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Shih-chieh Lin - One of the best experts on this subject based on the ideXlab platform.
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A Simulation Study for the Design of Membrane Restrictor in an Opposed-Pad HydroStatic Bearing to Achieve High Static Stiffness
MDPI AG, 2018Co-Authors: Ta-hua Lai, Shih-chieh LinAbstract:The effects of a membrane restrictor’s design parameters on the performance of a hydroStatic opposed-pad bearing are presented in this article. Compared to the single-pad bearing, the opposed-pad bearing can perform much better in terms of Static Stiffness over a wider load range. It is also found that, for small bearing eccentricity, the optimal design restriction ratio of 0.25 still results in high bearing Stiffness even if the dimensionless Stiffness of membrane is not the optimal value of 1.33. Furthermore, decreasing the ratio of the upper effective area to the lower effective area generally increases the applicable working range of the bearing. Additionally, for high loading demands, the chance for further improvement of bearing performance by employing different design parameter for each pad is examined. Finally, a design procedure for designing the membrane restrictor for an opposed-pad bearing to achieve high Static Stiffness is given
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parameters design of a membrane type restrictor with single pad hydroStatic bearing to achieve high Static Stiffness
Tribology International, 2017Co-Authors: Ta-hua Lai, Tingyu Chang, Yalu Yang, Shih-chieh LinAbstract:Abstract The analysis described in this article shows that a high Static Stiffness of the bearing is attainable as two design parameters of membrane-type restrictor are properly chosen. The first one is the dimensionless Stiffness of the membrane and the other one is the design restriction ratio of the bearing system. When the deformation-load relationship of the restrictor is compliance with the ideal trend, the Stiffness of the bearing should theoretically approach infinite in most application range. It was derived that a dimensionless membrane Stiffness of 1.33 and a design restriction ratio of 0.25 is the solution for such condition. The film thickness for the bearing will be maintained at designed levels over a loading range.
Christof Roosli - One of the best experts on this subject based on the ideXlab platform.
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effects of middle ear quasi Static Stiffness on sound transmission quantified by a novel 3 axis optical force sensor
Hearing Research, 2018Co-Authors: Ivo Dobrev, Jae Hoon Sim, Baktash Aqtashi, Alexander M Huber, Thomas Linder, Christof RoosliAbstract:Background Intra-operative quantification of the ossicle mobility could provide valuable feedback for the current status of the patient's conductive hearing. However, current methods for evaluation of middle ear mobility are mostly limited to the surgeon's subjective impression through manual palpation of the ossicles. This study investigates how middle ear transfer function is affected by stapes quasi-Static Stiffness of the ossicular chain. The Stiffness of the middle ear is induced by a) using a novel fiber-optic 3-axis force sensor to quantify the quasi-Static Stiffness of the middle ear, and b) by artificial reduction of stapes mobility due to drying of the middle ear. Methods Middle ear transfer function, defined as the ratio of the stapes footplate velocity versus the ear canal sound pressure, was measured with a single point LDV in two conditions. First, a controlled palpation force was applied at the stapes head in two in-plane (superior-inferior or posterior-anterior) directions, and at the incus lenticular process near the incudostapedial joint in the piston (lateral-medial) direction with a novel 3-axis PalpEar force sensor (Sensoptic, Losone, Switzerland), while the corresponding quasi-Static displacement of the contact point was measured via a 3-axis micrometer stage. The palpation force was applied sequentially, step-wise in the range of 0.1–20 gF (1–200 mN). Second, measurements were repeated with various stages of stapes fixation, simulated by pre-load on the stapes head or drying of the temporal bone, and with severe ossicle immobilization, simulated by gluing of the stapes footplate. Results Simulated stapes fixation (forced drying of 5–15 min) severely decreases (20–30 dB) the low frequency ( 4 kHz) response. Stapes immobilization (gluing of the footplate) severely reduces (20–40 dB) the low and mid frequency response (<4 kHz) but has lesser effect (<10 dB) at higher frequencies. Even moderate levels of palpation force (<3gF, <30 mN), regardless of direction, have negative effect (10–20 dB) on the low frequency (<2 kHz) response, but with less significant (5–10 dB) effect at higher frequencies. Force-displacement measurements around the incudostapedial joint showed quasi-Static Stiffness in the range of 200–500 N/m for normal middle ears, and 1000–2500 N/m (5–8-fold increase) after artificially (through forced drying) reducing the middle ear transfer function with 10–25 dB at 1 kHz. Conclusion Effects of the palpation force level and direction, as well as stapes fixation and immobilization have been analyzed based on the measurement of the stapes footplate motion, and controlled application of 3D force and displacement.
Yuan Kang - One of the best experts on this subject based on the ideXlab platform.
