Journal articles: 'Stability lobe'

1

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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10

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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Ibañez, Aratz Iturgaiz, Pedro Jose Arrazola, and Klaus Bonde Ørskov. "Workpiece Material Influence on Stability Lobe Diagram." Procedia Manufacturing 47 (2020): 479–86. http://dx.doi.org/10.1016/j.promfg.2020.04.342.

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12

Chen, Ming, Weiwei Ming, and Xiaohui Zhang. "GRADE OF STABILITY IN FUZZY CHATTER STABILITY LOBE MODEL IN MILLING." Machining Science and Technology 15, no. 3 (July 2011): 306–23. http://dx.doi.org/10.1080/10910344.2011.600191.

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13

Dhupia, Jaspreet S., Bartosz Powalka, A. Galip Ulsoy, and Reuven Katz. "Effect of a Nonlinear Joint on the Dynamic Performance of a Machine Tool." Journal of Manufacturing Science and Engineering 129, no. 5 (April 17, 2007): 943–50. http://dx.doi.org/10.1115/1.2752830.

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This paper presents the effect of experimentally evaluated nonlinearities in a machine joint on the overall machine tool dynamic performance using frequency response functions and stability lobe diagrams. Typical machine joints are very stiff and have weak nonlinearities. The experimental evaluation of the nonlinear joint parameters of a commercial translational guide has been discussed in Dhupia et al., 2007, J. Vibr. Control, accepted. Those results are used in the current paper to represent the connection between the column and the spindle of an idealized column-spindle machine structure. The goal is to isolate and understand the effects of such joints on the machine tool dynamic performance. The nonlinear receptance coupling approach is used to evaluate the frequency response function, which is then used to evaluate the stability lobe diagrams for an idealized machine structure. Despite the weak nonlinearities in the joint, significant shifts in the natural frequency and amplitudes at resonance can be observed at different forcing amplitudes. These changes in the structural dynamics, in turn, can lead to significant changes in the location of chatter stability lobes with respect to spindle speed. These variations in frequency response function and stability lobe diagram of machine tools due to nonlinearities in the structure are qualitatively verified by conducting impact hammer tests at different force amplitudes on a machine tool.

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14

Friedrich, Jens, Jonas Torzewski, and Alexander Verl. "Online Learning of Stability Lobe Diagrams in Milling." Procedia CIRP 67 (2018): 278–83. http://dx.doi.org/10.1016/j.procir.2017.12.213.

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15

Hsiao, Te Ching, and Shyh Chour Huang. "The Effect of Cutting Process Parameters on the Stability in Milling." Advanced Materials Research 887-888 (February 2014): 1200–1204. http://dx.doi.org/10.4028/www.scientific.net/amr.887-888.1200.

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In the milling process, the dynamic system in the cutting process is composed of the tool, workpiece, and machine tools themselves. Therefore the mill geometric parameter, workpiece material behavior, and the modal parameters of the cutting system all will influence the stability in milling. Using FLN method and convolution force model to predict the chatter stability of milling process, and discussing the effect of milling parameter on the stability in this article. According to the result: with the increase of the tool diameter, stiffness, damping ratio or the reducing of tangential cutting force coefficient and radial width of cut, the stability lobe diagram tends to move upward. With the increase of natural frequency, the stability lobe diagram tends to move to right side. With the increase of the number of tooth, the stability lobe diagram tends to move downward.

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16

Zheng, Charles M., Chou-Fu Liang, Hai-Yi Cai, and Shui-Shen Zhang. "Identification of process damping for chatter prediction in milling." MATEC Web of Conferences 175 (2018): 02002. http://dx.doi.org/10.1051/matecconf/201817502002.

