Academic literature on the topic 'Spindle stiffness'
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Journal articles on the topic "Spindle stiffness"
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Yang, Zhaohui, Hui Chen, and Tianxiang Yu. "Effects of rolling bearing configuration on stiffness of machine tool spindle." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 232, no. 5 (February 22, 2017): 775–85. http://dx.doi.org/10.1177/0954406217693659.
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Rolling bearings are widely used in the complex mechanical systems as important components. With the advancement in the manufacturing technology, the requirements of high-performance machining tool became essential. A bearing is one of the most important components of spindle, and it is a crucial factor in determining the overall quality. The configuration of bearings of spindle is the key problem during high-performance spindle design, which influences the performance of spindle, especially stiffness. This paper aims to develop a method to analyze various spindle stiffnesses with different configurations of bearing to support the optimization of spindle. Firstly, a quasi-static model is established to solve stiffness matrix of bearing, and then a spindle-bearing system mathematical model is established. Secondly, the stiffness matrix of bearing is added into the whole system to form an integrated spindle-bearings model. Finally, the spindle stiffness with different bearing configurations are analyzed. The results indicate that the number of bearings influences the spindle radial stiffness and bearing direction affects the spindle axial stiffness. Once the number and direction are specified, reasonable pre-load method, shorter overhang, and proper span can greatly improve the spindle dynamic characteristics. In addition, an experimental spindle is designed and fabricated to test various axial stiffnesses with different bearing configurations, and stiffness characteristics of commonly used bearing configurations are summarized from the experimental results and provide useful guide for the spindle design.
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Loram, Ian D., Martin Lakie, Irene Di Giulio, and Constantinos N. Maganaris. "The Consequences of Short-Range Stiffness and Fluctuating Muscle Activity for Proprioception of Postural Joint Rotations: The Relevance to Human Standing." Journal of Neurophysiology 102, no. 1 (July 2009): 460–74. http://dx.doi.org/10.1152/jn.00007.2009.
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Proprioception comes from muscles and tendons. Tendon compliance, muscle stiffness, and fluctuating activity complicate transduction of joint rotation to a proprioceptive signal. These problems are acute in postural regulation because of tiny joint rotations and substantial short-range muscle stiffness. When studying locomotion or perturbed balance these problems are less applicable. We recently measured short-range stiffness in standing and considered the implications for load stability. Here, using an appropriately simplified model we analyze the conversion of joint rotation to spindle input and tendon tension while considering the effect of short-range stiffness, tendon compliance, fluctuating muscle activity, and fusimotor activity. Basic principles determine that when muscle stiffness and tendon compliance are high, fluctuating muscle activity is the greatest factor confounding registration of postural movements, such as ankle rotations during standing. Passive and isoactive muscle, uncomplicated by active length fluctuations, enable much better registration of joint rotation and require fewer spindles. Short-range muscle stiffness is a degrading factor for spindle input and enhancing factor for Golgi input. Constant fusimotor activity does not enhance spindle registration of postural joint rotations in actively modulated muscle: spindle input remains more strongly associated with muscle activity than joint rotation. A hypothesized rigid α–γ linkage could remove this association with activity but would require large numbers of spindles in active postural muscles. Using microneurography, the existence of a rigid α–γ linkage could be identified from the correlation between spindle output and muscle activity. Basic principles predict a proprioceptive “dead zone” in the active agonist muscle that is related to the short-range muscle stiffness.
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Chen, Shao Hsien, Shang Te Chen, and Chien Cheng Hsu. "The Impact of Different Axial Oil Chamber Design on Hydrostatic Spindle." Applied Mechanics and Materials 789-790 (September 2015): 296–99. http://dx.doi.org/10.4028/www.scientific.net/amm.789-790.296.
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High-precision machining and large-scale tool are the most primary development trend of current machine tool and hydrostatic products are key technologies of high-precision machining equipments. However, these equipments mostly process miniature components, thus the adopted tools are relatively small and the spindles mainly use are mainly built-in types of HSK32 to HSK25 with revolutions speed over 25,000rpm. Some processing equipments are even equipped with hydrostatic or gas-static spindles. The study extends the axial oil chamber to radial ones to expand the action area of axial oil pressure and form a closed oil seal edge by combining the radial clearance. Consequently, the axial bearing stiffness can be enhanced to enlarge the application scope of hydrostatic spindle. The design mode can enhance axial stiffness of spindle modules or strengthen the stiffness of hydrostatic spindle in a ball screw.
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Sakamoto, Haruhisa, Yuhei Maeki, and Shinji Shimizu. "Change in Dynamic Characteristics of Spindle for Machining Centers Caused by Chucking Mechanism of Clamped Toolholders." Key Engineering Materials 523-524 (November 2012): 521–26. http://dx.doi.org/10.4028/www.scientific.net/kem.523-524.521.
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In this study, the effects of clamping toolholders on the dynamic characteristics of spindle systems are evaluated experimentally. In the experiments, the transfer functions are obtained by the impulse response method, and then, the dynamic characteristic parameters are identified based on the vibration model of single-degree of freedom. Two types of machining center spindles and four types of toolholders are evaluated. From the experimental results, the following are revealed: (1) the clamping toolholder enhances the vibration amplitude markedly compared with that of the spindle not clamping toolholder. (2) The different chucking mechanisms clearly change the dynamic stiffness of the spindle systems. (3) The order of magnitude of the dynamic stiffness of the spindle systems agrees well with that of the isolated toolholders. It is confirmed experimentally that clamping of the appropriate toolholder improves the dynamics stiffness of the spindle systems for machining centers.
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Wang, Liping, Binbin Zhang, Jun Wu, Qinzhi Zhao, and Junjian Wang. "Stiffness modeling, identification, and measuring of a rotating spindle." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 234, no. 6 (December 1, 2019): 1239–52. http://dx.doi.org/10.1177/0954406219890368.