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design for Static Stiffness of hydroStatic bearings double action variable compensation of membrane type restrictors and self compensation
Industrial Lubrication and Tribology, 2014Co-Authors: Yuan Kang, Yu-hong Hung, De-xing Peng, Chorngshyan LinAbstract:Purpose – This article is the fourth part of a serial studies about constant and variable compensations of the closed-type hydroStatic plane-pad bearing, which is presented for the double-action membrane-type restrictor and self-type compensation. The paper aims to discuss these issues. Design/methodology/approach – The load capacity and Static Stiffness in thrust direction of the planar bearing is determined by the flow continuity equation which belongs to the same approaches as shown in previous parts of this serial studies. Findings – The results reveal that the appropriate range of recess pressure ratio and design parameters of bearing and restrictor for the infinite or maximum Stiffness can be obtained. Also, the influence of design parameters on negative Stiffness that should be avoided in bearing design is revealed in detail. Originality/value – The determination of design parameters of a double-action membrane-type restrictor can be yielded from finding results of this study for maximum Stiffness ...
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Design for Static Stiffness of hydroStatic bearings: double-action variable compensation of spool-type restrictors
Industrial Lubrication and Tribology, 2014Co-Authors: Yuan Kang, Ding-wen Yang, Yu-hong Hung, De-xing Peng, Shih-kang ChenAbstract:Purpose – This paper is the third part of a serial studies for constant and variable compensations of the closed-type hydroStatic thrust bearings which has face-to-face recesses couple. The Static Stiffness of closed-type hydroStatic thrust bearings can then be obtained from the differentiation of recess pressure with respect to worktable displacement. The paper aims to discuss these issues. Design/methodology/approach – In this paper, the double-action restrictors of cylindrical-spool-type and tapered-spool-type are taken into consideration for variable compensation of hydroStatic bearings. Findings – The Static Stiffness in thrust direction of hydroStatic bearing is determined by the flow continuity equations that are formulated by film flow and compensation flow for each recess, respectively. The type selection and parameter determination of the double-action spool-type restrictors can be obtained from finding results of this study for maximum Stiffness in design of hydroStatic bearings. Originality/va...
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design for Static Stiffness of hydroStatic plain bearings constant compensations
Industrial Lubrication and Tribology, 2011Co-Authors: Yuan Kang, De-xing Peng, Jianlin Lee, Huachih Huang, Chingyuan Lin, Hsinghan Lee, Chingchu HuangAbstract:Purpose – The paper aims to determine whether the type selection and parameters determination of the compensation are most important for yielding the acceptable or optimized characteristics in design of hydroStatic bearings.Design/methodology/approach – This paper utilizes the equations of flow equilibrium to determine the film thickness or displacement of worktable with respect to the recess pressure.Findings – The Stiffness due to compensation of constant‐flow pump increases monotonically as recess pressure increases. Also, the paper considers which is larger than that due to orifice compensation and capillary compensation at the same recess pressure ratio.Originality/value – The findings show that the usage range of recess pressure and compensation parameters can be selected to correspond to the smallest gradient in variations of worktable displacement or film thickness.
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design for Static Stiffness of hydroStatic bearings single action variable compensations
Industrial Lubrication and Tribology, 2011Co-Authors: Yuan Kang, Yu-hong Hung, Hsinghan Lee, Chenghsien Chen, Shunte HsiaoAbstract:Purpose – This study aims to utilize the equations of flow equilibrium to determine the variations of film thickness or worktable displacement with respect to the recess pressure for both open‐ and closed‐type hydroStatic flat bearings. The Static Stiffness can be not only presented directly by these variations but also determined by the differentiation of flow equilibrium equations.Design/methodology/approach – The single‐action variable compensations of three types including cylindrical‐spool, conical‐spool and membrane restrictors are taken into consideration in this study. Specifically, this study presents that membrane restrictor and both spool restrictors with or without preload whilst considering initial opening.Findings – Consequently, the usage range of recess pressure and optimal parameters of appropriate compensation type can be obtained from maximum Stiffness and also according to smallest gradient in variations of worktable displacement or film thickness.Originality/value – This article studi...
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Foresight in Static Stiffness of hydroStatic bearings with various compensations by film gradient versus recess pressure
Industrial Lubrication and Tribology, 2010Co-Authors: Yuan Kang, Cheng‐hsien Chen, Jian‐lin Lee, Juhn-horng Chen, Yeon-pun ChangAbstract:Purpose – The purpose of this paper is to investigate the Static Stiffness of hydroStatic bearings with three constant compensations in types of constant‐flow pump, capillary and orifice, and both single‐action and double‐action variable restrictors with cylindrical‐spool, tapered‐spool, and membrane types by film gradient and recess pressure.Design/methodology/approach – This paper utilizes the equations of flow equilibrium to determine the variations of film thickness or displacement of loading table with respect to the varying of recess pressure. For a hydroStatic bearing whose recess pressures are controlled by compensations, the Stiffness characteristics can be presented directly by these variations.Findings – The usage range of recess pressure and compensation parameters should be selected to correspond to a variation with smallest gradient.Originality/value – This paper proposes an extensive database as a critical requirement for the selection of types and parameters of the compensation as to yield...