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Traditionally, forecasting stability lobe diagram in milling is limited by complex damping identification procedures, so only structural damping from the impact experiment is used for predicting stability lobe diagram in most milling cases. In this study, by using the mathematical expressions among damping ratio, “critical limiting depth of cut” and “worst spindle speed”, it is shown that the predicted “critical limiting depth of cut” based on the structural damping divided by the measured “critical limiting depth of cut” can be approximately equal to the structural damping divided by the total damping. Based on this relationship, it is easy to estimate the total damping or process damping from the experiment within the selected spindle speeds. In practice, this paper presents an easy method for predicting stability lobe diagram using the total damping. At the same time, experiments have confirmed that using the prediction model of total damping can more accurately predict the stability lobe diagram.

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17

Zhao, D., and Q. Zhang. "Regenerative Chatter Stability and Hopf Bifurcation Analysis in Milling System." Advanced Materials Research 739 (August 2013): 400–407. http://dx.doi.org/10.4028/www.scientific.net/amr.739.400.

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The shifted Chebyshev polynomials and Floquet theory are both adopted for the prediction regenerative chatter stability and Hopf bifurcation in milling. The influences of the system parameter on the stability of the milling system have been analyzed. The stability lobe diagrams are obtained. The result shows that the shifted Chebyshev polynomials method is more accurate than the semi-discretion scheme for spindle speed lower than 3500 round per minutes. The stability in milling can well be predicted by the cutting depth and feed rate lobes diagrams. Only Hopf bifurcations are detected by the Eigen-value analysis. The stable solution transform from the stable equilibrium point to the quasi-periodic oscillation after Hopf bifurcation.

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18

Ahmed, Ahmed H., Christopher P. Ptak, Michael K. Fenwick, Ching-Lin Hsieh, Gregory A. Weiland, and Robert E. Oswald. "Dynamics of Cleft Closure of the GluA2 Ligand-binding Domain in the Presence of Full and Partial Agonists Revealed by Hydrogen-Deuterium Exchange." Journal of Biological Chemistry 288, no. 38 (August 12, 2013): 27658–66. http://dx.doi.org/10.1074/jbc.m113.495564.

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The majority of excitatory neurotransmission in the CNS is mediated by tetrameric AMPA receptors. Channel activation begins with a series of interactions with an agonist that binds to the cleft between the two lobes of the ligand-binding domain of each subunit. Binding leads to a series of conformational transitions, including the closure of the two lobes of the binding domain around the ligand, culminating in ion channel opening. Although a great deal has been learned from crystal structures, determining the molecular details of channel activation, deactivation, and desensitization requires measures of dynamics and stabilities of hydrogen bonds that stabilize cleft closure. The use of hydrogen-deuterium exchange at low pH provides a measure of the variation of stability of specific hydrogen bonds among agonists of different efficacy. Here, we used NMR measurements of hydrogen-deuterium exchange to determine the stability of hydrogen bonds in the GluA2 (AMPA receptor) ligand-binding domain in the presence of several full and partial agonists. The results suggest that the stabilization of hydrogen bonds between the two lobes of the binding domain is weaker for partial than for full agonists, and efficacy is correlated with the stability of these hydrogen bonds. The closure of the lobes around the agonists leads to a destabilization of the hydrogen bonding in another portion of the lobe interface, and removing an electrostatic interaction in Lobe 2 can relieve the strain. These results provide new details of transitions in the binding domain that are associated with channel activation and desensitization.

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Wan, Min, Yi Ting Wang, Wei Hong Zhang, and Jian Wei Dang. "Effect of Cutting Conditions on the Stability Lobes for End Milling Process." Advanced Materials Research 139-141 (October 2010): 748–51. http://dx.doi.org/10.4028/www.scientific.net/amr.139-141.748.