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The stiffness of a spindle at high speeds has a significant effect on the quality of the cutting surface and the machining accuracy. However, the spindle stiffness is difficult to be detected directly when the spindle is rotating, and the measured stiffness values are usually coupled with other parts of the spindle–tool system (such as toolholder, spindle–toolholder joint, tool). This paper presents a comprehensive method to deal with the stiffness modeling, identification, and measuring of a rotating spindle. Based on the deflection equation and the principle of superposition, the stiffness model is derived, for a spindle–tool system including a spindle, a specially manufactured toolholder, and a spindle–toolholder joint. A three-step identification algorithm is proposed to decouple and identify the actual spindle stiffness value. First, when the spindle is static, the stiffness values of the shaft, toolholder, and joint are obtained by using the least-squares method. Second, when the spindle is rotating, the stiffness values of the rear bearings and front bearings are identified based on the spindle error analysis method. Third, the stiffness values of the spindle under different rotating conditions are calculated based on the identification results from the previous two steps. Furthermore, the stiffness model and identification algorithm are verified experimentally on an instrumented spindle. The static stiffness value of the same spindle is also measured and compared with the stiffness value under rotating conditions subsequently. This work is useful and can be utilized as a guide for spindle stiffness testing and spindle performance evaluation to spindle manufacturers.
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Kondo, Ryo, Daisuke Kono, and Atsushi Matsubara. "Evaluation of Machine Tool Spindle Using Carbon Fiber Composite." International Journal of Automation Technology 14, no. 2 (March 5, 2020): 294–303. http://dx.doi.org/10.20965/ijat.2020.p0294.
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Spindle is one of the most important component of machine tools because spindle’s performance including thermal property and dynamic property greatly influences the accuracy and productivity in machining process. This study investigates the effect of the application of carbon fiber reinforced plastic (CFRP) to the spindle shaft on the performance of machine tool spindles. CFRP and steel spindle shafts with the same geometry were developed for fair comparison. Thermal and dynamic properties of the developed shaft and spindle unit were evaluated and compared. The experimental and simulation results showed that the CFRP spindle shaft improved the axial thermal displacement and dynamic stiffness. The axial thermal displacement was decreased to 1/3 of that of the steel spindle. The compliance was also decreased to 1/2. The design of the thermal displacement distribution around the bearing should be an important issue in the CFRP spindle for the thermal stability of the dynamic property.
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Chen, Runlin, Xingzhao Wang, Chen Du, Jun Zha, Kai Liu, and Xiaoyang Yuan. "Stiffness Model and Experimental Study of Hydrostatic Spindle System considering Rotor Swing." Shock and Vibration 2020 (May 15, 2020): 1–8. http://dx.doi.org/10.1155/2020/5901432.
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For high-end CNC machine tools, the stiffness of the spindle system is one of the most important performance indicators. In this paper, the hydrostatic motorized spindle system of a grinding machine is taken as the research object, and a two-degree-of-freedom stiffness model of the spindle system considering rotor swing is proposed. The stiffness of the spindle system under different excitation frequencies is analyzed, and the contributions of the stiffness of two bearings to the stiffness of the spindle system are evaluated. The vibration test on the spindle system is implemented through the hammering method. The vibration responses of the spindle system are obtained, and the stiffness of the spindle system is identified. The results show that the test results of the stiffness of the spindle system are in good agreement with the theoretical calculation, with an average error of about 14.21%. The research in this paper can provide theoretical and data support for bearing design and stiffness evaluation of a hydrostatic spindle system.
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Gaber, Omar, and Seyed M. Hashemi. "On the Free Vibration Modeling of Spindle Systems: A Calibrated Dynamic Stiffness Matrix." Shock and Vibration 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/787518.
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The effect of bearings on the vibrational behavior of machine tool spindles is investigated. This is done through the development of a calibrated dynamic stiffness matrix (CDSM) method, where the bearings flexibility is represented by massless linear spring elements with tuneable stiffness. A dedicated MATLAB code is written to develop and to assemble the element stiffness matrices for the system’s multiple components and to apply the boundary conditions. The developed method is applied to an illustrative example of spindle system. When the spindle bearings are modeled as simply supported boundary conditions, the DSM model results in a fundamental frequency much higher than the system’s nominal value. The simply supported boundary conditions are then replaced by linear spring elements, and the spring constants are adjusted such that the resulting calibrated CDSM model leads to the nominal fundamental frequency of the spindle system. The spindle frequency results are also validated against the experimental data. The proposed method can be effectively applied to predict the vibration characteristics of spindle systems supported by bearings.
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Li, Chang He, Wei Ping Mao, and Yu Cheng Ding. "Numerical Investigation into Spindle System Stiffness of High-Speed Grinder." Key Engineering Materials 487 (July 2011): 490–94. http://dx.doi.org/10.4028/www.scientific.net/kem.487.490.
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This study was focused on the theoretical modeling and numerical investigation about the dynamic and static stiffness of spindle system of high speed grinder. The moment balance and the transition matrix, the state vector, field matrix of spindle system of high speed grinder were analyzed and deduced. The theoretical models about dynamic and static stiffness were established using the transfer matrix method. The numerical results showed that increas of the preload could result in the improvement of static stiffness of spindle end within the range of its working speed; the reduction of front overhang length would improve the stiffness of spindle end, as well as the dynamic stiffness of spindle at the working speed; the stiffness of spindle end decreased with the increase of speed with different bearing spans within the range of working speed of spindle.
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Lin, Shen Yung, C. T. Chung, R. W. Chang, and C. K. Chang. "Effect of the Bearing Preload on the Characteristics of the Spindle Stiffness." Key Engineering Materials 419-420 (October 2009): 9–12. http://dx.doi.org/10.4028/www.scientific.net/kem.419-420.9.
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The main objective of this study is to investigate the effect of bearing preloads on the characteristics of spindle stiffness. Finite element model for spindle-bearing system is established enabling the variation of spindle stiffness calculations under different bearing preloads. On the other hand, the spindle stiffness may also be obtained from the experiment and its result may be utilized to validate the numerical calculations. The front-end section of spindle is acted by poise weights at different directions, and their corresponding deformations are measured through dial indicator. Three bearing preload conditions, i.e. light, medium and heavy preloads are selected, which are imposed on the bearing to investigate the spindle stiffness variation, respectively. In addition, the effects of the geometrical parallelism error at the end surfaces of spacer due to the manufacturing tolerance or some imperfection on the spindle stiffness are studied. Finally, the impact test on the spindle-bearing body is performed by hammer and the corresponding vibration signal on the spindle surfaces is acquired by accelerometer. The spindle stiffness may be reflected in the other manner through the signals processing by spectrum analysis.
Dissertations / Theses on the topic "Spindle stiffness"
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Chaigne, Agathe. "Cortical stiffness : a gatekeeper for spindle positioning in mouse oocytes." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066288/document.
