PHYSICAL MODELING OF DAMPING CHARACTERISTICS OF MR FLUIDS

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2704-2710
Author(s):  
JEROME SARRAZIN ◽  
JEROME CLARACQ ◽  
JEAN-PIERRE MONTFORT
Keyword(s):  
Experimental Data ◽  
Physical Modeling ◽  
Magnetic Force ◽  
Viscoelastic Behavior ◽  
Complex Shear Modulus ◽  
Mechanical Spectroscopy ◽  
Viscous Forces ◽  
Damping Characteristics ◽  
Mr Fluids ◽  
Complex Shear

The behavior of MR fluids involved in industrial devices is often modeled by analogical models which do no link the parameters with the physical properties of the fluid. From the equations of fluid mechanics, we give a physical meaning to parameters such as friction, elastic and mass coefficients used in the mentioned models. The predictions are checked with experimental data which mimic the behavior of devices such as antiseismic systems. The viscoelastic behavior of MR fluids is characterized by mechanical spectroscopy. The complex shear modulus G *(ω) contains all the information about the restoring and viscous forces. For example, the relation between elastic modulus, yield stress and magnetic force is discussed in terms of strain amplitude.

EFFECT OF VISCOELASTIC BEHAVIOR OF CELLULOSE OIL PALM FIBER (COPF) MODIFIED 60-70 ASPHALT BINDER FOR DETERIORATION FOR ROADS AND HIGHWAYS

2015 ◽  
Vol 75 (11) ◽  
Author(s):  
Md. Maniruzzaman A. Aziz ◽  
Ahmed Wsoo Hamad ◽  
Abdulmalik Musa Maleka ◽  
Fauzan Mohd Jakarni
Keyword(s):  
Shear Modulus ◽  
Oil Palm ◽  
Softening Point ◽  
Asphalt Binder ◽  
Viscoelastic Behavior ◽  
Complex Shear Modulus ◽  
Palm Fiber ◽  
Modified Asphalt ◽  
Complex Shear ◽  
Modified Asphalt Binder

This paper dealt with the viscoelastic behavior of Cellulose Oil Palm Fiber (COPF) modified 60-70 penetration grade asphalt binder for the deterioration of roads. The main objective of this study was to investigate the effect of various COPF contents on the physical and the rheological properties of penetration grade 60-70 asphalt binder. Laboratory tests performed comprised of viscosity, penetration, softening point, short & long term ageing, as well as complex shear modulus (G*).  The COPF was blended in 0.2, 0.4, 0.6, 0.8, and 1.0% by weight of asphalt binder, including 0% as control. The COPF modified asphalt binder showed an increasing viscosity and softening point with the increase of COPF content, whereas the penetration decreased as the COPF was increased for the binder. The complex shear modulus (G*), rutting factor (G*/sin δ), and fatigue factor (G*sin δ) showed significant improvement for the modified samples compared to the unmodified samples. The results indicated that the COPF modified asphalt binder had high potential to resist permanent (rutting) deformation and fatigue cracking than the unmodified sample. 

CHARACTERIZING THE EFFECT OF TEMPERATURE AND MAGNETIC FIELD STRENGTHS ON THE COMPLEX SHEAR MODULUS PROPERTIES OF MAGNETORHEOLOGICAL (MR) FLUIDS

2005 ◽  
Vol 19 (07n09) ◽  
pp. 1318-1324 ◽  
Author(s):  
W. W. CHOOI ◽  
S. O. OYADIJI
Keyword(s):  
Magnetic Field ◽  
Shear Modulus ◽  
Complex Modulus ◽  
Loss Modulus ◽  
Excitation Frequency ◽  
Effect Of Temperature ◽  
Complex Shear Modulus ◽  
Mr Fluids ◽  
Complex Shear ◽  
Frequency Coverage

When a magnetic field is applied across MR fluids, a yield stress is developed, and their rheological properties can then be categorized into two distinct regimes; pre-yield and post-yield. This paper concerns the viscoelastic behaviour of MR fluids in the pre-yield region. Oscillatory tests were carried out to determine the complex shear modulus properties of MR fluids between the temperature range of -20°C and +50°C. The test results show that the storage modulus and loss modulus increased in value as the excitation frequency was increased from 5Hz to 50Hz. The complex modulus was also found to be influenced by changes in temperature; the higher the temperature, the lower the complex modulus. This is consistent with the behaviour of viscoelastic polymers. The sets of temperature-dependent and frequency-dependent data were subsequently condensed using the method of reduced variables into master curves of complex modulus which effectively extended the frequency coverage of the data at the reference temperature.

Flexural Vibrations of an Elastic Plate With Two Symmetric Viscoelastic Coatings

1967 ◽  
Vol 34 (1) ◽  
pp. 187-194
Author(s):  
Paul Hertelendy ◽  
Werner Goldsmith
Keyword(s):  
Composite Plate ◽  
Flexural Vibration ◽  
Complex Shear Modulus ◽  
Viscous Effects ◽  
Approximate Methods ◽  
Linear Viscoelastic Material ◽  
Complex Shear ◽  
Linear Viscoelastic ◽  
Modal Behavior ◽  
Viscoelastic Coatings

The flexural-vibration characteristics of a symmetric, doubly infinite composite plate consisting of two outer layers of a linear viscoelastic material bonded to an elastic core have been examined, the viscous effects in the coating being represented by a complex shear modulus. Calculations of the dispersive and damping effects have been obtained for the lowest three modes by an extension of the exact Rayleigh-Lamb equations. Loss factors of the lowest modes have also been evaluated by two readily computed approximate methods; the results have been compared with those from the exact solution. The material constants were chosen to be representative of a high-polymer coating and an aluminum core. The modal behavior of the systems and coupling effects are discussed.

scholarly journals A sensitive dynamic viscometer for measuring the complex shear modulus in a steady shear flow using the method of orthogonal superposition

1995 ◽  
Vol 34 (6) ◽  
pp. 606-621 ◽  
Author(s):  
Jos Zeegers ◽  
Dirk van den Ende ◽  
Cor Blom ◽  
Egbert G. Altena ◽  
Gerrit J. Beukema ◽  
...  
Keyword(s):  
Shear Flow ◽  
Shear Modulus ◽  
Steady Shear ◽  
Complex Shear Modulus ◽  
Complex Shear ◽  
Steady Shear Flow ◽  
Dynamic Viscometer

MAGNETIC BODY FORCE

2005 ◽  
Vol 19 (07n09) ◽  
pp. 1205-1208 ◽  
Author(s):  
A. F. BAKUZIS ◽  
KEZHENG CHEN ◽  
WEILI LUO ◽  
HONGZHANG ZHUANG
Keyword(s):  
Experimental Data ◽  
Magnetic Fluid ◽  
Magnetic Force ◽  
Body Force ◽  
Wide Range ◽  
Magnetic Body Force ◽  
Good Agreement

We have studied magnetic force on sperical magnetic fluid samples with a wide range of concentrations by pendulum method. The results demonstrate good agreement with Kelvin body force and show that other force expressions clearly deviate from experimental data for large sussceptibility values.

Sign in / Sign up

Export Citation Format

Share Document