of machine tool elements mathematically and experimentally defined frequency response functions coupling is presented in the seventh chapter. The displacement responses coupling equations of mathematically defined tools and tool holders FRF's (based on Euler 's beam theory) with the experimentally defined FRF of the machine tool main spindle assembly are presented.Within the eighth chapter, a mathematical model of cutting forces in micromilling was developed. The proposed cutting forces model, which takes into account the friction force between the reliefe tool surface and the machined surface, is implemented in an advanced numerical micromilling simulation, which enables its application to define cutting depth limit in micromilling.Verification of the developed numerical and experimental methods for vibrations analysis during macromachining is presented in the ninth chapter. A series of experimental tests were performed, during which the cutting depth limits were determined during the milling of three different workpiece materials (Al7075, 42CrMo4 and Ti-6Al-4V) on two machining systems.In the tenth chapter, the verification of the methods of analysis of self-excited vibrations during micromilling is presented. Using the methodology of coupling displacement responses, the modal parameters of the machining system for micromachining are defined, needed to define the cutting depth limits, ie. stability lobe diagram, by advanced numerical micromilling simulation The stability lobe diagram, defined by the developed advanced numerical simulation, was verified experimentally and by comparison with literature sources.The eleventh chapter provides concluding remarks, a critical review of the achieved results, and directions for future research.The twelfth chapter presents an overview of the used literature, which consists of 218 references, mostly cited in the paper itself.
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Quintana, i. Badosa Guillem. "Stability lobes diagram identification and surface roughness monitoring in milling processes." Doctoral thesis, Universitat de Girona, 2010. http://hdl.handle.net/10803/7769.

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La millora de la productivitat i la qualitat són indubtablement dues de les principals exigències del sector productiu modern i factors clau per la competitivitat i la supervivència. Dins aquest sector,la fabricació per arrancada de material juga encara avui en dia un paper protagonista tot i l'aparició de noves tècniques de conformat per addició.Indústries com l'aeronàutica, l'automobilística,la del motlle o l'energètica, depenen en bona part de les prestacions de les màquines-eina. Aquesta Tesi aborda dos aspectes rellevants quan es tracta de millorar de la productivitat i la qualitat del sector productiu: el problema del fimbrament, més conegut per la denominació anglosaxona chatter,i la monitorització de la rugositat superficial en el mecanitzat a alta velocitat.
Productivity and quality improvement are undoubtedly two of the main demands of the
modern manufacturing sector and key factors for competitiveness and survival. Within this sector, material removal processes play, still nowadays, a principal role despite the emergence of additive manufacturing techniques. Industries such as aerospace, automotive, molds and dies or energy largely depend on machine tools performance for improved productivity and quality. This Thesis is focused on two important aspects when it comes to improving productivity and quality of the manufacturing sector: chatter problem, and surface roughness monitoring in high speed milling.
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Iglesias, Alex. "Milling stability improvement through novel prediction and suppression techniques." Doctoral thesis, Universitat de Girona, 2016. http://hdl.handle.net/10803/392143.

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Chatter is one of the major problems in today’s milling processes. Theoretical models to calculate stability lobes are used to predict and avoid chatter onset. However, current predictions are not accurate enough and significant deviations between predicted and experimentally observed stability limits have been reported.The causes for these deviations are diverse and can be the result of the sum of multiple effects. According to previous works, main errors in stability prediction are related to lack of knowledge about double period instability (flip lobes) and inappropriate determination of dynamic parameters through standard experimental characterization techniques. This Thesis deals with these two problems that affect accurate chatter prediction, contributing with new knowledge and calculation methods for double period type lobes and developing a new methodology for a more accurate dynamic response identification. Nevertheless, an accurate chatter stability prediction does not necessarily imply an optimum use of the machine to maximize productivity, as it is required in current production environments. For this reason, three novel process stabilization techniques are proposed for those cases in which the designed machining process is subject to chatter vibrations.
El chatter és avui en dia un dels principals problemes en els processos de fresat. Per predir i evitar la seva aparició es disposa de models teòrics per al càlcul dels lòbuls d'estabilitat. No obstant això, les prediccions realitzades amb els models d'estabilitat de fresat no són robustes, presentant casos en què les desviacions entre la predicció i la realitat són importants. Les causes d'aquestes desviacions són variades i poden ser degudes a la suma de múltiples efectes. A la vista dels estudis previs realitzats, els principals errors es troben en l'omissió de lòbuls de doble període (lòbuls flip) i errors en la determinació experimental dels paràmetres dinàmics del sistema mitjançant mètodes tradicionals. Aquesta Tesi aborda aquests dos problemes principals en la predicció, aportant nous coneixements sobre el chatter de doble període i desenvolupant una nova metodologia per a un càlcul més precís de la resposta dinàmica del sistema. No obstant això, una predicció precisa de les condicions que donen lloc a un procés de fresat estable no garanteix l'aprofitament òptim de la màquina per maximitzar la productivitat, tal com s'exigeix en l'entorn productiu actual. Per això, es proposen tres noves tècniques per a l'eliminació de chatter en aquells casos en què, el procés de mecanitzat dissenyat estigui sota el perillós influx del chatter.
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Malý, Pavel. "Výpočtové modelování samobuzeného kmitání při obrábění." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-320178.