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Les divisions méiotiques sont très asymétriques en taille et génèrent une très grosse cellule, l'ovocyte, et deux petites cellules, les globules polaires. Cette asymétrie est permise par la migration du fuseau lors de la première division jusqu'au cortex le plus proche. Cette migration ne dépend pas des microbutules mais de la Myosin-II et d'un réseau de filaments d'actine nucléé par la coopération des nucléateurs de filaments droits Formin-2 et Spire1/2. Des observations préliminaires effectuées au laboratoire ont décrit un épaississement du cortex d'actine pendant la migration du fuseau, mais pourtant il avait été montré que la tension corticale, un paramètre décrivant la rigidité de l'ovocyte, diminue pendant la migration du fuseau. J'ai montré que cet épaississement est indispensable à la migration du fuseau et est nucléé par le nucléateur de filaments branchés Arp2/3, sous le contrôle de la voie Mos/MAPK. De plus, il provoque la diminution de la tension corticale en délocalisant la Myosin-II, ce qui est indispensable à la migration du fuseau. Finalement, j'ai montré que le chute de tension est un mécanisme d'amplification du déséquilibre des forces présent initialement (grâce au léger décentrage du noyau) qui déclenche la migration du fuseauMeiotic divisions are highly asymmetric divisions in size, generating a big cell, the oocyte, and two tiny cells, the polar bodies. This asymmetry is ensured by the migration of the first meiotic spindle to the closest cortex. This migration does not depend on microtubules but on Myosin-II and an F-actin meshwork nucleated by cooperation of straight filament nucleators Formin-2 and Spire1/2. Preliminary studies in the lab described a thickening of the F-actin cortex during spindle migration, but paradoxically cortical tension, a physical parameter describing the stiffness of the cell, drops during spindle migration. I have shown that this thickening is required for spindle migration and nucleated by the branched actin nucleator Arp2/3, under the control of the Mos/MAPK pathway. Furthermore, it promotes the decrease in cortical tension by triggering the delocalization of Myosin-II from the oocyte cortex, which is crucial for spindle migration. Finally, I have shown that the drop in cortical tension is an amplificatory mechanism to the initial unbalance of forces (due to a slight off-centered position of the nucleus) triggering the motion of the spindle
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Sovadina, František. "Návrh vřeteníku soustruhu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-443734.
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The thesis deals with the design and construction of headstocks of a turning centre. The aim is to design a spindle with an output of 20 kW and a maximum speed of 5000 1/min. The research part of the thesis is focused on the description of the basic parameters of the headstock and turning centres needed for the construction of the headstock and contains an analysis of the available spindles on the market. The next part of the thesis deals with the selection and calculation of cutting conditions and the necessary parameters. Analytical calculations are then verified using FEM analysis. At the end of the thesis, a 3D model was developed and headstock drawing documentation.
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Laguna, Serrano Sergio. "Machining System Measurement and Modelling." Thesis, KTH, Industriell produktion, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-226333.
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Machine tools need to be tested to check they behave correctly while machining. A bigger production (capacity), improving the accuracy in final products (quality) or reducing costs are some of the main goals. Reducing the maintenance of the machines, their nonproductive time and a higher quality of the final parts, have a strong influence in the costs. Even machines built to the same specification present different properties and behaviours, which leads into a reduction of the flexibility when it comes to move operations among them. This study is focused on the measurement and modelling of four machine tools (M1, M2, M3 and M4), with same specifications, from the static point of view. Methods used to measure all these properties are the circular tests under loaded conditions, with the device Loaded Double Ball Bar (LDBB), which measures positional accuracy and static stiffness. Different pressures (0.5, 1, 3, 5, 6, 7 bar) and locations for the LDBB have been used. After the tests were performed, all the machines shown good properties with the detail of M4, which had a lower stiffness than the other three ones due to its table attachments.Maskinverktyg måste testas för att kontrollera att de beter sig korrekt vid bearbetning. En större produktion (kapacitet), förbättra noggrannheten i slutprodukterna (kvalitet) eller sänka kostnaderna är några av huvudmålen. Att minska underhållet av maskinerna, deras icke-produktiva tid och en högre kvalitet på de slutliga delarna har ett starkt inflytande i kostnaderna. Även maskiner konstruerade för samma specifikation presenterar olika egenskaper och beteenden, vilket leder till en minskning av flexibiliteten när det gäller att flytta verksamheten bland dem. Denna studie är inriktad på mätning och modellering av fyra verktygsmaskiner (M1, M2, M3 och M4), med samma specifikationer, ur statisk synvinkel. Metoder som används för att mäta alla dessa egenskaper är de cirkulära testerna under laddade förhållanden, med enheten Loaded Double Ball Bar (LDBB), som mäter positionsnoggrannhet och statisk styvhet. Olika tryck (0,5, 1, 3, 5, 6, 7 bar) och platser för LDBB har använts. Efter testerna visade alla maskiner goda egenskaper med detaljerna i M4, som hade en lägre styvhet än de andra tre på grund av dess bordsfästanordningar.
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Dodgen, Eric Ray. "Spinal Implant with Customized and Non-Linear Stiffness." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2699.
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There is a need for spinal implants that have nonlinear stiffness to provide stabilization if the spine loses stiffness through injury, degeneration, or surgery. There is also a need for spinal implants to be customizable for individual needs, and to be small enough to be unobtrusive once implanted. Past and ongoing work that defines the effects of degeneration on the torque rotation curve of a functional spinal unit (FSU) were used to produce a spinal implant which could meet these requirements. This thesis proposes contact-aided inserts to be used with the FlexSuRe™ spinal implant to create a nonlinear stiffness. Moreover, different inserts can be used to create customized behaviors. An analytical model is introduced for insert design, and the model is verified using a finite element model and tests of physical prototypes both on a tensile tester and cadaveric testing on an in-house spine tester. Testing showed the inserts are capable of creating a non-linear force-deflection curve and it was observed that the device provided increased stiffness to a spinal segment in flexion-extension and lateral-bending. This thesis further proposes that the FlexSuRe™ spinal implant can be reduced in size by joining LET joint geometries in series in a serpentine nature. An optimization procedure was performed on the new geometry and feasible designs were identified. Moreover, due to maintaining LET joint geometry, the contact-aided insert could be implemented in conjunction with this new device geometry.
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Mirbagheri, M. Mehdi (Mohammad Mehdi). "Intrinsic and reflex stiffness in normal & spastic spinal cord injured subjects." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=36823.