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Milling process will be dominated by multiple delays due to the effect of the cutter runout or the pitch angles of the cutter. In this paper, research efforts are focused on the dynamic behavior of milling processes under different cutting condition parameters such as different radial immersions, feed directions, feeds per tooth and helix angles. To improve the prediction accuracy of stability lobe, the combined influences of feed rate and cutter runout on the stability lobes are also taken into account. The basic principle of the method presented in one existing work is applied to examine the asymptotic stability trends for both down milling and up milling. Some new phenomena for certain combinations of cutting parameters are shown and explained in detail. It is found that as cutter runout occurs, feed per tooth, feed direction and cutter helix angle have great effects on the stability lobes.

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Jensen, S. A., and Y. C. Shin. "Stability Analysis in Face Milling Operations, Part 1: Theory of Stability Lobe Prediction." Journal of Manufacturing Science and Engineering 121, no. 4 (November 1, 1999): 600–605. http://dx.doi.org/10.1115/1.2833075.

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This paper involves development of an algorithm to predict stability lobes in face milling operation. The modeling is based on frequency domain analysis and is an extension of Budak and Altintas to a three dimensional case. It considers the effects of insert and cutter geometry, cutting conditions, process nonlinearity, entry and exit angles and the fully dimensional structural dynamics of both the machine tool and workpiece, including axial dynamics which are often neglected by many researchers. In addition, the predictive capability of stability lobes by the presented models is compared with those results obtained by time domain simulations.

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Szalai, Róbert, and Gábor Stépán. "Lobes and Lenses in the Stability Chart of Interrupted Turning." Journal of Computational and Nonlinear Dynamics 1, no. 3 (November 15, 2003): 205–11. http://dx.doi.org/10.1115/1.2198216.

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In this paper, a new method for the stability analysis of interrupted turning 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 for 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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Guo, Yan Yan, Wan Tao He, and Can Zhao. "Stability Research on High Speed Milling of Aviation Aluminum Alloy." Advanced Materials Research 188 (March 2011): 263–67. http://dx.doi.org/10.4028/www.scientific.net/amr.188.263.

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The stability of cutting system is an important research in high-speed machining area. It is widely used in engineering practice. First, this paper studies the milling forces and their change law when milling aluminum alloy through orthogonal experiment. And it solves the milling coefficients. Second, it modal parameters of milling system such as natural frequency, modal mass and equivalent stiffness by hammer experiment. On this basis, it draws the stability lobe about the spindle speed and radial depth of cut and verifies the accuracy of the stability lobe.

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Qiu, Jian, and Renpeng Ge. "An improved stability lobe and turning chatter characteristic investigation." International Journal of Mechanical Sciences 149 (December 2018): 338–48. http://dx.doi.org/10.1016/j.ijmecsci.2018.10.006.

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Mehta, N. P., and S. S. Rattan. "Stability analysis of three-lobe bearings with pressure dams." Wear 167, no. 2 (August 1993): 181–85. http://dx.doi.org/10.1016/0043-1648(93)90323-e.

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25

SUN, Hongzhe, Hongyan LI, Anne B. MASON, Robert C. WOODWORTH, and Peter J. SADLER. "N-lobe versus C-lobe complexation of bismuth by human transferrin." Biochemical Journal 337, no. 1 (December 17, 1998): 105–11. http://dx.doi.org/10.1042/bj3370105.

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Interactions of recombinant N-lobe of human serum transferrin (hTF/2N) with Bi3+, a metal ion widely used in medicine, have been investigated by both UV and NMR spectroscopy. The bicarbonate-independent stability constant for Bi3+ binding (K*) to hTF/2N was determined to be log K* 18.9±0.2 in 5 mM bicarbonate/10 mM Hepes buffer at 310 K, pH 7.4. The presence of Fe3+ in the C-lobe of intact hTF perturbed Bi3+ binding to the N-lobe, whereas binding of Bi3+ to the C-lobe was unaffected by the presence of Fe3+ in the N-lobe. Reactions of Bi3+ (as bismuth nitrilotriacetate or ranitidine bismuth citrate) with hTF/2N in solutions containing 10 mM bicarbonate induced specific changes to high-field 1H-NMR peaks. The 1H co-ordination shifts induced by Bi3+ were similar to those induced by Fe3+ and Ga3+, suggesting that Bi3+ binding causes similar structural changes to those induced by hTF/2N. 13C-NMR data showed that carbonate binds to hTF/2N concomitantly with Bi3+.