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Diplomová práce se zabývá analýzou produktivity a efektivity řezného procesu frézování. Pro zjištění kritické hloubky třísky byla analyzována reálná frézka. Model frézky byl vytvořen v programu Autodesk Inventor. Analýza řezného procesu probíhala v programu Ansys Workbench. Výsledky byly použity pro sestavení stabilitních diagramů. Po vyhodnocení výsledků byly navrženy dva přístupy pro zefektivnění procesu frézování. Vliv těchto změn na produktivitu řezného procesu byl ověřen porovnáním výsledků s předchozí analýzou.
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Sebastien, Nyamien Yahaut. "Fenômenos climatológicos e hidrológicos e sua repercussão sobre a limnologia dos reservatórios de Barra Bonita-SP, Carlos Botelho (Lobo-Broa)-SP e Tucuruí-PA-Brasil." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/18/18139/tde-12092016-101226/.

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Os reservatórios, ao longo do tempo, passaram de simples controle de enchente para a produção de energia elétrica e, nos últimos anos, para um uso múltiplo. Em todos os casos, a qualidade é de suma importância. Nesta pesquisa, propõe-se analisar a resposta dos reservatórios de Barra Bonita e Carlos Botelho (Lobo-Broa) no estado de São Paulo, nas latitudes de 22º31\' S e 22º15\' S respectivamente e o de Tucuruí no estado do Pará a 3º45\' S aos diferentes fatores climatológicos, hidrológicos e limnológicos. Dados limnológicos, climatológicos, hidrológicos, imagens de satélites, foram obtidos de fontes diversas. Calcularam-se os parâmetros morfométricos, características físicas como conteúdo de calor, trabalho de vento, resistência térmica à circulação, os números adimensionais de Wedderburn, Richardson, Froude e Lake Number, as variâncias, as correlações e regressões entre os diferentes parâmetros. Observou-se que os reservatórios de Barra Bonita e Broa considerados rasos são sensíveis aos fatores climatológicos e Tucuruí aos fatores hidrológicos e infiltrações. O Broa e Barra Bonita passam por instabilidade quando a estação passa de outono para inverno e da primavera para o verão. Com relação aos nutrientes, na Barra Bonita, o fosfato total (PO4), amônia (NH4) e nitrato (NO3) tiveram correlações positivas com o conteúdo de calor, trabalho de vento e a resistência térmica a circulação. As correlações não foram significativas com a estabilidade mostrando que quanto maior a estabilidade, menos disponível se tornam os compostos. No Broa as correlações positivas foram observadas entre a estabilidade e o silicato, o nitrito. Então há maior disponibilidade de nutriente (fosfato total, nitrato, amônia) no período de instabilidade. Como resposta na Barra Bonita observa-se o desenvolvimento dos Bacillariophyceae (Aulacoseira italica e Aulacoseira granulate) durante as instabilidades. No período de inverno e verão, diminui os Bacillariophyceae conseqüência de uma diminuição de nutrientes e um desenvolvimento de Chlorophyceae. Enquanto isso no Broa, durante o período de estabilidade, são disponibilizados a sílica (Si) e o nitrito (NO2), reduzindo o PO4, a (NH4) e o NO3. As estabilidades das UHE de Barra Bonita e Carlos Botelho localizada no sudeste do Brasil ocorrem no verão enquanto que de Tucuruí muda de estado nos períodos de chuva e estiagem. Com estas mudanças de estado, ocorre uma sucessão de comunidade planctônica e um aumento dos custos de tratamento de água.
Reservoir uses have evolved from simple control of inundation to a vast gamut of multiple uses. In all reservoirs, at present, control of water quality as well as water quantity is a fundamental need. Responses of reservoirs related to water quality and quantity are dependent upon climatological and hydrological cycles as forcing functions. The objective of this research was to analyze the impact of climatological and hydrological factors on the limnology and productivity of reservoirs. For this research three reservoirs were selected : Barra Bonita (Lat 22º31\' S/Long 48º33\' W), Carlos Botelho (Lobo-Broa) (Lat 22º15\' S/Long 47º49\' W) and Tucuruí reservoir (Lat 3º45\'03\'\' S/Long 49º40\'03\'\' W). Morphometric parameters, physical