scholarly journals Nonrigid Registration of Monomodal MRI Using Linear Viscoelastic Model

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Jian Yang ◽  
Yang Chen ◽  
Jingfan Fan ◽  
Songyuan Tang
Keyword(s):  
Fluid Model ◽  
Viscoelastic Model ◽  
Elastic Solid ◽  
Maxwell Model ◽  
Nonrigid Registration ◽  
Registration Accuracy ◽  
Maximum Displacement ◽  
Linear Viscoelastic ◽  
Synthetic Datasets ◽  
Linear Viscoelastic Model

This paper describes a method for nonrigid registration of monomodal MRI based on physical laws. The proposed method assumes that the properties of image deformations are like those of viscoelastic matter, which exhibits the properties of both an elastic solid and a viscous fluid. Therefore, the deformation fields of the deformed image are constrained by both sets of properties. After global registration, the local shape variations are assumed to have the properties of the Maxwell model of linear viscoelasticity, and the deformation fields are constrained by the corresponding partial differential equations. To speed up the registration, an adaptive force is introduced according to the maximum displacement of each iteration. Both synthetic datasets and real datasets are used to evaluate the proposed method. We compare the results of the linear viscoelastic model with those of the fluid model on the basis of both the standard and adaptive forces. The results demonstrate that the adaptive force increases in both models and that the linear viscoelastic model improves the registration accuracy.

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).

Optimization of a Viscoelastic Structure: The Seat-Belt Problem

1969 ◽  
Vol 36 (3) ◽  
pp. 565-572 ◽  
Author(s):  
W. Nachbar ◽  
J. B. Schipmo¨lder
Keyword(s):  
Seat Belt ◽  
Viscoelastic Model ◽  
Small Strain ◽  
The Body ◽  
Strain Rates ◽  
Maximum Displacement ◽  
Critical Displacement ◽  
Viscoelastic Models ◽  
Maximum Value ◽  
Linear Viscoelastic

Optimization of the parameters of elementary linear viscoelastic models is considered for the design of a lap seat belt in automobiles. The vehicle is assumed to stop abruptly on impact. The parameters are optimized to allow the speed of the vehicle before impact to have the largest permissible value consistent with constraints imposed for the safety of the user of the belt. The constraints chosen here are: (a) the maximum displacement of the body after impact is equal to or less than a prescribed critical displacement; (b) the forward speed of the body at the critical displacement does not exceed a prescribed maximum value; (c) the force exerted by the belt on the body during the motion following impact does not exceed a prescribed maximum value. It is found that the optimized Kelvin-Voigt viscoelastic model is nearly 40 percent more effective than the purely elastic material. It is nearly as effective as constant deceleration. An additional and advantageous property is proposed, moreover, for belts of viscoelastic materials. This is that the material should have a relatively low spring rate at relatively small strain rates. The optimized belts for the elementary viscoelastic models are shown to be quite stiff at low strain rates, however.

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