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Prashad, Har. "Evaluation of Dynamic Coefficients of a Two-Lobe Journal Bearing Using an Electrical Analogy Approach." Journal of Tribology 118, no. 3 (July 1, 1996): 657–62. http://dx.doi.org/10.1115/1.2831588.

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A theoretical approach to evaluating capacitance, resistance, capacitive reactance, and impedance of the lower and upper lobes of a two-lobe elliptical hydrodynamic journal bearing under various operating conditions is developed. It is established that the change in capacitance and resistance with the change in eccentricity ratios is nonlinear. The capacitance and resistance, thus determined, are correlated with the dynamic coefficients of bearings using an electrical analogy. It is found that the stiffness and damping coefficients are higher for two-lobe bearings as compared to those of cylindrical bearings having identical dimensional parameters and operating under similar conditions. The analysis may have the potential to diagnose the stability regime of a bearing through the bearing’s electrical parameters. The electrical analogy may be a useful alternative to conventional techniques.

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Tsai, Ming Chang, Te Ching Hsiao, and Shyh Chour Huang. "Analysis of the Effect the Modal-Parameter on the Milling Stability." Applied Mechanics and Materials 372 (August 2013): 459–62. http://dx.doi.org/10.4028/www.scientific.net/amm.372.459.

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In the past few years, it has become a tendency to develop machinery of high speeds and high precision. In order to meet the need for high-speed manufacturing of high precision components, the machine tools structure must be very stiff and have high cutting stability levels. Should the process of the firsthand milling be unstable, the effects include cutting tool breakages, decrease in surface accuracy and could even shorten the machine tolls lifespan. Thus, in the manufacturing of milling, chattering often causes problems for the manufacturer. To prevent cases of milling chattering, there is a need to use a chatter stability lobe to predict the chatter stability and to analyze the effect the modal-parameter has on the stability of milling. This research paper uses the Zero-Order Analytical Method (ZOA) to analyze and compare the effects modal-parameter (natural frequency, damping ratio, modal stiffness) has on the stability of the milling system. The results show that level of stiffness and the damping ratio influences the vertical shape of the chatter stability lobes while the natural frequency affects the lateral shape of the lobes.

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Sharma, Satish C., and Prashant B. Kushare. "Nonlinear transient response of rough symmetric two lobe hole entry hybrid journal bearing system." Journal of Vibration and Control 23, no. 2 (August 9, 2016): 190–219. http://dx.doi.org/10.1177/1077546315575831.

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The present paper describes the effect of surface roughness orientation pattern on the nonlinear transient response of symmetric two lobe capillary compensated hole entry hybrid journal bearing. Nonlinear equations of motion have been solved with the Runge-Kutta method. The stability of the journal bearing system has been studied by obtaining the journal center motion trajectories. The results of the study reveal that the surface roughness pattern significantly changes the stability of capillary compensated two lobe hole entry hybrid journal bearing. Hence, from the bearing stability point of view, a proper selection of the surface roughness pattern and bearing geometry is essential.

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Zhang, Nan, Yaoyao Shi, Zhen Chen, Hongxia Chen, Jia Liu, and Pan Zhao. "Chatter reliability prediction of side milling blisk." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 39, no. 1 (February 2021): 111–18. http://dx.doi.org/10.1051/jnwpu/20213910111.