factors : heat content, thermal resistance to circulation and non dimensional numbers such as Wedderburn, Richardson, Lake Number and Froude were calculated. Statistic analyses : variance, regression and correlation coefficient were also determined. The data on climatology, hydrology and limnology were obtained from published papers, thesis and dissertations available. The results show that shallow reservoirs such as Barra Bonita and Carlos Botelho (12 m average depth and 3.2 m average depth respectively) were affected by climatic factors such as air temperature, wind and effects of cold fronts. Tucuruí reservoir, deeper and located at low latitude is influenced by hidrologic factors such as rainfall, river flow, drainage water. The response of the reservoir is shown by the frequency of stability/mixing patterns. When there is circulation, such as in Barra Bonita and Carlos Botelho (Lobo/Broa) reservoirs, nutrients availability increases. Both in Barra Bonita and Carlos Botelho reservoirs mixing patterns increase the presence of diatoms in the water column (Aulacoseira italica for Carlos Botelho reservoir and Aulacoseira italica and Aulacoseira granulata for Barra Bonita reservoir). When stability occurs, Cyanophyta will develop its blooms specially in Barra Bonita, a eutrophic reservoir. The stability for both reservoirs located in the Southeast of Brazil occurs during the summer. Tucuruí reservoir change states during the year, specially during the periods of high and low rainfall corresponding to high and low water discharge. With the impact of the mixing, processes that promote changes in the vertical structure of the reservoir water quality increases the costs of treatment. Thus, the successive pulses that changes community succession (planktonic community) in the reservoirs are a consequence of external forces, climatological or hydrological or both.
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Books on the topic "Stability lobe"

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Peace, United States United States Institute of. Where is the Lone Ranger when we need him?: America's search for a postconflict stability force. Washington, D.C: United States Institute of Peace Press, 2004.

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Where is the Lone Ranger when we need him?: America's search for a postconflict stability force. Washington, D.C: United States Institute of Peace Press, 2003.

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Guerard, Dale A. An investigation into the factors that influence intimacy ratings and love style for individuals in romantic relationships: Sex-typology, proximal distance and current relationship stability. Sudbury, Ont: Laurentian University, Department of Psychology, 1997.

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DesMaisons, Kathleen. Potatoes not prozac: A natural seven-step dietary plan to stabilize the level of sugar in your blood, control your cravings and lose weight, and recognize how foods affect the way you feel. New York: Simon & Schuster, 1998.

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Potatoes not prozac: A natural seven-step dietary plan to control your cravings and lose weight, recognize how foods affect the way you feel, and stabilize the level of sugar in your blood. New York, NY: Simon & Schuster, 1999.

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DesMaisons, Kathleen. Potatoes not prozac: A natural seven-step dietary plan to stabilize the level of sugar in your blood, control your cravings and lose weight, and recognize how foods affect the way you feel. New York: Simon & Schuster, 1998.

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Where Is The Lone Ranger Americas Search For A Stability Force. NBN INTERNATIONAL, 2013.

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Perito, Robert M. Where Is the Lone Ranger When We Need Him?: America's Search for a Postconflict Stability Force. United States Institute of Peace Press, 2004.

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Carrington, Tyler. Love at Last Sight. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780190917760.001.0001.