Hugo Partsch - One of the best experts on this subject based on the ideXlab platform.
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the Static Stiffness index an important parameter to characterise compression therapy in vivo
Journal of Wound Care, 2016Co-Authors: Hugo Partsch, Giovanni Mosti, Jan Schuren, J P BenigniAbstract:The compression pressure, which corresponds to the dosage of compression therapy, has been widely neglected up to now, not only concerning scientific literature, but also in clinical practice. It is evident that compression pressures in the upright position and during walking are clinically more relevant than just the resting pressure. The Static Stiffness Index (SSI), which is the difference between standing and resting pressure, is a valuable parameter characterising the efficacy of a specific compression product to narrow/occlude the venous lumen. This is a prerequisite for reducing venous reflux and exerting a massaging effect necessary to improve the venous pumping function during movement. This article provides an overview of the recent literature on the SSI, which supports the recommendations of the International Compression Club. In addition, it aims to provide an insight on the importance of the SSI in daily practice, as an educational tool as well as in defining the properties of applied compres...
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The Static Stiffness Index: an important parameter to characterise compression therapy in vivo.
Journal of wound care, 2016Co-Authors: Hugo Partsch, Giovanni Mosti, Jan Schuren, J P BenigniAbstract:The compression pressure, which corresponds to the dosage of compression therapy, has been widely neglected up to now, not only concerning scientific literature, but also in clinical practice. It is evident that compression pressures in the upright position and during walking are clinically more relevant than just the resting pressure. The Static Stiffness Index (SSI), which is the difference between standing and resting pressure, is a valuable parameter characterising the efficacy of a specific compression product to narrow/occlude the venous lumen. This is a prerequisite for reducing venous reflux and exerting a massaging effect necessary to improve the venous pumping function during movement. This article provides an overview of the recent literature on the SSI, which supports the recommendations of the International Compression Club. In addition, it aims to provide an insight on the importance of the SSI in daily practice, as an educational tool as well as in defining the properties of applied compression therapy in clinical research.
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the Static Stiffness index a simple method to assess the elastic property of compression material in vivo
Dermatologic Surgery, 2005Co-Authors: Hugo PartschAbstract:BackgroundThe efficacy of compression therapy depends mainly on the exerted pressure and on the Stiffness of the material.ObjectiveTo propose a simple method by which pressure and Stiffness can be assessed in the individual patient.Material and MethodsUsing a pressure transducer (Kikuhime small prob
Ta-hua Lai - One of the best experts on this subject based on the ideXlab platform.
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A Simulation Study for the Design of Membrane Restrictor in an Opposed-Pad HydroStatic Bearing to Achieve High Static Stiffness
MDPI AG, 2018Co-Authors: Ta-hua Lai, Shih-chieh LinAbstract:The effects of a membrane restrictor’s design parameters on the performance of a hydroStatic opposed-pad bearing are presented in this article. Compared to the single-pad bearing, the opposed-pad bearing can perform much better in terms of Static Stiffness over a wider load range. It is also found that, for small bearing eccentricity, the optimal design restriction ratio of 0.25 still results in high bearing Stiffness even if the dimensionless Stiffness of membrane is not the optimal value of 1.33. Furthermore, decreasing the ratio of the upper effective area to the lower effective area generally increases the applicable working range of the bearing. Additionally, for high loading demands, the chance for further improvement of bearing performance by employing different design parameter for each pad is examined. Finally, a design procedure for designing the membrane restrictor for an opposed-pad bearing to achieve high Static Stiffness is given
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parameters design of a membrane type restrictor with single pad hydroStatic bearing to achieve high Static Stiffness
Tribology International, 2017Co-Authors: Ta-hua Lai, Tingyu Chang, Yalu Yang, Shih-chieh LinAbstract:Abstract The analysis described in this article shows that a high Static Stiffness of the bearing is attainable as two design parameters of membrane-type restrictor are properly chosen. The first one is the dimensionless Stiffness of the membrane and the other one is the design restriction ratio of the bearing system. When the deformation-load relationship of the restrictor is compliance with the ideal trend, the Stiffness of the bearing should theoretically approach infinite in most application range. It was derived that a dimensionless membrane Stiffness of 1.33 and a design restriction ratio of 0.25 is the solution for such condition. The film thickness for the bearing will be maintained at designed levels over a loading range.