scholarly journals The 2S2P1D: An Excellent Linear Viscoelastic Model

2010 ◽  
Vol 1 (2) ◽  
pp. 1-7 ◽  
Author(s):  
Md. Yusoff ◽  
N. I. Monieur D. ◽  
Airey G. D.
Keyword(s):  
Viscoelastic Properties ◽  
Goodness Of Fit ◽  
Test Procedure ◽  
Viscoelastic Model ◽  
Dynamic Data ◽  
Experimental Campaign ◽  
Wide Range ◽  
2S2p1d Model ◽  
Linear Viscoelastic ◽  
Linear Viscoelastic Model

An experimental campaign has been carried out on five different unaged and five aged penetration grade bitumens to determine the properties of the 2S2P1D (combinations of two springs, two parabolic elements and one dashpot) model. The dynamic oscillatory test was conducted in order to obtain the rheological data using the dynamic shear rheometer (DSR). Earlier, the samples were aged following the Rolling Thin Film Oven Test (RTOFT) test procedure. It was found that the 2S2P1D model which consists of seven parameters simulates in an excellent way the linear viscoelastic properties of aged and unaged penetration grade bitumens over a wide range of temperatures and frequencies. The goodness of fit statistical analysis showed that the model had a good correlation and comparable to the measured dynamic data.

scholarly journals On nonlinear viscoelastic deformations: a reappraisal of Fung's quasi-linear viscoelastic model

2014 ◽  
Vol 470 (2166) ◽  
pp. 20140058 ◽  
Author(s):  
Riccardo De Pascalis ◽  
I. David Abrahams ◽  
William J. Parnell
Keyword(s):  
Integral Equation ◽  
Volterra Integral Equation ◽  
Linear Viscoelasticity ◽  
Viscoelastic Model ◽  
Discretization Scheme ◽  
Uniaxial Elongation ◽  
Nonlinear Viscoelastic ◽  
Wide Range ◽  
Linear Viscoelastic ◽  
Linear Viscoelastic Model

This paper offers a reappraisal of Fung's model for quasi-linear viscoelasticity. It is shown that a number of negative features exhibited in other works, commonly attributed to the Fung approach, are merely a consequence of the way it has been applied. The approach outlined herein is shown to yield improved behaviour and offers a straightforward scheme for solving a wide range of models. Results from the new model are contrasted with those in the literature for the case of uniaxial elongation of a bar: for an imposed stretch of an incompressible bar and for an imposed load. In the latter case, a numerical solution to a Volterra integral equation is required to obtain the results. This is achieved by a high-order discretization scheme. Finally, the stretch of a compressible viscoelastic bar is determined for two distinct materials: Horgan–Murphy and Gent.

Characterization of Multilayer Material Properties of Descending Aorta

2012 ◽  
Author(s):  
Ali Hemmasizadeh ◽  
Kurosh Darvish ◽  
Michael Autieri
Keyword(s):  
Traumatic Injury ◽  
Viscoelastic Model ◽  
Homogeneous Layer ◽  
Stent Grafts ◽  
Multilayer Material ◽  
Custom Made ◽  
Wide Range ◽  
Linear Viscoelastic ◽  
Linear Viscoelastic Model

In a wide range of biomechanical modeling of aorta from traumatic injury to stent grafts, the arterial wall has been considered as a single homogeneous layer vessel, ignoring the fact that arteries are composed of distinct anatomical layers with different mechanical characteristics. In this study, using a custom-made nanoindentation technique, changes in the mechanical properties of porcine thoracic aorta wall in the radial direction were characterized using a quasi-linear viscoelastic model. Two layers of equal thickness were mechanically distinguishable based on the radial variations in the instantaneous Young’s modulus E and reduced relaxation function G(t). The overall results showed that the outer half was stiffer and showed less relaxation than the inner half. These layers may correspond to media and adventitia in the specimens.

A non-linear viscoelastic model with structure-dependent relaxation times

1976 ◽  
Vol 1 (2) ◽  
pp. 147-157 ◽  
Author(s):  
D. Acierno ◽  
F.P. La Mantia ◽  
G. Marrucci ◽  
G. Rizzo ◽  
G. Titomanlio
Keyword(s):  
Relaxation Times ◽  
Viscoelastic Model ◽  
Non Linear ◽  
Linear Viscoelastic ◽  
Linear Viscoelastic Model

A non-linear viscoelastic model for sediments flocculated in the presence of seawater salts

2015 ◽  
Vol 482 ◽  
pp. 500-506 ◽  
Author(s):  
Christian Goñi ◽  
Ricardo I. Jeldres ◽  
Pedro G. Toledo ◽  
Anthony D. Stickland ◽  
Peter J. Scales
Keyword(s):  
Viscoelastic Model ◽  
Non Linear ◽  
Linear Viscoelastic ◽  
Linear Viscoelastic Model

scholarly journals Modelling liver tissue properties using a non-linear viscoelastic model ror surgery simulation

2002 ◽  
Vol 12 ◽  
pp. 146-153 ◽  
Author(s):  
J.-M. Schwartz ◽  
M. Dellinger ◽  
D. Rancourt ◽  
C. Moisan ◽  
D. Laurendeau
Keyword(s):  
Liver Tissue ◽  
Viscoelastic Model ◽  
Surgery Simulation ◽  
Tissue Properties ◽  
Non Linear ◽  
Linear Viscoelastic ◽  
Linear Viscoelastic Model

Estimating the ‘In-Service’ Modulus of Elasticity and Length of Polyester Mooring Lines via a Non Linear Viscoelastic Model Governed by Fractional Derivatives

2012 ◽  
Author(s):  
Georgios I. Evangelatos ◽  
Pol D. Spanos
Keyword(s):  
Modulus Of Elasticity ◽  
Field Data ◽  
Fractional Derivatives ◽  
Viscoelastic Model ◽  
Mooring Lines ◽  
Static Modulus ◽  
Proposed Model ◽  
Non Linear ◽  
Linear Viscoelastic ◽  
Linear Viscoelastic Model

In this paper a non linear viscoelastic model governed by fractional derivatives is presented for modeling the in-service behavior of polyester mooring lines. In the formulation an iterative approach utilizing the Gauss-Newton minimization algorithm in conjunction with the catenary equations used to determine the static modulus of elasticity and the effective length of polyester mooring lines corresponding to calm sea conditions. Upon establishing the accuracy of the static modulus via comparison with field data, the catenary equations and the offshore platform’s position versus time are used to identify the polyester strain under developed-sea conditions. In this manner, time histories of stress and strain for polyester ropes in service conditions are obtained. Then, a non linear viscoelastic model involving fractional derivative terms is used to capture the in service polyester line behavior. For this, the tension of the proposed model corresponding to the actual polyester strain is compared at each time step to the tension obtained from the field data. Finally, the parameters of the proposed model are derived by minimizing the error in the least-squares sense over a large number of data points using the Levenberg-Marquardt algorithm. The numerically derived force-strain relationship is found to be in reasonable agreement with supplementary field and laboratory experimental data, the field data pertain to an offshore structure moored in position using polyester mooring lines operated in the Gulf of Mexico during Hurricane Katrina (August of 2005).

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