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Love at Last Sight is a history of dating in the modern metropolis. It opens with the seemingly simple question, “How did single people meet and fall in love in new big cities like Berlin at the turn of the century?” but what emerges from this investigation of daily newspapers, diaries, serial novels, advice literature, police records, and court cases is a world of dating and relationships that was anything but simple. The murder of Frieda Kliem, a young, enterprising seamstress who was using newspaper personal ads to find a husband—the story of which serves as the book’s central narrative—reveals the tremendous risk associated with modern approaches to love and dating. The risk of fraud, censure, or worse was ever present, especially for the many Berliners who strove for the stability of middle-class life but were outsiders to the social power structures of German society. Indeed, though the technologies and opportunities of the big city offered the best shot at finding love or intimate connection among the urban sea of strangers, availing oneself of them—pursuing a missed connection from the streetcar or using a newspaper personal ad—meant putting one’s livelihood, respectability, and life on the line. This was the romantic dilemma facing the vast majority of city dwellers at the turn of the century, and a great many chose to risk everything for some measure of connection and intimacy. This book explores their stories as a way of illuminating this core tension of modern, metropolitan life.
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Schmeink, Lars. Science, Family, and the Monstrous Progeny. Liverpool University Press, 2017. http://dx.doi.org/10.5949/liverpool/9781781383766.003.0004.

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Chapter 4 reflects on the creation of the posthuman, concentrating on the genetic manufacture of life in Vincenzo Natali's film Splice (2009). In shifting the medium of the discussion, the more private perspectives of posthuman creation and especially the creature itself are foregrounded by foregoing the larger, social discussion of the consequences provided in chapter 3. Instead, the chapter analyzes liquid modern realities and the loss of stability in its personal dimension, such as love, sex, and procreation. The film, as a biopunk adaptation of the classic Frankenstein-story, makes elaborate use of the metaphor of the monstrous to characterize contemporary society and its desire to liquefy personal bonds and relations. The posthuman becomes monstrous allegory for the liquid modern wish to forego social commitment, especially and most frighteningly reflected in concepts of love and motherhood, where the film warns about the interpersonal consequences of relegating procreation to science and extracting it from stable, secure social relations.
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Book chapters on the topic "Stability lobe"

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Großmann, K., and M. Löser. "Synthesis of Stability Lobe Diagrams." In Lecture Notes in Production Engineering, 225–44. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-32448-2_10.

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Zhang, Mingkai, Xiaowei Tang, Rong Yan, Fangyu Peng, Chen Chen, Yuting Li, and Haohao Zeng. "A Boundary Auto-Location Algorithm for the Prediction of Milling Stability Lobe Diagram." In Intelligent Robotics and Applications, 299–308. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-97586-3_27.

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Azoui, Cherifa, and Brahim Benmohammed. "Stability Lobes for 1DOF and 2DOF Milling System." In Design and Modeling of Mechanical Systems - II, 645–50. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-17527-0_64.

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Baklouti, Wael, Charfeddine Mrad, and Rachid Nasri. "Numerical Determination of Cutting Stability Lobes in Orthogonal Milling." In Lecture Notes in Mechanical Engineering, 392–98. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-27146-6_42.

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Davis, Keith E. "What Attachment Styles and Love Styles Add to the Understanding of Relationship Commitment and Stability." In Handbook of Interpersonal Commitment and Relationship Stability, 221–37. Boston, MA: Springer US, 1999. http://dx.doi.org/10.1007/978-1-4615-4773-0_13.

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Arnaud, L., and G. Dessein. "Application of the Stability Lobes Theory to Milling of Thin Workpieces." In Recent Advances in Integrated Design and Manufacturing in Mechanical Engineering, 271–80. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-017-0161-7_27.

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Yılmaz, Hasan, and Ender Cigeroglu. "Effect of Spin Speed on Stability Lobes in High Speed Machining." In Topics in Modal Analysis, Volume 7, 407–14. New York, NY: Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-6585-0_38.

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Witt, Frank H. "Strukturbildung und Strukturwandel: Stabilität, lose Kopplung, Redundanz und Lernen." In Theorietraditionen der betriebswirtschaftlichen Forschung, 203–11. Wiesbaden: Gabler Verlag, 1995. http://dx.doi.org/10.1007/978-3-322-86563-2_19.

