An aerodynamic bearing with adjustable geometry and self-lifting capacity. Part 1: Self-lift capacity by squeeze film

Ha, Da; Stolarski, T.A.; Yoshimoto, Shigeka

doi:10.1243/135065005x9682

Cited by 38 publications

(19 citation statements)

References 3 publications

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“…This finding can guide and optimize the design of NFAL platform to work in different frequency bands. This equation can provide an estimated levitation height of the object, the trend of the levitation curve is reasonable and corresponds to the theoretical results [7], 20] and is comparable with experimental results reported by Atherton et al [21] .…”

Section: ∫ ∫ ∫∫supporting

confidence: 89%

NFAL Prototype Design and Feasibility Analysis for Self-Levitated Conveying

Chang

Wei

Atherton

et al. 2016

Tribology Transactions

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：In order to avoid friction and scratching when conveying objects, a squeeze-film levitation prototype was designed to verify the feasibility. The modal shapes and the forced harmonic shapes of the prototype are obtained by an ANSYS coupled field computation with a ¼ symmetry model and the levitation capacity was assessed by the use of groups of simulation and physical testing. The simulation results show that the pure flexural and mixed flexural wave shapes with different wave number exist at specific frequencies. The amplitude of the central point of an aluminium plate having four piezo-electric discs glued to the bottom surface was simulated for a frequency spectrum. The experimental results confirm the theoretical results and the feasibility of the prototype, and also confirm that objects can be floated at several resonant frequencies under forced vibration conditions. The system provides the largest levitating capacity when both the piezo-electric disc and the plate resonances coincide.

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Section: ∫ ∫ ∫∫supporting

confidence: 89%

NFAL Prototype Design and Feasibility Analysis for Self-Levitated Conveying

Chang

Wei

Atherton

et al. 2016

Tribology Transactions

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“…Using these three design rules, a design of the squeeze film air journal bearing (Ha et al, 2005;Zhao and Wallaschek, 2009), as shown in Fig. 13, is proposed.…”

Section: Calculation Resultsmentioning

confidence: 99%

Study of design parameters for squeeze film air journal bearing – excitation frequency and amplitude

Wang

2011

Mech. Sci.

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Abstract. The paper presents a design of squeeze film air journal bearing based on the design rules derived from CFX and FEA simulation study of an air film in between two flat plates, one of which was driven in a sinusoidal manner. The rules are that the oscillation frequency should be at least 15 kHz and that the oscillation amplitude be as large as possible to ensure a greater film thickness and to allow the bearing to reach its stable equilibrium quickly. The proposed journal bearing is made from AL2024-T3, of 20.02 mm outer diameter, 600 mm length and 2 mm thickness. Three 20-mm long fins are on the outer surface of the bearing tube and are spaced 120• apart; three longitudinal flats are milled equi-spaced between the fins and two piezoelectric actuators are mounted lengthwise on each flat. Such a design produces a modal shape on the bearing tube which resembles a triangle. When excited in this mode at the frequency of 16.37 kHz, and a voltage of 75 V AC with 75 V DC offset acting on the piezoelectric actuators, the air gap underneath of the bearing tube behaves as a squeeze air film with a response amplitude of 3.22 µm. The three design rules were validated by experiments.

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“…Stolarski and Ha et al presented a new kind of ultrasonic journal bearing, which integrates ultrasonic levitation with hydrodynamic lubrication aimed at solving the wear problem of aerodynamic bearings in the starting or low-speed stage. The force required from one piezo-actuator to produce deformation of lobe depth of 3.5 μm was about 10 N [18][19][20]. Chao Wang proposed a tubular squeeze-film journal bearing.…”

Section: Structure and Operating Principlementioning

confidence: 99%

A Novel Noncontact Ultrasonic Levitating Bearing Excited by Piezoelectric Ceramics

Quan

Deng

et al. 2016

Applied Sciences

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A novel ultrasonic levitating bearing excited by three piezoelectric transducers is presented in this work. The transducers are circumferentially equispaced in a housing, with their center lines going through the rotation center of a spindle. This noncontact bearing has the ability to self-align and carry radical and axial loads simultaneously. A finite element model of the bearing is built in ANSYS, and modal analysis and harmonious response analysis are conducted to investigate its characteristics and driving parameters. Based on nonlinear acoustic theory and a thermodynamic theory of ideal gas, the radical and lateral load-carrying models are built to predict the bearing's carrying capacity. In order to validate the bearing's levitation force, a test system is established and levitating experiments are conducted. The experimental data match well with the theoretical results. The experiments reveal that the maximum radical and axial levitating loads of the proposed bearing are about 15 N and 6 N, respectively, when the piezoelectric transducers operate at a working frequency of 16.11 kHz and a voltage of 150 V p-p .

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An aerodynamic bearing with adjustable geometry and self-lifting capacity. Part 1: Self-lift capacity by squeeze film

Cited by 38 publications

References 3 publications

NFAL Prototype Design and Feasibility Analysis for Self-Levitated Conveying

NFAL Prototype Design and Feasibility Analysis for Self-Levitated Conveying

Study of design parameters for squeeze film air journal bearing – excitation frequency and amplitude

A Novel Noncontact Ultrasonic Levitating Bearing Excited by Piezoelectric Ceramics

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