Squeeze Film Bearing Characteristics for Synovial Joint Applications

2019 ◽  
pp. 55-72
Author(s):  
T. V. V. L. N. Rao ◽  
Ahmad Majdi Abdul Rani ◽  
Geetha Manivasagam
Keyword(s):  
Squeeze Film ◽  
Synovial Joint

Measurement of Lubricating Film Thickness in Low Elastic Modulus Lined Bearings, with Particular Reference to Models of Cushion Form Bearings for Total Joint Replacements: Part 2: Squeeze-Film Motion

1994 ◽  
Vol 208 (3) ◽  
pp. 213-217 ◽  
Author(s):  
Z M Jin ◽  
G McClure ◽  
D Dowson ◽  
J Fisher ◽  
B Jobbins
Keyword(s):  
Film Thickness ◽  
Contact Region ◽  
Thick Layer ◽  
Squeeze Film ◽  
Synovial Joint ◽  
Joint Replacements ◽  
Total Joint Replacements ◽  
Lubricating Film ◽  
Low Elastic Modulus ◽  
Theoretical Predictions

An optical interferometry technique has been successfully used to study the lubricant film thickness in a compliant layered bearing model for total joint replacements under squeeze-film motion. Experiments have been carried out for both thin and thick layers of compliant bearing material. It has been demonstrated that the film thickness patterns depend significantly upon the layer thickness if other parameters are kept constant. For the thin layer, the film thickness in the contact region was found to be essentially uniform and quite good agreement was found with the theoretical predictions based upon a simplified analysis due to Dowson et al. (13) and Higginson (14). However, for the thick layer, a central dimple or pocket was formed and a relatively large difference was found between the experimentally determined central film thickness and the simple parallel circular disc theoretical predictions. The practical implications of the present results are discussed in relation to the lubrication mechanism in the natural synovial joint and its replacement.

scholarly journals Squeeze Film Lubrication between Rough Poroelastic Rectangular Plates with Micropolar Fluid: A Special Reference to the Study of Synovial Joint Lubrication

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
N. B. Naduvinamani ◽  
G. K. Savitramma
Keyword(s):  
Surface Roughness ◽  
Film Thickness ◽  
Micropolar Fluid ◽  
Stochastic Theory ◽  
Squeeze Film ◽  
Rectangular Plates ◽  
Synovial Joint ◽  
Synovial Joints ◽  
Joint Lubrication ◽  
Load Carrying

The effects of surface roughness and poroelasticity on the micropolar squeeze film behavior between rectangular plates in general and that of synovial joints in particular are presented in this paper. The modified Reynolds equation, which incorporates the randomized surface roughness structure as well as elastic nature of articular cartilage with micropolar fluid as lubricant, is derived. The load-carrying capacity and time of approach as functions of film thickness during normal articulation of joints are obtained by using Christensen stochastic theory for rough surfaces with the assumption that the roughness asperity heights are to be small compared to the film thickness. It is observed that the effect of surface roughness has considerable effects on lubrication mechanism of synovial joints.

Response of Viscoelastic Fluids in Dynamically Loaded Bearings

1968 ◽  
Vol 90 (3) ◽  
pp. 555-559 ◽  
Author(s):  
R. I. Tanner
Keyword(s):  
Journal Bearing ◽  
Variable Viscosity ◽  
Relaxation Spectrum ◽  
Squeeze Film ◽  
Relaxation Processes ◽  
Synovial Joint ◽  
Joint Lubrication ◽  
Dynamically Loaded ◽  
Steady Shearing ◽  
Almost All

The dynamic response of polymer fluids to small sinusoidal shearing motions may be characterized by their relaxation spectra. Recent experiments show that great changes can be induced in the relaxation spectrum by steady shearing of the sample. This is the case of most relevance to bearing studies in, for example, a dynamically loaded journal bearing. It is shown that almost all relaxation processes longer than a small multiple of the (shear rate)−1 are removed by steady shearing. This result implies that in a bearing undergoing dynamic loading with Fourier components which are low harmonics of the shaft speed a polymer fluid is expected to behave very like a quasi-Newtonian fluid with variable viscosity. The action of a sheared squeeze film is also considered and the implications for synovial joint lubrication are briefly mentioned.

Ball bearing turbocharger vibration management: application on high speed balancer

2020 ◽  
Vol 21 (6) ◽  
pp. 619
Author(s):  
Kostandin Gjika ◽  
Antoine Costeux ◽  
Gerry LaRue ◽  
John Wilson
Keyword(s):  
Dynamic Behavior ◽  
High Speed ◽  
Internal Combustion Engines ◽  
Ball Bearing ◽  
Squeeze Film ◽  
Design And Technology ◽  
Squeeze Film Damper ◽  
Damping Coefficients ◽  
Bearing Loads ◽  
Stiffness And Damping

Today's modern internal combustion engines are increasingly focused on downsizing, high fuel efficiency and low emissions, which requires appropriate design and technology of turbocharger bearing systems. Automotive turbochargers operate faster and with strong engine excitation; vibration management is becoming a challenge and manufacturers are increasingly focusing on the design of low vibration and high-performance balancing technology. This paper discusses the synchronous vibration management of the ball bearing cartridge turbocharger on high-speed balancer and it is a continuation of papers [1–3]. In a first step, the synchronous rotordynamics behavior is identified. A prediction code is developed to calculate the static and dynamic performance of “ball bearing cartridge-squeeze film damper”. The dynamic behavior of balls is modeled by a spring with stiffness calculated from Tedric Harris formulas and the damping is considered null. The squeeze film damper model is derived from the Osborne Reynolds equation for incompressible and synchronous fluid loading; the stiffness and damping coefficients are calculated assuming that the bearing is infinitely short, and the oil film pressure is modeled as a cavitated π film model. The stiffness and damping coefficients are integrated on a rotordynamics code and the bearing loads are calculated by converging with the bearing eccentricity ratio. In a second step, a finite element structural dynamics model is built for the system “turbocharger housing-high speed balancer fixture” and validated by experimental frequency response functions. In the last step, the rotating dynamic bearing loads on the squeeze film damper are coupled with transfer functions and the vibration on the housings is predicted. The vibration response under single and multi-plane unbalances correlates very well with test data from turbocharger unbalance masters. The prediction model allows a thorough understanding of ball bearing turbocharger vibration on a high speed balancer, thus optimizing the dynamic behavior of the “turbocharger-high speed balancer” structural system for better rotordynamics performance identification and selection of the appropriate balancing process at the development stage of the turbocharger.

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