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Pitopang, Ramadhanil, Paul J. A. Keßler, S. Robbert Gradstein, Edi Guhardja, Sri S. Tjitrosudirdjo, and Harry Wiriadinata. "Tree Composition in Secondary Forest of Lore Lindu National Park, Central Sulawesi, Indonesia." In Land Use, Nature Conservation and the Stability of Rainforest Margins in Southeast Asia, 269–79. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-662-08237-9_15.

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Pombo, Anna R., Matthias Waltert, S. Supraptini Mansjoer, Ani Mardiastuti, and Michael Mühlenberg. "Home Range, Diet and Behaviour of the Tonkean Macaque (Macaca tonkeana) in Lore Lindu National Park, Sulawesi." In Land Use, Nature Conservation and the Stability of Rainforest Margins in Southeast Asia, 313–25. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-662-08237-9_18.

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Conference papers on the topic "Stability lobe"

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Kakoty, S. K., M. Kalita, and T. Thivagar. "Nonlinear Time Transient Stability Analysis of Multilobe Bearings." In World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-63325.

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In some specialized applications, plain circular bearing is mostly replaced by some other bearings, as plain bearing does not suit the stability requirements of high-speed machines and precision machine tools. Grooved circular bearings and multi-lobe bearings with two lobes, three lobes and four lobes are commonly used. The present work gives insight into nonlinear transient analysis of multi lobe journal bearing systems. An attempt has been made to evaluate the critical mass parameter (a measure of stability) for various values of aspect ratios besides finding out the steady state characteristics of multilobe journal bearings (two grooved, two lobe, three lobe and four lobe) such as load bearing capacity, Sommerfeld number and attitude angle At moderate and heavy load conditions (Sommerfeld number from 0.1 to 0.3), four-lobe bearing is most stable. Three-lobe bearing is the best in the range of Sommerfeld number from 0.3 to 0.8. Two-lobe bearing is found to be more stable than other bearings beyond this range.
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Corpus, William T., and William J. Endres. "An Analytical Model to Predict Chatter in Multi-Dimensional Periodically Time-Varying Machining Processes." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-42488.

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An approach is presented to determine the stability limits for machining processes that exhibit periodic time variation and multi-dimensional structural dynamics. The approach leverages the solution for the single-dimensional case, which identified an added set of stability lobes in addition to those corresponding to the time-invariant case. The solution is developed for two-dimensional dynamics for both a damped system and an undamped system; it may be expanded to any order and extended to three-dimensional dynamics. The undamped solution provides a mathematical description of the stability lobe locations along the speed axis and asymptotes for the damped case. Numerical time-domain simulation is used to confirm the analytical solution. While the agreement is good even for a first-order analytical result, yet another extra stability lobe, not seen in the one-dimensional case, is now seen in the numerical simulation results. Some of its characteristics are noted; however, further study is needed to understand its source.
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Lalley, Aaron, and Mark Bedillion. "Novel Direct Model for Machining Regenerative Chatter." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-65265.

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Regenerative machining chatter or resonance in the machining process has traditionally been modeled with the stability lobe approach. This paper presents a new time based direct simulation model and compares it with traditional stability lobe modeling. The direct model has the ability to discriminate directional and time information, resulting in a number of advantages over frequency-based stability lobe analysis.
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Szalai, Ro´bert, and Ga´bor Ste´pa´n. "Stability Boundaries of High-Speed Milling Corresponding to Period Doubling Are Essentially Closed Curves." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-42122.

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In this paper a new method for the stability analysis of high-speed milling processes is introduced. The approach is based on the construction of a characteristic function whose complex roots determine the stability of the system. By using the argument principle, the number of roots causing instability can be counted, and thus, an exact stability chart can be drawn. In the special case of period doubling bifurcation, the corresponding multiplier −1 is substituted into the characteristic function leading to an implicit formula of the stability boundaries. Further investigations show that all the period doubling boundaries are closed curves, except the first lobe at the highest cutting speeds. Together with the stability boundaries of Neimark-Sacker (or secondary Hopf) bifurcations, the unstable parameter domains are formed from the union of lobes and lenses.
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Strzelecki, S., and Z. Towarek. "Effect of Journal Misalignment on the Oil Film Pressure and Temperature Distribution of 3-Lobe Offset Journal Bearing." In World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-63828.