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The contributions of stretch reflexes to overall joint stiffness are unknown in normal and pathological function. The main reason for this is difficulty in distinguishing the mechanical contributions of the two mechanisms. We used a new non-linear system identification technique to achieve this and address three specific objectives.First, we identified intrinsic and reflex contributions to dynamic ankle stiffness over a wide range of tonic voluntary contraction levels and ankle positions in healthy human subjects (normals). Intrinsic and reflex dynamic stiffness were strongly modulated with operating points; reflex mechanisms made their largest relative contribution to ankle stiffness at low levels of contraction and near the mid-positions. In some cases, reflexes contributed significantly to overall torque indicating that stretch reflexes have a potential to play a significant role in control of posture and movement.
Second, we examined the nature and origin of mechanical abnormalities associated with spasticity in chronic spinal cord injured subjects (SCIs). Reflex and intrinsic stiffness were larger in SCIs than normals. The magnitude and relative size of the changes were strongly dependent on joint position and contraction state. Overall joint stiffness was abnormally and significantly high in SCIs and stretch reflexes contributed strongly to it.
Third, we explored the effects of long-term FES-assisted walking on intrinsic and reflex dynamic stiffness in SCIs. Both reflex and intrinsic stiffness decreased substantially following long-term (>16 months) FES-assisted walking. The results indicate that this rehabilitation approach may cause spastic joint mechanics to become closer to normal behavior, and consequently could be useful for treatment as well as restoring function.
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Moorhouse, Kevin Michael. "Role of Intrinsic and Reflexive Dynamics in the Control of Spinal Stability." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/29265.
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Spinal stability describes the ability of the neuromuscular system to maintain equilibrium in the presence of kinematic and control variability, and may play an important role in the etiology of low-back disorders (LBDs). The primary mechanism for the neuromuscular control of spinal stability is the recruitment and control of active paraspinal muscle stiffness (i.e., trunk stiffness). The two major components of active muscle stiffness include the immediate stiffness contribution provided by the intrinsic stiffness of actively contracted muscles, and the delayed stiffness contribution provided by the reflex response. The combined behavior of these two components of active muscle stiffness is often referred to as "effective stiffness".
In order to understand the neuromuscular control of spinal stability, stochastic system identification methods were utilized and nonparametric impulse response functions (IRFs) calculated in three separate studies in an effort to:
1) Quantify the effective dynamics (stiffness, damping, mass) of the trunk
Nonparametric IRFs were implemented to estimate the dynamics of the trunk during active voluntary trunk extension exertions. IRFs were determined from the movement following pseudo-random stochastic force disturbances applied to the trunk. Results demonstrated a significant increase in effective stiffness and damping with voluntary exertion forces.
2) Quantify the reflex dynamics of the trunk
Nonparametric IRFs were computed from the muscle electromyographic (EMG) reflex response following a similar pseudo-random force disturbance protocol. Reflexes were observed with a mean response delay of 67 msec. Reflex gain was estimated from the peak of the IRF and increased significantly with exertion effort.
3) Separate the intrinsic and reflexive components of the effective dynamics and determine the relative role of each in the control of spinal stability.
Both intrinsic muscle and reflexive components of activation contribute to the effective trunk stiffness. To evaluate the relative role of these components, a nonlinear parallel-cascade system identification procedure was used to separate the intrinsic and reflexive dynamics. Results revealed that the intrinsic dynamics of the trunk alone can be insufficient to counteract the destabilizing effects of gravity. This illustrates the extreme importance of reflexive feedback in the maintenance of spinal stability and warrants the inclusion of reflexes in any comprehensive trunk model.Ph. D.
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Zaragoza-Rivera, Yadetsie Nichole. "Pediatric Cervical Spine Range of Motion, Strength, and Stiffness in the Sagittal and Coronal Planes." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1587411565508067.
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Dmowski, Jan. "Design and evaluation of a non-invasive spinal indentation device for assessing stiffness of human musculoskeletal system." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0017/MQ47979.pdf.
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Lee, Patrick James. "Low Back Biomechanical Analysis of Isometric Pushing and Pulling Tasks." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/30835.
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Few studies have investigated the neuromuscular recruitment and stabilizing control of the spine during pushing and pulling exertions. Past theoretical investigation suggest that co-contraction of the of the paraspinal muscles is necessary to stabilize the spine during pushing exertions. We hypothesized greater levels of co-contraction during pushing exertions. Co-contraction of trunk musculature was quantified during isometric pushing and pulling tasks. The mean value of co-contraction during pushing was two-fold greater (p < 0.01) than during extension.
Co-contraction has been shown to increase the stiffness of the ankle but this effect has not been demonstrated in the trunk. Trunk stiffness was measured as a function of co-activation during extension exertions. Results demonstrate trunk stiffness was significantly (p < 0.01) greater with co-activation.
Trunk stiffness was calculated during isometric pushing and pulling exertions. We hypothesized trunk stiffness would be greater during pushing tasks due to increased levels of co-contraction to maintain stability of the spine. Results demonstrate trunk stiffness was significantly (p < 0.05) greater during pushing compared to pulling exertions.
Results suggest that trunk isometric pushing tasks require more co-contraction than pulling tasks enable to maintain spinal stability. Greater levels of co-contraction during pushing exertions caused trunk stiffness to be greater during pushing compared to pulling tasks. Results may indicate greater risk of spinal instability from motor control error during pushing tasks than pulling exertions. Future studies need to consider co-contraction and neuromuscular control of spinal stability when evaluating the biomechanical risks of pushing and pulling tasks.Master of Science
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Odet, Margot. "Étude biomécanique d’une suspension implantable pour la préservation des disques intervertébraux dans le traitement des scolioses infantiles." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1135/document.