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During the blisk side milling, the blade is thin and the tool suspension length is large, which is easy to occur milling system chatter. The wavy surface left by chatter has great effect on the surface roughness and service performance of the aero-engine blisk. To accurately predict the stability of the blisk side milling, the influence of random variables on the machining stability was considered. In this paper, the chatter reliability model of the blisk side milling system was established using the first-order second-moment method. The model takes structural parameters and spindle speed as random variables and chatter frequency as intermediate variables. The chatter reliability model was used to draw the reliability lobe diagram, which can be used to divide the machining reliability area. The effectiveness of this method was verified by experiments and compared with Monte Carlo method. The validation results showed that the reliability lobe diagram can be used to determine the stability probability prediction of blisk side milling and can replace the traditional stability lobe diagram.

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N.S, Belwalkar, Mohite S.S, and Kashyapi G.V. "IDENTIFICATION OF STABILITY LOBE DIAGRAM FOR MILLING USING VIBRATION ANALYSIS." International Journal on Design and Manufacturing Technologies 9, no. 2 (2015): 23–27. http://dx.doi.org/10.18000/ijodam.70155.

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Lee, Hyuk, Dohun Chin, and Moonchul Yoon. "Characteristics of Chatter Stability Lobe in 2-DOF Machining System." Korean Society of Manufacturing Process Engineers 18, no. 7 (July 31, 2019): 1–7. http://dx.doi.org/10.14775/ksmpe.2019.18.7.001.

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Palmigiano, Agostina, Jesús Pastor, Rafael García de Sola, and Guillermo J. Ortega. "Stability of Synchronization Clusters and Seizurability in Temporal Lobe Epilepsy." PLoS ONE 7, no. 7 (July 23, 2012): e41799. http://dx.doi.org/10.1371/journal.pone.0041799.

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Mehta, N. P., S. S. Rattan, Gian Bhushan, and N. K. Batra. "Stability analysis of an inverted three-lobe pressure dam bearing." Journal of Mechanical Science and Technology 26, no. 8 (August 2012): 2425–30. http://dx.doi.org/10.1007/s12206-012-0632-z.

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Et. al., Jeevan Raju B,. "Design and optimized analysis of high speed precise machine tool spindles." Turkish Journal of Computer and Mathematics Education (TURCOMAT) 12, no. 2 (April 11, 2021): 2965–77. http://dx.doi.org/10.17762/turcomat.v12i2.2336.

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Upcoming machine tools need to be extremely efficient systems to maintain the needed intellectual performance and stability. The spindle tool system is necessary to optimize which enhances the rigidity of the spindle and in turn produces the cutting stability with higher productivity. Prediction of the dynamic behavior at spindle tool tip is therefore an important criterion for assessing the machining stability of a machine tool at design stage. In this work, a realistic dynamic high-speed spindle /milling tool holder/ tool system model is elaborated on the basis of rotor dynamics predictions. The integrated spindle tool system in analyzed with the Timoshenko beam theory by including the effects of shear and rotary deformation effects. Using the frequency response at the tool tip the corresponding stability lobe diagrams are plotted for the vertical end mill system. Furthermore an optimization study is carried out at design stage for the bearing system and the rotor positions for maximizing the chatter vibration free cutting operation at the desired depth of cuts with precise rotational speeds.It is markedly found that the first mode of vibration had a large impact on the dynamic stability of the system. The parametric studies are conducted such as tool overhang and bearing span and the influence of these on the system dynamics are identified and the corresponding stability lobe diagrams are plotted. It is evidently found that the second mode of the frequency response has critically affected the bearing span and competing lobes are identified. These results are assisted to design a spindle bearing system at the desired machining conditions. A neural network based observer is designed based on the simulation resultsto predict optimum design parameter values.

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Tang, A. J., and Zhan Qiang Liu. "Effect of Helix Angle and Normal Rake Angle on Stability in End Milling." Advanced Materials Research 69-70 (May 2009): 394–98. http://dx.doi.org/10.4028/www.scientific.net/amr.69-70.394.