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The design of turbines and compressors operating at the high rotational speeds applies the 3-lobe journal bearings. In many cases the classic 3-lobe journal bearings supporting the rotors, are showing the problem of rotor stability. This problem can be avoided by the application of 3-lobe Offset bearings. This type of bearing fulfils the conditions of reliable bearing design and good stability in the case of high speed rotating machines.
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Friedrich, Jens, Henning Hartmann, Alexander Verl, and Armin Lechler. "Continuous learning support vector machine to estimate stability lobe diagrams in milling." In International FAIM Conference. DEStech Publications, Inc., 2014. http://dx.doi.org/10.14809/faim.2014.0641.

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Xu, Chao, Pingfa Feng, Dingwen Yu, Zhijun Wu, and Jianfu Zhang. "Stability Prediction of Milling Process With Closed Machining System Dynamics With Flexible Thin-Walled Workpiece." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-51454.

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Despite recent advances and improvements in modeling and prediction of the dynamics of the machining process, an efficient machining process is limited due to chatter and instability of machining system. In fact, the machining system contains various kinds of joints, which cause difficulties in dynamics modeling, simulation and prediction. Moreover, the flexible support system results in large deformation and violent vibration of the workpiece when machining, and the thin-walled workpiece easily gives rise to the chatter of the machining system. Therefore, the dynamics of the flexible support system was considered to calculate stability lobe diagram in the modeling of milling process. The whole machining system was regarded as a closed loop composed by the machine tool structures, support, workpiece and machining process. In this paper, the receptance coupling (RC) method was introduced to predict the dynamics of the closed machining system. A milling process was taken for example to predict the chatter limitations using the dynamics of closed model. The mathematical model of the machining system (machine tool structures, spindle, holder and tool), together with the details of joint contacts, was given based on the RC method. The RC model was used to obtain the dynamics of the system, while receptance of the tool point was coupled. Based on the coupling model of the machining system, the depth limitations under different speeds were estimated for the technology parameter optimization in milling process. The response was considered to be the sum of the cutting point and the support system. The flexibility of the support system was considered to be the feedback of the cutting stiffness. By this means, the traditional model was modified to calculate the stability lobe diagram based on the dynamics of the spindle and support system. Furthermore, the milling experiment was carried out to verify the prediction results, and the dominant natural frequencies of receptance at tool point were obtained by modal testing to define the stability lobe diagram. It was found that the chatter results matched well with the stability lobes. It was concluded that the support system with poor stiffness might cause violent chatter especially when the workpiece was thin-walled. The cutting depth limitations of the flexible support system were lower than that of the rigid one. Moreover, this closed model of the machining system is appropriate for the chatter prediction of the flexible support system or thin-walled workpiece, so it is helpful for a better parameter optimization.
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Phalle, Vikas M., and Satish C. Sharma. "Performance Analysis of Worn Misaligned 4-Lobe Multirecess Hybrid Journal Bearing System Compensated With Orifice Restrictor." In ASME/STLE 2012 International Joint Tribology Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/ijtc2012-61018.

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Owing to the fast technological developments, the operating conditions of the machines are becoming very stringent, exact and more demanding. Various journal bearing designs have been developed to prevent the undesired effect of bearing whirl. An example of a successful design is the four-lobe multirecess journal bearing. The bearing which having four curved segments that referred to as four lobes is the four-lobe multirecess journal bearing. Further, as the 4-lobe journal bearing is expected to run over a number of cycles during its lifetime, it is subjected to several start/stop operations. These transient periods causes the bearing bush to wear out between the recesses and significantly affects the bearing performance. The modified Reynolds equation governing the flow of lubricant in the clearance space of bearing have been solved including the combined effects of three aspects, the worn effect, the misalignment angle and offset factors, using an iterative scheme based on FEM and Newton-Raphson method. The simulated results have been presented for a wide range of offset factor δ, wear depth parameter, journal misalignment factors (φ, Ψ) and external load. The simulated results suggests that it is an imperative to account for the effect of wear along with misalignment of journal in order to predict the performance of the bearing accurately. Further, it has been observed that in general as the value of offset factor increases the static and dynamic performance of the 4-lobe four pocket worn misaligned hybrid journal bearing compensated with orifice restrictor is clearly affected as compared to similar four pocket unworn aligned hybrid circular journal bearing. Further the bearing having offset factor δ = 1.2 improves the stability due to increase in the bearing stiffness and reduced magnitude of the cross-stiffness components.
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Li, Weitao, Liping Wang, and Guang Yu. "Time Domain Study on the Construction Mechanism of Milling Stability Lobe Diagrams With Multiple Modes." In ASME 2021 16th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/msec2021-60227.