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La scoliose infantile est une déformation rachidienne évolutive survenant chez l'enfant de moins de 3 ans. La technique de correction la plus répandue actuellement est celle des « tiges de croissance ». Cependant, la rigidité du matériel provoque la dégénérescence des disques intervertébraux, ce qui di-minue l'efficacité du traitement. Des études récentes ont montré l'effet bénéfique d'implants flexibles sur les disques. Notre équipe a donc développé le concept d'une suspension implantable qui permet de garder la mobilité axiale des segments instrumentés, associé à un nouveau système de fixation rotulée. Cepen-dant, quelle valeur de raideur permet de préserver les disques tout en corrigeant efficacement la sco-liose ? Cette thèse a donc pour objectifs de démontrer l'intérêt d'une suspension pour les disques inter-vertébraux et d'obtenir des informations quantifiables sur la valeur optimale de raideur. Pour cela des prototypes de suspension avec fixation rotulée, implantables chez le mammifère quadrupède et l'Homme, ont été développés afin d'étudier in vivo et in silico plusieurs gammes de flexibilité. Une étude in vivo sur chèvres adultes saines a été menée pour tester ces prototypes pour 2 raideurs différentes. L'état des disques intervertébraux après 6 mois a été évalué par IRM et par coupes histologiques. En parallèle la biomécanique d'un rachis humain sain puis scoliotique, instrumenté avec différents disposi-tifs (tiges classiques, suspensions, avec ou sans rotules), a été étudiée avec un modèle numérique mul-ti-corps rigides, préalablement validé par comparaison avec des données in vitro de la littérature. Les résultats de l'étude in vivo n'ont pas montré de différence significative entre les différentes instrumentations testées. Un temps d'essai plus long semble nécessaire pour voir apparaître la dégéné-rescence discale. Les simulations numériques ont montré une nette amélioration de la mobilité des segments ins-trumentés avec une suspension rotulée. La majorité de la mobilité est cependant assuré par le nouveau système de fixation et non par la présence d'une plus grande souplesse axiale. La suspension permet néanmoins un gain supplémentaire pour certains mouvements du rachis. Aucune différence significative n'a été constatée entre les 2 valeurs de raideurs étudiées. La présence de fixations rotulée diminue par contre fortement la correction obtenue lors des simulations de chirurgie de distraction. La suspension seule présente un intérêt certain lors de la correc-tion en diminuant les efforts transmis au matériel. Les développements futurs s'orienteraient donc vers une suspension combinée à des fixations rotulées présentant également des raideurs en rotation pour conserver correction et mobilitéInfantile scoliosis is a progressive spinal deformity occurring in children under 3 years-old. The most common currently correction technic is the "growing rods" one. However, the implant rigidity causes intervertebral discs degeneration, which decreases the treatment efficiency. Recent studies have shown the benefic effect of flexible implants on discs. Our team has developed the concept of an implantable suspension that keeps the axial mobility of the instrumented segments, associated with a new fastening ball joint system. However, which is the stiffness value that preserves discs while correcting scoliosis? This thesis goal is to demonstrate the effectiveness of a suspension device for preserving inter-vertebral discs health and obtain quantifiable information on the optimum stiffness value. Prototype suspensions with ball joint fastenings, implantable in quadruped mammals and humans, have been de-veloped to study several ranges of stiffness values in vivo and in silico. An in vivo study on healthy adult goats was conducted to test these prototypes for two different stiffness values. The intervertebral discs health after 6 months was evaluated by MRI and histological sections. In parallel the biomechanics of a human spine was studied with a rigid multi-body numerical model previously validated against in vitro literature data. Healthy and scoliosis subjects instrumented with different devices (traditional rods, sus-pensions, with or without the ball) were modeled. The results of the in vivo study showed no significant difference between the several instrumen-tations. A longer test time seems necessary to observe the onset of disc degeneration. Numerical simulations have shown a marked mobility improvement for the segments in the in-strumented area with a suspension device associated with a ball joint system. However, the majority of the mobility is provided by the new fixing system and not by a greater axial flexibility. The suspension still allows additional gain for certain spine movements. No significant differences were found between the two studied stiffness values. The presence of a ball joint fastening decreases strongly the correction obtained during surgery distraction simulations. The suspension has an interest during correction by reducing the forces trans-mitted to the material when used alone. Future developments thus would lead to a suspension device associated with ball joint fasten-ings that also have rotational stiffness to keep both good scoliosis correction and segments mobility
Books on the topic "Spindle stiffness"
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van Gaalen, Floris, Désirée van der Heijde, and Maxime Dougados. Diagnosis and classification of axial spondyloarthritis. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780198734444.003.0003.
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Axial spondyloarthritis (axSpA) is a potentially disabling chronic inflammatory disease affecting the spine and sacroiliac (SI) joints. Lead symptoms are chronic back pain and stiffness. The disease is called radiographic axSpA or ankylosing spondylitis (AS) when, on plain radiographs, bone changes consistent with sacroiliitis are present. When no evidence of sacroiliitis is seen on radiographs, it is called non-radiographic axSpA. In such cases, diagnosis is made based on evidence of active inflammation of SI joints on magnetic resonance imaging (MRI) and clinical and laboratory features, or a combination of clinical and laboratory features only. Apart from affecting the spine and SI joints, axSpA may involve peripheral joints (e.g. knee, ankle) and manifest in extra-articular manifestations, for example uveitis, psoriasis, and inflammatory bowel disease. In this chapter, diagnosis and classification of axSpA is discussed, including use of MRI in detecting sacroiliitis and the difference between clinical diagnosis and disease classification.
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Siebert, Stefan, Sengupta Raj, and Alexander Tsoukas. Inflammatory back pain. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780198755296.003.0006.
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Inflammatory back pain (IBP) refers to a collection of symptoms that may help identify patients with possible inflammatory spinal disease. A number of criteria sets have been proposed for IBP, which share common features such as: onset of symptoms aged <40 years, alternating buttock pain, improvement with exercise, worsening with rest, gradual onset, early morning stiffness, and improvement with NSAIDs. The IBP criteria were initially developed and validated in patients with ankylosing spondylitis, but have subsequently been shown to perform similarly in patients with axial spondyloarthritis (axSpA). The Berlin criteria demonstrated the highest specificity (84%) and the Calin criteria the highest sensitivity (92%). IBP criteria have been used in primary and secondary care referral strategies to facilitate the identification of patients with potential axSpA. It is important to note that IBP does not equate to a diagnosis of axSpA and many patients with IBP will not have axSpA.
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Buchanan, Elaine, and Chris Lavy. Low back pain. Edited by Patrick Davey and David Sprigings. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780199568741.003.0064.
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Low back pain (LBP) is pain arising from the structures of the lumbar spine, including joints, discs, connective tissue, and nerves. Symptoms include pain and, muscle tightness or stiffness, with or without referral of pain to the legs. Most (95%) of LBP is managed in primary care; the rest is managed in secondary care. LBP affects nearly everyone at some point in their life and has an annual prevalence of around 40%. It is less common in children but from age 16 onwards the point prevalence for all age groups is around 25%. Many experience milder persisting symptoms interspersed with exacerbations, and 7% of adults have persisting LBP, which restricts function. This chapter discusses LBP, including definitions, differential diagnosis, context, approach to diagnosis, specific clues to the diagnosis, key diagnostic tests, treatment and therapy, prognosis, and how to handle uncertainty in the diagnosis of the symptom.