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Chatter phenomenon often occurs during end milling of metal-cutting and becomes a common limitation to achieve high productivity and part quality. This paper studies the relationship expression between the parameters of oblique cutting and milling coefficients by analyzing the geometrical relationship of oblique cutting, and derives the mathematic expressions in theory between the cutter parameters and chatter. For the purpose of chatter avoidance, this paper studies the effect of helix angle and normal rake angle on milling stability under the condition of the same milling parameters, and plots the three-dimensional stability lobes of the spindle speed, axial and radial depths. It can be found that the milling stability is increased with the increment of helix angle and normal rake angle. Through the three-dimensional lobe, it is possible to choose the appropriate cutter parameters to reduce and avoid the chatter.

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36

Corpus, William T., and William J. Endres. "Added Stability Lobes in Machining Processes That Exhibit Periodic Time Variation, Part 2: Experimental Validation." Journal of Manufacturing Science and Engineering 126, no. 3 (August 1, 2004): 475–80. http://dx.doi.org/10.1115/1.1765136.

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Physical experimentation using a kinematically simple straight-edged orthogonal tube-end turning process both verifies the existence of added stability lobes as well as shows good agreement with the analytical solution and numerical simulations of Part 1. The experimental results also verify the added-lobe chatter frequency to be one-half the tooth frequency. Given validation of the analysis and simulation, they are then used to show the effects of variables not easily explored through experimental means, such as overlap factor, multi-tooth cutting, general periodicity and damping. The added-lobes are shown to exist with a zero overlap factor (i.e., no regeneration) and to scale in magnitude (limiting width of cut) relative to overlap factor. Furthermore, the added lobes are shown to exist for multi-tooth machining even when there are no periods of full cutter disengagement (i.e., no free vibration) as well as nonintermittent machining where periodic time variation exists for other reasons, such as spatially dependent stiffness. Finally, it is shown that damping primarily affects the bottom of the added lobes with minimal effect on the higher regions of the boundaries, indicating that structural damping becomes less important at ultrahigh speeds in cases for which the added lobes are the limitation.

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Rashidi Meybodi, R., M. Zare Mehrjardi, and A. D. Rahmatabadi. "Tilt angle effects on the performance of micropolar lubricated noncircular journal bearings." Industrial Lubrication and Tribology 69, no. 4 (July 10, 2017): 536–49. http://dx.doi.org/10.1108/ilt-03-2016-0041.

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Purpose The purpose of this paper is to study tilt angle effects as design parameters of noncircular bearings, on the linear dynamic analyses of micropolar lubricated circular, two, three and four lobe journal bearings. Design/methodology/approach Reynolds equation in dynamic state is modified considering the micropolarity characteristics of lubricant, and it is solved using generalized differential quadrature method. The perturbed components of the dynamic pressure are extracted based on the linear dynamic model. To explain the transient state of the governing equation, through the linear dynamic approach, the whirling motion of rotor around the steady state position is assumed to be harmonic. Findings It is observed from the results that tilt angle has significant effects on the steady state and stability performance of lobed journal bearings. It may be selected suitably to improve the performance of rotor-bearing system, while all other lubricant properties and noncircular bearing design parameters are kept fixed. Results show that among the three types of bearings considered, the dynamic performance of two lobe bearings are more affected by the variation of tilt angle. Originality/value The present study is mainly concerned with the effects of tilt angle as a design parameter on the stability performance of a hydrodynamic noncircular journal bearing lubricated with micropolar fluid.

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38

Friedrich, Jens, Christoph Hinze, Anton Renner, Alexander Verl, and Armin Lechler. "Estimation of stability lobe diagrams in milling with continuous learning algorithms." Robotics and Computer-Integrated Manufacturing 43 (February 2017): 124–34. http://dx.doi.org/10.1016/j.rcim.2015.10.003.

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Li, Kai, Songping He, Hongqi Liu, Xinyong Mao, Bin Li, and Bo Luo. "Bayesian uncertainty quantification and propagation for prediction of milling stability lobe." Mechanical Systems and Signal Processing 138 (April 2020): 106532. http://dx.doi.org/10.1016/j.ymssp.2019.106532.

