Some recent developments in linear viscoelastic stress analysis

The use of viscosity temperature relationships to predict creep performance of road bitumens have been shown to be inadequate in particular with respect to the analysis of polymer modified binders. In this paper we explore the origins of the US Strategic Highway Research Programmebinder performance grading system and detail two examples of more recent developments towards improved creep characterisation.Starting from first principles, an equation to analyse the ratio of dissipated to stored energy during sinusoidal loading of viscoelastic bitumen was derived. The energy equation was contrasted with an empirical relationship proposed by Anderson D.A., and with a second more theoretical derivation proposed by Shenoy A.Using frequency sweep data from a conventional 40/50 pen grade bitumen and a proprietary SBS modified binder, the applicability of the energy equation was subsequently compared to the two aforementioned post-SHRP creep relations. Recommendations are made regarding the suitability of the proposed relations in ranking bitumen creep performance.

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Stress Analysis. Recent developments in numerical and experimental methods. Edited by O. C. Zienkiewicz and G. W. Holister. John Wiley, London. 1965. 469 pp. Diagrams. Tables. 95s.

Journal of the Royal Aeronautical Society ◽

10.1017/s0368393100081839 ◽

1965 ◽

Vol 69 (659) ◽

pp. 806-806

Author(s):

I. T. Cook

Keyword(s):

Stress Analysis ◽

Experimental Methods ◽

Recent Developments

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Linear Viscoelastic Stress Analysis

North-Holland Series in Applied Mathematics and Mechanics - Creep and Relaxation of Nonlinear Viscoelastic Materials ◽

10.1016/b978-0-7204-2369-3.50009-6 ◽

1976 ◽

pp. 108-130

Keyword(s):

Stress Analysis ◽

Linear Viscoelastic

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Transient Linear Viscoelastic Stress Analysis Based on the Equations of Motion in Time Integral

Transactions of the Korean Society of Mechanical Engineers A ◽

10.3795/ksme-a.2003.27.9.1579 ◽

2003 ◽

Vol 27 (9) ◽

pp. 1579-1588

Author(s):

Sung-Hee Lee ◽

Woo-Jin Sim

Keyword(s):

Stress Analysis ◽

Equations Of Motion ◽

Time Integral ◽

Linear Viscoelastic

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Solution of Viscoelastic Stress Analysis Problems Using Measured Creep or Relaxation Functions

Journal of Applied Mechanics ◽

10.1115/1.3630057 ◽

1963 ◽

Vol 30 (1) ◽

pp. 127-133 ◽

Cited By ~ 128

Author(s):

E. H. Lee ◽

T. G. Rogers

Keyword(s):

Stress Analysis ◽

Integral Equations ◽

Creep Compliance ◽

Relaxation Modulus ◽

Material Behavior ◽

Relaxation Functions ◽

Analysis Theory ◽

Linear Viscoelastic Material ◽

Linear Viscoelastic ◽

Improved Technique

Stress analysis problems for linear viscoelastic material behavior are solved on the basis of integral operator stress-strain relations. These characterize the material by relaxation modulus functions or creep compliances which are directly measurable over finite time ranges, and completely describe material behavior for stress determinations for the same duration. The stress analysis theory can lead to integral equations which are shown to be soluble with high accuracy by simple finite-difference numerical integration procedures. Examples are presented and compared with solutions obtained by other methods. A possible improved technique for relaxation modulus and creep compliance measurements is suggested, based on the method presented for numerical solution of the integral equations.

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Stress analysis for linear viscoelastic cylinders

AIAA Journal ◽

10.2514/3.5599 ◽

1970 ◽

Vol 8 (1) ◽

pp. 18-22 ◽

Cited By ~ 13

Author(s):

EDWARD C. TING

Keyword(s):

Stress Analysis ◽

Linear Viscoelastic

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Recent Developments in Stress Analysis by Diffraction Methods

Advances in X-ray Analysis ◽

10.1154/s0376030800009137 ◽

1991 ◽

Vol 35 (A) ◽

pp. 449-460

Author(s):

V. Hauk

Keyword(s):

Residual Stresses ◽

Stress Analysis ◽

The Third ◽

Recent Developments

AbstractStarting in Germany (Garmisch Partenkirchen, 1986) we had the 1st ICRS (Int. Conf. on Residual Stresses). The second was held in France (Nancy, 1988), the third in Japan (Tokushima 1991). In all areas, the diffraction measurements furnish exceptional contributions, and in many cases they are the only methods capable of solving problems. Because of the importance of the diffraction methods, the literature on residualstress analysis (RSA) has enlarged in the last years, Figure 1.

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Microstructural behavior of magnetorheological elastomer undergoing durability evaluation by stress relaxation

Scientific Reports ◽

10.1038/s41598-021-90484-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Mohd Aidy Faizal Johari ◽

Saiful Amri Mazlan ◽

Mohamed Mahmoud Nasef ◽

U. Ubaidillah ◽

Nur Azmah Nordin ◽

...

Keyword(s):

Stress Relaxation ◽

Microphase Separation ◽

Shear Bands ◽

Theoretical Research ◽

Test Duration ◽

Magnetorheological Elastomer ◽

Atomic Force ◽

Recent Developments ◽

Linear Viscoelastic ◽

Molecular Deformation

AbstractThe widespread use of magnetorheological elastomer (MRE) materials in various applications has yet to be limited due to the fact that there are substantial deficiencies in current experimental and theoretical research on its microstructural durability behavior. In this study, MRE composed of silicon rubber (SR) and 70 wt% of micron-sized carbonyl iron particles (CIP) was prepared and subjected to stress relaxation evaluation by torsional shear load. The microstructure and particle distribution of the obtained MRE was evaluated by a field emission scanning electron microscopy (FESEM). The influence of constant low strain at 0.01% is the continuing concern within the linear viscoelastic (LVE) region of MRE. Stress relaxation plays a significant role in the life cycle of MRE and revealed that storage modulus was reduced by 8.7%, normal force has weakened by 27%, and stress performance was reduced by 6.88% along approximately 84,000 s test duration time. This time scale was the longest ever reported being undertaken in the MRE stress relaxation study. Novel micro-mechanisms that responsible for the depleted performance of MRE was obtained by microstructurally observation using FESEM and in-phase mode of atomic force microscope (AFM). Attempts have been made to correlate strain localization produced by stress relaxation, with molecular deformation in MRE amorphous matrix. Exceptional attention was focused on the development of molecular slippage, disentanglement, microplasticity, microphase separation, and shear bands. The relation between these microstructural phenomena and the viscoelastic properties of MRE was diffusely defined and discussed. The presented MRE is homogeneous with uniform distribution of CIP. The most significant recent developments of systematic correlation between the effects of microstructural deformation and durability performance of MRE under stress relaxation has been observed and evaluated.

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