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Siebert, Stefan, Sengupta Raj, and Alexander Tsoukas. What are axial spondyloarthritis and ankylosing spondylitis? Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780198755296.003.0001.
Full textAbstract:
Ankylosing spondylitis (AS) is a chronic inflammatory arthritis affecting mainly the sacroiliac joints and spine, resulting in pain, stiffness, and reduced movement. AS has a major negative impact on patients’ quality of life. AS is part of a larger group of related spondyloarthritis (SpA) conditions and patients with AS often have extra-articular manifestations of these conditions. Over the past decade, there have been major advances in the understanding of the genetics and pathophysiology of the disease. Advances in imaging have allowed patients to be diagnosed without having to develop the radiographic structural damage that characterize AS, resulting in the concept of axial spondyloarthritis (axSpA). Together with the development of highly effective TNF inhibitors, these advances have transformed the management and outlook of patients with this condition. It is hoped that further advances in diagnosis, assessment and treatment of axSpA will lead to further progress in future.
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Siebert, Stefan, Raj Sengupta, and Alexander Tsoukas, eds. Axial Spondyloarthritis. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780198755296.001.0001.
Full textAbstract:
Ankylosing spondylitis (AS) is a chronic inflammatory arthritis affecting mainly the sacroiliac joints and spine, resulting in pain, stiffness, and reduced movement. Over the past decade there have been major advances in many aspects of the disease, including a broadening of the disease description to axial spondyloarthritis (axSpA). While the many advances have transformed the lives of patients with axSpA, they have also increased complexity for non-specialists in this area. This handbook contains a timely update of the key developments and current state of play in axSpA. It is intended primarily for the many healthcare professionals who encounter patients with this condition, in both primary and secondary care settings. It will also be of interest to the wider medical and research community.The handbook is written by rheumatologists with active research programmes and clinical expertise in these conditions. The topics covered include: • the clinical features • extra-articular manifestations and complications • the impact on patients’ lives • the major advances in genetics and pathogenesis • imaging advances • classification criteria and diagnosis (and the important differences between these) • treatment advances (particularly TNF inhibitors and upcoming biologics)
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Sieper, Joachim. Ankylosing spondylitis. Oxford University Press, 2013. http://dx.doi.org/10.1093/med/9780199642489.003.0113.
Full textAbstract:
Ankylosing spondylitis (AS) is a chronic inflammatory disease predominantly of the sacroiliac joint (SIJ) and the spine. It starts normally in the second decade of life and has a slight male predominance. The prevalence is between 0.2 and 0.8% and is strongly dependent on the prevalence of HLA B27 in a given population. For the diagnosis of AS, the presence of radiographic sacroiliitis is mandatory. However, radiographs do not detect active inflammation but only structural bony damage. Most recently new classification criteria for axial spondyloarthritis (SpA) have been developed by the Assessement of Spondylo-Arthritis international Society (ASAS) which cover AS but also the earlier form of non-radiographic axial SpA. MRI has become an important new tool for the detection of subchondral bone marrow inflammation in SIJ and spine and has become increasingly important for an early diagnosis. HLA B27 plays a central role in the pathogenesis but its exact interaction with the immune system has not yet been clarified. Besides pain and stiffness in the axial skeleton patients suffer also from periods of peripheral arthritis, enthesitis, and uveitis. New bone formation as a reaction to inflammation and subsequent ankylosis of the spine determine long-term outcome in a subgroup of patients. Currently only non-steroidal anti-inflammatory drugs (NSAIDs) and tumour necrosis factor (TNF) blockers have been proven to be effective in the medical treatment of axial SpA, and international ASAS recommendations for the structured management of axial SpA have been published based on these two types of drugs. Conventional disease-modifying anti-rheumatic drugs (DMARDs) such as methotrexate are not effective.
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Sieper, Joachim. Axial spondyloarthropathies. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199642489.003.0113_update_003.
Full textAbstract:
Axial spondyloarthritis (axSpA) is a chronic inflammatory disease predominantly of the sacroiliac joint (SIJ) and the spine. It starts normally in the second decade of life and has a slight male predominance. The prevalence is between 0.2% and 0.8% and is strongly dependent on the prevalence of HLA-B27 in a given population. AxSpA can be split in patients with radiographic axSpA (also termed ankylosing spondylitis (AS)) and in patients with non-radiographic axSpA (nr-axSpA). For the diagnosis of AS, the presence of radiographic sacroiliitis is mandatory. However, radiographs do not detect active inflammation but only structural bony damage. Most recently new classification criteria for axSpA have been developed by the Assessment of Spondylo-Arthritis International Society (ASAS) which cover AS but also the earlier form of nr-axSpA. MRI has become an important new tool for the detection of subchondral bone marrow inflammation in SIJ and spine and has become increasingly important for an early diagnosis. HLA-B27 plays a central role in the pathogenesis but its exact interaction with the immune system has not yet been clarified. Besides pain and stiffness in the axial skeleton patients suffer also from periods of peripheral arthritis, enthesitis, and uveitis. New bone formation as a reaction to inflammation and subsequent ankylosis of the spine determine long-term outcome in a subgroup of patients. Currently only non-steroidal anti-inflammatory drugs (NSAIDs) and tumour necrosis factor (TNF) blockers have been proven to be effective in the medical treatment of axial SpA, and international ASAS recommendations for the structured management of axial SpA have been published based on these two types of drugs. Conventional disease-modifying anti-rheumatic drugs (DMARDs) such as methotrexate are not effective.
Book chapters on the topic "Spindle stiffness"
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Bhardwaj, Vibish S., Ramesh H. Aralaguppi, Ashok N. Badhe, Bhargav, and Arun R. Rao. "Study and Estimation of Static Stiffness of Machine Tool Spindle." In Lecture Notes on Multidisciplinary Industrial Engineering, 143–52. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-3254-2_14.
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Aralaguppi, Ramesh H., K. B. Siddesh, and Ashok N. Bade. "Joint Stiffness Estimation Between Spindle-Tool Holder by Considering Clamping Forces." In Lecture Notes in Mechanical Engineering, 593–607. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-0550-5_59.
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Bouaziz, Amel, Maher Barkallah, Slim Bouaziz, Jean-Yves Cholley, and Mohamed Haddar. "Non-linear Stiffness and Damping Coefficients Effect on a High Speed AMB Spindle in Peripheral Milling." In Mechatronic Systems: Theory and Applications, 99–110. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-07170-1_10.