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Löser, Michael, and Knut Großmann. "Influence of Parameter Uncertainties on the Computation of Stability Lobe Diagrams." Procedia CIRP 46 (2016): 460–63. http://dx.doi.org/10.1016/j.procir.2016.04.031.

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41

Tyler, Christopher T., John Troutman, and Tony L. Schmitz. "Radial depth of cut stability lobe diagrams with process damping effects." Precision Engineering 40 (April 2015): 318–24. http://dx.doi.org/10.1016/j.precisioneng.2014.11.004.

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42

Aly, M., and N. B. Turk-Browne. "Top-down attention modulates representational stability in the medial temporal lobe." Journal of Vision 14, no. 10 (August 22, 2014): 631. http://dx.doi.org/10.1167/14.10.631.

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43

Denkena, Berend, Benjamin Bergmann, and Svenja Reimer. "Analysis of different machine learning algorithms to learn stability lobe diagrams." Procedia CIRP 88 (2020): 282–87. http://dx.doi.org/10.1016/j.procir.2020.05.049.

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Quintana, Guillem, Joaquim Ciurana, Inés Ferrer, and Ciro A. Rodríguez. "Sound mapping for identification of stability lobe diagrams in milling processes." International Journal of Machine Tools and Manufacture 49, no. 3-4 (March 2009): 203–11. http://dx.doi.org/10.1016/j.ijmachtools.2008.11.008.

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Pai, R., and B. C. Majumdar. "Stability of submerged four-lobe oil journal bearings under dynamic load." Wear 154, no. 1 (April 1992): 95–108. http://dx.doi.org/10.1016/0043-1648(92)90245-4.

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Bauer, Daniela, Dale R. Merz, Benjamin Pelz, Kelly E. Theisen, Gail Yacyshyn, Dejana Mokranjac, Ruxandra I. Dima, Matthias Rief, and Gabriel Žoldák. "Nucleotides regulate the mechanical hierarchy between subdomains of the nucleotide binding domain of the Hsp70 chaperone DnaK." Proceedings of the National Academy of Sciences 112, no. 33 (August 3, 2015): 10389–94. http://dx.doi.org/10.1073/pnas.1504625112.

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The regulation of protein function through ligand-induced conformational changes is crucial for many signal transduction processes. The binding of a ligand alters the delicate energy balance within the protein structure, eventually leading to such conformational changes. In this study, we elucidate the energetic and mechanical changes within the subdomains of the nucleotide binding domain (NBD) of the heat shock protein of 70 kDa (Hsp70) chaperone DnaK upon nucleotide binding. In an integrated approach using single molecule optical tweezer experiments, loop insertions, and steered coarse-grained molecular simulations, we find that the C-terminal helix of the NBD is the major determinant of mechanical stability, acting as a glue between the two lobes. After helix unraveling, the relative stability of the two separated lobes is regulated by ATP/ADP binding. We find that the nucleotide stays strongly bound to lobe II, thus reversing the mechanical hierarchy between the two lobes. Our results offer general insights into the nucleotide-induced signal transduction within members of the actin/sugar kinase superfamily.

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Yadav, Saurabh K., Arvind K. Rajput, Nathi Ram, and Satish C. Sharma. "Stability analysis of a rigid rotor supported by two-lobe hydrodynamic journal bearings operating with a non-Newtonian lubricant." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 233, no. 6 (October 15, 2018): 884–98. http://dx.doi.org/10.1177/1350650118806377.

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In the present work, an investigation has been performed on a rigid rotor supported by two-lobe journal bearings operating with a non-Newtonian lubricant. The governing Reynolds equation for pressure field is solved by using non-linear finite element method. Further to study the dynamic stability of the bearing system, governing equation of motion for the rotor position is solved by fourth order Runge–Kutta method. Bifurcation and Poincaré maps of two-lobe bearings are presented for different values of the non-Newtonian parameter and bearing ellipticity ratio. The numerical results illustrate that the ellipticity of a bearing with a dilatant lubricant improve the stability of the rotordynamic system.