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Abstract The stability lobe diagram (SLD) is an important expression way of milling stability prediction result. The SLD obtained by only selecting the most flexible mode fails to predict the chatter if the milling process is dominated by multiple modes. To reveal the relationship between the SLD with multiple modes and the SLDs corresponding to each single mode, this paper studies the construction mechanism of the SLD with multiple modes by using the time domain method. First, the milling dynamic model of the tool with multiple modes is established. Then, the numerical method based on the Newton-Cotes rules is used to solve the milling dynamic model with multiple modes whose solution is in the form of the SLD. It shows that the SLD with multiple modes can be approximated by using the lowest envelope of the SLDs corresponding to each single mode. Finally, two study cases are adopted to verify the construction mechanism of the SLD with multiple modes. To verify the correctness of the SLD with multiple modes, a series of milling tests are carried out. The experimental results agree with the simulation results, which means the proposed time domain method can reveal the construction mechanism of the SLD with multiple modes.
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Conlon, Martin J., Azzedine Dadouche, and Waldemar M. Dmochowski. "Comparison of the Steady-State and Dynamic Performance of Two Fixed-Geometry Journal Bearings." In ASME 2011 Turbo Expo: Turbine Technical Conference and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/gt2011-46761.

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This paper evaluates two different journal bearings: a cylindrical bore plain journal bearing and a tri-lobe taper land bearing. Each bearing has the same nominal diameter (89mm) and aspect ratio (L/D = 0.7). The shaft rotational speed ranged from 6krpm to 14krpm and the bearing specific load from 700kPa to 2800kPa. The bearings’ steady-state performance is evaluated according to relative bearing and shaft displacement, bearing operating temperature and power loss. A frequency-domain analysis is used to determine bearing rotordynamic coefficients — it treats the bearing as a mass-spring-damper system. Excitation frequencies range between 20Hz and 350Hz. Ultimately, the tri-lobe taper land bearing offers better stability whereas the cylindrical bore plain journal bearing has a lower eccentricity and runs cooler for a given operating condition. The dynamic properties of the two bearings are found to be similar, although the higher stability of the tri-lobe taper land bearing is also reflected in the dynamic coefficients.
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Reports on the topic "Stability lobe"

1

Daanen, R. P., M. M. Darrow, and T. D. Hubbard. Frozen debris lobe stability, a function of thermal and hydrological processes (poster): American Geophysical Union, Fall Meeting, San Francisco, California, December 13, 2013. Alaska Division of Geological & Geophysical Surveys, December 2013. http://dx.doi.org/10.14509/26886.

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2

Šipka, Pero. Serbian WoS-indexed journals: What’s their use for the local scholarly community? Centre for Evaluation in Education and Science (CEON/CEES), October 2020. http://dx.doi.org/10.5937/cees-2017-03-1.

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It is in the national interest of small countries such as Serbia to have as many journals in WoS as possible. WoS indexing boosts visibility and internationality and rises journals impact and quality. However, once they reach WoS and stabilize their position, some local journals turn to profit-making strategies, introducing or significantly increasing authors' fees (APCs), which usually results in a larger influx of foreign authors who can afford to pay such fees. Consequently, domestic authors practically lose the space to publish in their traditional platforms. Here, we discuss the question if such journals should continue to enjoy the support from the national public R&D budget entitled to supporting local science.
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3

Daanen, R. P., M. M. Darrow, and T. D. Hubbard. Influence of catchment properties on stability of frozen debris lobes (presentation): Cordilleran Section of the Geological Society of America 111th Annual Meeting, Anchorage, Alaska, May 11-13, 2015. Alaska Division of Geological & Geophysical Surveys, 2017. http://dx.doi.org/10.14509/29815.

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