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Melnyk, Oleksandr, Larysa Hlembotska, Nataliia Balytska, Viacheslav Holovnia, and Mykola Plysak. "The Imitation Study of Taper Connections Stiffness of Face Milling Cutter Shank Using Machine Spindle in the SolidWorks Simulation Environment." In Lecture Notes in Mechanical Engineering, 602–12. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-22365-6_60.
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Pham, Van-Hung, Manh-Toan Nguyen, and Tuan-Anh Bui. "Improve the Loading Capacity and Stiffness of Hydrostatic Spindle Medium Sized Circular Grinding Machines Based on Simulation and Geometric Parameters of the Bearing." In Springer Proceedings in Materials, 551–58. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-45120-2_45.
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Ebara, Sohei, Masao Tanaka, Yoshiharu Morimoto, Takeo Harada, Noboru Hosono, Kazuo Yonenobu, and Keiro Ono. "Intraoperative Measurement of Lumbar Spinal Stiffness." In Lumbar Fusion and Stabilization, 45–53. Tokyo: Springer Japan, 1993. http://dx.doi.org/10.1007/978-4-431-68234-9_6.
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Freudiger, Stefan. "Biomechanical Engineering in Choice of Different Stiffness Material." In Cervical Spine, 173–78. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-21608-9_14.
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Sommerich, Robert, Melissa (Kuhn) DeCelle, and William J. Frasier. "Mechanical Implant Material Selection, Durability, Strength, and Stiffness." In Handbook of Spine Technology, 1–12. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-319-33037-2_30-1.
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Sommerich, Robert, Melissa (Kuhn) DeCelle, and William J. Frasier. "Mechanical Implant Material Selection, Durability, Strength, and Stiffness." In Handbook of Spine Technology, 151–62. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-319-44424-6_30.
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Shah, V. G., M. C. Anderson, D. A. Lissy, and C. J. Lissy. "Fixture Variations When Evaluating ASTM F1717 Construct Stiffness: Pin Diameter and Material." In Static and Dynamic Spinal Implants: Are We Evaluating Them Appropriately?, 273–86. 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959: ASTM International, 2011. http://dx.doi.org/10.1520/stp49415t.
Full textConference papers on the topic "Spindle stiffness"
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Wan, Shaoke, Jun Hong, Wenjun Su, Xiaohu Li, Yanhui Sun, and Wei Chen. "Measurement of Dynamic Performances of High-Speed Rotating Spindle by Non-Contact Electromagnetic Loading Device." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-70301.
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When spindle rotates, the stiffness and natural frequency that reflect the dynamic performances of spindle system, vary with different rotating conditions. Therefore, the measurement of stiffness and natural frequency is highly needed. However, it is difficult to apply excitation to the rotating spindle during the measurement. In this paper, a non-contact electromagnetic loading device is developed to provide desirable excitation for the measurement. Next, an experimental spindle test rig with constant pressure preload is established. With the help of the proposed loading device, stiffness and natural frequency of the experimental spindle at different rotating states are measured. Finally, the effects of rotation speed and temperature on the natural frequency and stiffness of spindle are discussed based on the measurement results. The results show that the rotation speed and temperature have the similar influence trend on the experimental spindle’s softening.
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Noel, David, Mathieu Ritou, Sebastien Le Loch, and Benoit Furet. "Bearings Influence on the Dynamic Behavior of HSM Spindle." In ASME 2012 11th Biennial Conference on Engineering Systems Design and Analysis. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/esda2012-82563.
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The aeronautic industry requires high speed and high power spindles to obtain high material removal rates during long rough milling operations. The weakness of HSM spindle is the bearings, although high precision hybrid ball bearings have been developed to achieve this critical application. Inadequate use of spindles inevitably leads to shortened lifetimes. Choosing the operating conditions is a required step before machining applications. It can be achieved through either experimental tests or numerical modeling that leads to stability lobe diagrams. Stability of cuts relies on the dynamic behavior of the spindle, which is particularly due to the eigenfrequencies of the tool-shaft assembly. The frequencies depend on bearing stiffness that can change under operating conditions. That is why the impact of cutting conditions and bearing parameters on its stiffness are studied in the paper. A five degrees of freedom model of angular ball bearing is briefly presented. A complete bearing model is introduced. The originality of the approach is the complete technological modeling, notably of the radial expansions of inner and outer rings of bearing. A non-linear expression is established from continuum mechanics model. The influence of geometry of bearing, operating conditions and design parameters of spindle on the bearing stiffness are established and analysed. Then, modal analyses of the tool-spindle assembly are carried out in relation to the varying bearing stiffness. Finally, significance of the approach is demonstrated through the analyses of Frequency Response Function.
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Nakao, Yohichi, Kohei Yamada, and Kenji Suzuki. "Design of Spindle Supported by High Stiffness Water Hydrostatic Thrust Bearing." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-62729.
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A precision spindle is a key component of the ultra-precision machine tools that are used for machining precision molds for producing various lenses and other precise parts. The machining accuracy required for the parts now reaches several tens of nanometers. In order to achieve the desired machining accuracy, the precise spindle system with high stiffness bearings is inevitably needed for the ultra-precision machine tools. The paper thus deals with a design of a spindle supported by water hydrostatic bearings. An objective of the study is to design the precision spindle supported by the water hydrostatic bearings with the bearing stiffness of 1 kN/μm. Thus the paper presents the design procedure of the hydrostatic thrust bearings. In particular, the design of the bearing restrictors is introduced. The characteristics of water hydrostatic thrust bearings of the designed spindle are investigated theoretically. The influences of the gap sizes and the supply water pressure on the bearing stiffness are given. It is indicated that the bearing stiffness of 1 kN/μm can be obtained by the spindle design. Structure and materials of the developed spindle are also introduced.
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Chen, C. H., K. W. Wang, and Y. C. Shin. "An Integrated Approach Toward the Dynamic Analysis of High-Speed Spindles: Part I — System Model." In ASME 1993 Design Technical Conferences. American Society of Mechanical Engineers, 1993. http://dx.doi.org/10.1115/detc1993-0210.
