Oscillating circular squeeze films considering the combined effects of fluid inertial forces and non-Newtonian couple stresses

2008 ◽  
Vol 222 (7) ◽  
pp. 975-983 ◽  
Author(s):  
J-R Lin
Keyword(s):  
Inertial Forces ◽  
Combined Effects ◽  
Couple Stresses

Effects of the Electromagnetic Forces on Vibrational Behavior of the Laminated Mechanical Structure of Stator Cores

1995 ◽  
Author(s):  
Cuneyt Ozturk
Keyword(s):  
Material Properties ◽  
Significant Contribution ◽  
Experimental Methods ◽  
Inertial Forces ◽  
Combined Effects ◽  
Electric Motors ◽  
Stator Core ◽  
Electromagnetic Forces ◽  
Mechanical Structure ◽  
Magnetostrictive Deformation

Abstract Stator laminations can have mutual excitation sources depending to the inertial forces that can excite the mechanical resonances and radial components of the electromagnetic forces that vary with the magnetic flux changes and the magnetostrictive forces. Magnetostrictive forces can appear depending to the material properties of the plates and have mechanical and magnetic causes Mechanical properties of the lamination plates can be determined both in numerical and experimental methods. Magnetostrictive effects of the laminations have significant contribution to the audible noise of electric motors. The combined effects of radial components of electromagnetic forces and magnetostrictive deformation can cause further amplification problems of noise. This study investigates the effects of magnetostrictive forces on the laminated mechanical structure of stator core by referring to the changes of the plate materials depending to applicable heat treatments, magnetic properties and silicon alloying that were all considered as factors to modify the effects of magnetostriction.

Combined effects of piezo – viscous coupled stress lubricant and rotational inertia upon squeeze film performance of rough circular discs

2015 ◽  
Vol 67 (6) ◽  
pp. 564-571 ◽  
Author(s):  
M. Daliri ◽  
D. Jalali-Vahid
Keyword(s):  
Surface Roughness ◽  
Couple Stress ◽  
Squeeze Film ◽  
Rotational Inertia ◽  
Combined Effects ◽  
Film Performance ◽  
Content Type ◽  
Couple Stresses ◽  
Pressure Dependency ◽  
Film Characteristics

Purpose – The purpose of this paper is to investigate squeezing and rotating motions between two rough parallel circular discs lubricated by piezo – viscous couple stress lubricant with pressure-dependent viscosity variation. Design/methodology/approach – Based upon the Stokes couple stress theory, Barus viscosity-pressure dependency relation and Christensen rough surfaces model, squeeze film characteristics between two rough parallel circular discs are obtained. Findings – According to the results, it is found that, the combined effects of couple stresses and viscosity-pressure dependency increases squeeze film performance with respect to the classical Newtonian iso-viscous (constant viscosity) lubricant. However, increasing the rotational inertia parameter reduces squeeze film characteristics. On the other hand, depending on the structure of surface roughness, the squeeze film characteristics can be increased or decreased. Furthermore, results show that the surface roughness with circular pattern increases squeeze film characteristics, while the surface roughness with radial pattern will decrease it. Originality/value – This paper is relatively original and describes the squeeze film characteristics between two parallel circular discs with viscosity-pressure dependency, rotational inertia, couple stresses and surface roughness effects.

Effects of couple stresses and convective inertia forces in parallel circular squeeze‐film plates

2004 ◽  
Vol 56 (6) ◽  
pp. 318-323 ◽  
Author(s):  
Jaw‐Ren Lin ◽  
Rong‐Fang Lu ◽  
Won‐Hsion Liao ◽  
Chia‐Chuan Kuo
Keyword(s):  
Couple Stress ◽  
Numerical Solutions ◽  
Continuum Theory ◽  
Momentum Equation ◽  
Mean Value ◽  
Squeeze Film ◽  
Combined Effects ◽  
Fluid Inertia ◽  
Couple Stresses ◽  
Inertia Forces

A theoretical study of the combined effects of non‐Newtonian couple stresses and fluid inertia forces on the squeeze‐film behaviors for parallel circular plates is presented in this paper. Based upon the micro‐continuum theory, the Stokes constitutive equations are used to account for the couple stress effects resulting from the lubricant blended with various additives. The convective inertia forces included in the momentum equation are approximated by the mean value averaged across the fluid film thickness. Numerical solutions for the squeezing film characteristics are presented for various values of couple stress parameter and Reynolds number. Comparing with the classical Newtonian non‐inertia flow, the combined effects of couple stresses and convective inertia forces result in a larger load‐carrying capacity and therefore, increase the response time of the squeezing film plates.

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