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Gaber, Omar, and Seyed M. Hashemi. "Effects of Machine Tool Spindle Decay on the Stability Lobe Diagram: An Analytical-Experimental Study." Shock and Vibration 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/4390185.

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An analytical-experimental investigation of machine tool spindle decay and its effects of the system’s stability lobe diagram (SLD) is presented. A dynamic stiffness matrix (DSM) model for the vibration analysis of the OKADA VM500 machine spindle is developed and is validated against Finite Element Analysis (FEA). The model is then refined to incorporate flexibility of the system’s bearings, originally modeled as simply supported boundary conditions, where the bearings are modeled as linear spring elements. The system fundamental frequency obtained from the modal analysis carried on an experimental setup is then used to calibrate the DSM model by tuning the springs’ constants. The resulting natural frequency is also used to determine the 2D stability lobes diagram (SLD) for said spindle. Exploiting the presented approach and calibrated DSM model it is shown that a hypothetical 10% change in the natural frequency would result in a significant shift in the SLD of the spindle system, which should be taken into consideration to ensure chatter-free machining over the spindle’s life cycle.

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Zhao, Zhengcai, Junming Hou, and Yucan Fu. "Measurement-Based Modal Analysis and Stability Prediction on Turn-Milling of Hollow Turbine Blade." Shock and Vibration 2020 (September 24, 2020): 1–9. http://dx.doi.org/10.1155/2020/8861373.

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Hollow blades with honeycomb structures are increasingly used in the turbine engines for reducing weight and saving costs. The hollow blade is a typical thin-walled structural part with low stiffness, the machining system of which is often unstable and likely to chatter. The most effective solution to avoid the machining chatter is to guide the hollow blade to be machined in a stable machining zone. This paper proposes a measurement-based approach for modal analysis and stability prediction of turn-milling hollow blade. The impact test was carried out to achieve the FRF curves on the hollow blade and the milling tool. An extremum method was employed to obtain an equivalent FRF curve, from which the modal parameters involving the natural frequency, damping ratio, and stiffness were computed. Afterwards, the semidiscretization method was used to draw a stability lobe diagram to predict the stability when turn-milling hollow blades. The experimental results confirm the feasibility of the predicted stability lobe diagram.

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Wang, Xiu Zhen, Ri Feng Wang, Jian Hui Chen, Wei Quan Gu, Yue Gu, Hong Xia Wang, and Shu Lei Lang. "Stability of Number-Processing Based on Information Granularity Associative with Parietal Cortex." Applied Mechanics and Materials 519-520 (February 2014): 769–74. http://dx.doi.org/10.4028/www.scientific.net/amm.519-520.769.

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Stability, the ability to automatically extract and produce the efficient and accurate results of a defined problem without making epistemic assumptions, is discussed here as a possible memory system for understanding complex cognitive functions of the arithmetical learning. Stability is of top priority because it may typify organization of granule (knowledge-based information unit) structure. Memory efficiencies are that they depend on both linguistic factors and exposure to arithmetic training during granule formation or consolidation, supporting the idea of analog coding of numerical representations. Neuroimaging studies suggest that the parietal lobe as a potential substrate for a domain-specific representation of numeric quantities and associative memory mechanisms in stability, and results from these studies indicate that there may be the organization of number-related processes of stability in the parietal lobe. Stability seems to depend on the automatic information-processing system's response to experiential knowledge combining granularity (degree of detail or precision), maturational constraints, spatial factors (mental number line) and linguistic factors, making it an ideal candidate for understanding how these interactions play out in the cognitive arithmetic system.

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Journal articles on the topic 'Stability lobe'

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