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Abstract Experimental evidence [Shin, 1992] has shown that the natural frequencies of high speed spindles with angular contact ball bearings decrease with increasing rotational speed. A recent study [Wang, et al., 1991] illustrated that this phenomenon is caused by stiffness change of the bearings. A simplified approximation was used in the analysis to examine the bearing radial stiffness at high speeds. While the investigation explained the experimental observations in a qualitative sense, the analytical results so far are not sufficient to quantitatively describe the spindle behavior under high speed operations due to the approximations made in the modeling process. This paper presents an integrated approach toward the modelling of flexible spindles with angular contact ball bearings from basic principles. The local dynamics of the bearings are coupled with the global shaft motion. The model derived includes both the longitudinal and transverse vibrations of the shaft interacting with the nonlinear bearings. The influences of shaft speed on the bearing stiffness matrix and the system frequencies have been studied. It is shown that the spindle dynamic behavior can vary substantially as speed increases due to the bearing gyroscopic moment and centrifugal force. These effects have been ignored in most of the previous spindle models. Lab tests were conducted to validate the model. The analytical predictions are quantitatively verified by the experimental results.
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Adams, Maurice L., and Michael A. Laurich. "Design, Analysis and Testing of an Inside-Out Tilting-Pad Journal Bearing With Real-Time Controllable Preload and Stiffness." In World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-63067.
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It has recently been shown that high-speed grinding can be applied to the finishing of ceramics with considerable improvements in throughput and quality. This will require new high-speed high-power centerless grinding spindles (7,000 RPM, 50 HP), with high-stiffness of three hundred and fifty million Newtons/meter (2 million lb/in). To meet these requirements a novel inside-out, three-pad, pivoting-pad oil-fed hydrodynamic journal bearing has been devised, built and tested. One of the three pad’s pivot point is supported by a hydraulically-actuated radial-motion loading piston. This provides real-time controllable preload to all three bearing pads, thereby controlling bearing stiffness, providing less-stiff spindle bearings for initial rough grinding and very high stiffness spindle bearings for precision finish grinding. Extensive bearing test data compare favorably with theoretically predicted bearing performance.
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Su, Wenjun, Shaoke Wan, Yanhui Sun, Jun Hong, and Xiaohu Li. "Contactless Measurement of Spindle Stiffness by Using Lateral Stator Magnetic Loader." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-70382.
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In this paper, a novel radial loading topology is proposed for various spindle test application where the space in the tool head is limited or the performance to the length is sensitive. The stator of the loading device grows in the lateral direction, allowing for a compact axial length design. Finite element analysis (FEA) is carried out and the device design is optimized for the specifications of a radial loading device for high speed spindle. Finally, the designed device were manufactured and tested. By using this magnet loader, measurement results are given and the effectiveness of the designed prototype has been verified.
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Gao, Siyu, Kai Cheng, and Hui Ding. "Multi-Physics Simulation Based Design and Analysis of a High Speed Aerostatic Spindle and its Performance Assessment." In ASME 2014 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/detc2014-34086.
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High speed aerostatic spindles operating at a speed up to 200,000 r/min are a complex product with a multi-physics nature resulted from embedded mechanical-thermal-fluidic-electromagnetic fields. It is much needed to have a comprehensive analysis on the multi-physic interactions within a high speed aerostatic spindle, which is essential for design of the spindles working at much higher speeds and accuracy in various increasingly stringent engineering conditions. This paper presents a multi-physics integrated modelling approach for design and analysis of the high speed aerostatic spindle, including thermal, electromagnetic, mechanical and fluidic analysis models. The heat source, heat transfer mechanism and heat sinks of the spindle system are comprehensively investigated. Furthermore, air film pressure distribution is studied to lead to optimal design and analysis of loading capacity and stiffness of the aerostatic bearings. The multi-physics modelling is implemented using the CFD-FEA integrated approach and validated experimentally. It is shown that the multi-physics integrated modelling is able to simulate the performance characteristics of the spindle system accurately.
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Matsubara, Masami, Takayuki Koizumi, Nobutaka Tsujiuchi, Fumiya Nakamura, and Koji Matsuyama. "Identification of Tire Equivalent Stiffness for Prediction of Vertical Spindle Forces." In 16th Asia Pacific Automotive Engineering Conference. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2011. http://dx.doi.org/10.4271/2011-28-0093.
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Noel, David, Sebastien Le Loch, Mathieu Ritou, and Benoit Furet. "HSM Spindle Model Updating With Physical Phenomena Refinements." In ASME 2013 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/detc2013-13141.
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The modeling of High Speed Machining (HSM) spindles is a complex task due to the numerous physical phenomena involved in the dynamic behavior. Modeling is still rarely used in the industry, although sophisticated research work has been achieved. The boundary conditions of rotor models, which correspond to the ball bearings, are crucial and difficult to define. Indeed, they affect the dynamic behavior of the rotor in a non-linear and sometimes in an unpredictable way. The aim of the paper is to determine a relevant spindle model, i.e. the adequate level of complexity. To do so, a dynamic bearing model is introduced and the axial model of a spindle is established in relation to the preloaded bearing arrangement. Then, the operating stiffness of the spindle has been obtained experimentally with a new specific device that applies axial load and measures the resulting displacement, whatever the spindle speed. The model updating with the experimental data combined to sensibility analysis have led to the model refinement with additional physical phenomena, in order to account for non-linearities observed experimentally. The parameters of the model are also identified experimentally. As a result, a relevant spindle model is obtained and validated by the good agreement between simulations and experiments.
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Harder, John E., and Jeffrey L. Stein. "A Thermal-Based Spindle Bearing Load Controller: Preliminary Experimental Evaluation." In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-32035.
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Thermally induced bearing loads are a serious problem for high-speed machining spindles used in metal cutting. Ideally, the bearing loads can be set to provide the necessary spindle stiffness to achieve the desired dynamic performance, while at the same time achieving long bearing life. Unfortunately, this is difficult to do because many process conditions affect these loads, sometimes in difficult to predict ways with significant degradation of spindle performance and life. The purpose of this paper is to describe a preliminary experimental evaluation of controlling bearing loads by controlling the heat generated by a thermal actuator placed around the spindle housing. A box spindle modified with an electric heating tape placed around its front ball bearings is used for this evaluation. The results show that significant control over the bearing load can be achieved for the conditions tested. However, it is discovered that asymmetrical placement of the heater with respect to the pair of back-to-back angular-contact bearings makes it difficult to regulate the loads on each bearing to the set point. Solutions to this problem are discussed and further research outlined. Nevertheless, the feasibility of the control of thermally induced bearing spindle loads with an externally mounted heater appears promising.