scholarly journals Influence of cheese ripening on the viscoelastic behaviour of edam cheese

2013 ◽  
Vol 19 (No. 1) ◽  
pp. 1-7 ◽  
Author(s):  
J. Buchar ◽  
I. Kubiš ◽  
S. Gajdůšek ◽  
I. Křivánek
Keyword(s):  
Viscoelastic Properties ◽  
Rheological Model ◽  
Deformation Behaviour ◽  
Viscoelastic Body ◽  
Original Method ◽  
Cheese Ripening ◽  
Linear Viscoelastic ◽  
Standard Linear Solid ◽  
Standard Linear ◽  
Pressure Bar

The paper deals with the study of the effect of cheese ripening on parameters of a rheological model of cheese mechanical behaviour. The Edam cheese has been tested by the method of the Hopkinson Split Pressure Bar. The original method of the evaluation of viscoelastic properties has been used. The rheological model of the three element linear viscoelastic body, so called “standard linear solid” has been used. This model successfully describes the experimentally observed deformation behaviour of cheese specimens. The effect of the time of cheese ripening on the parameters of the rheological model has been demonstrated.

Viscoelastic Properties of Phagocytes in Arteriosclerotic Origin

2014 ◽  
Vol 540 ◽  
pp. 321-325
Author(s):  
Wei Zeng ◽  
Yan Rong Shi ◽  
Xiao Yan Deng
Keyword(s):  
Experimental Data ◽  
Viscoelastic Properties ◽  
Important Implication ◽  
Research Field ◽  
Solid Model ◽  
Initial Stage ◽  
Standard Linear Solid Model ◽  
Aspiration Technique ◽  
Standard Linear Solid ◽  
Standard Linear

A micropipette aspiration technique was adopted to investigate the viscoelastic properties of phagocytes of arteriosclerotic origin. A standard linear solid model was employed to fit the experimental data and three viscoelastic coefficients were used to compare the mechanical properties of the phagocytes in different phases during arteriosclerostic development. The experimental results indicated that prior to the formation of arteriosclerosis, the mobility and deformability of the marcopahges matured from monocytes decreased, and their rigidity increased. At the initial stage of arteriosclerosis formation, the mobility and deformability of the foam-cells further decreased. This finding may have important implication in the research field of arteriosclerosis.

scholarly journals Viscoelastic Characterization of Long-Eared Owl Flight Feather Shaft and the Damping Ability Analysis

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Jia-li Gao ◽  
Jin-kui Chu ◽  
Le Guan ◽  
Hai-xin Shang ◽  
Zhen-kun Lei
Keyword(s):  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Golden Eagle ◽  
Flight Feather ◽  
Column Material ◽  
Significant Difference ◽  
Single Column ◽  
Linear Viscoelastic ◽  
Standard Linear Solid ◽  
Standard Linear

Flight feather shaft of long-eared owl is characterized by a three-parameter model for linear viscoelastic solids to reveal its damping ability. Uniaxial tensile tests of the long-eared owl, pigeon, and golden eagle flight feather shaft specimens were carried out based on Instron 3345 single column material testing system, respectively, and viscoelastic response of their stress and strain was described by the standard linear solid model. Parameter fitting result obtained from the tensile tests shows that there is no significant difference in instantaneous elastic modulus for the three birds’ feather shafts, but the owl shaft has the highest viscosity, implying more obvious viscoelastic performance. Dynamic mechanical property was characterized based on the tensile testing results. Loss factor (tanδ) of the owl flight feather shaft was calculated to be 1.609 ± 0.238, far greater than those of the pigeon (0.896 ± 0.082) and golden eagle (1.087 ± 0.074). It is concluded that the long-eared owl flight feather has more outstanding damping ability compared to the pigeon and golden eagle flight feather shaft. Consequently, the long-eared owl flight feathers can dissipate the vibration energy more effectively during the flying process based on the principle of damping mechanism, for the purpose of vibration attenuation and structure radiated noise reduction.

The Fractional derivative rheological model and the linear viscoelastic behavior of hydrocolloids

2012 ◽  
Vol 33 (1) ◽  
pp. 141-151 ◽  
Author(s):  
Magdalena Orczykowska ◽  
Marek Dziubiński
Keyword(s):  
Fractional Derivative ◽  
Viscoelastic Properties ◽  
Rheological Model ◽  
Xanthan Gum ◽  
Viscoelastic Behavior ◽  
Rheological Parameters ◽  
Rice Starch ◽  
Linear Viscoelastic Behavior ◽  
Linear Viscoelastic ◽  
The Impact

The Fractional derivative rheological model and the linear viscoelastic behavior of hydrocolloids This study was aimed at evaluating the possibility to use the Friedrich-Braun fractional derivative rheological model to assess the viscoelastic properties of xanthan gum with rice starch and sweet potato starch. The Friedrich-Braun fractional derivative rheological model allows to describe viscoelastic properties comprehensively, starting from the behaviour characteristic of purely viscous fluids to the behaviour corresponding to elastic solids. The Friedrich-Braun fractional derivative rheological model has one more virtue which distinguishes it from other models, it allows to determine the relationship between stress and strain and the impact of each of them on viscoelastic properties on the tested material. An analysis of the data described using the Friedrich-Braun fractional derivative rheological model allows to state that all the tested mixtures of starch with xanthan gum form macromolecular gels exhibiting behaviour typical of viscoelastic quasi-solid bodies. The Friedrich-Braun fractional derivative rheological model and 8 rheological parameters of this model allow to determine changes in the structure of the examined starch - xanthan gum mixtures. Similarly important is the possibility to find out the trend and changes going on in this structure as well as their causes.

An efficient seismic modeling in viscoelastic isotropic media

Geophysics ◽  
2015 ◽  
Vol 80 (1) ◽  
pp. T63-T81 ◽  
Author(s):  
Renhu Yang ◽  
Weijian Mao ◽  
Xu Chang
Keyword(s):  
Seismic Waves ◽  
Linear Equations ◽  
Viscoelastic Body ◽  
Elastic Stiffness ◽  
Momentum Conservation ◽  
Stiffness Matrices ◽  
Isotropic Media ◽  
Linear Viscoelastic ◽  
Standard Linear ◽  
Viscoelastic Modeling

Energy is absorbed and attenuated when seismic waves propagate in real earth media. Hence, the viscoelastic medium needs to be considered. There are many ways to construct the viscoelastic body, in which the generalized standard linear viscoelastic body is the most representative one. For viscoelastic wave propagation and imaging, it is very important to obtain a compact and efficient viscoelastic equation. Because of this, we derived a set of simplified viscoelastic equations in isotropic media on the basis of the standard linear solid body and the constitutive relation for a linear viscoelastic isotropic solid. The simplified equations were composed of the linear equations of momentum conservation, the stress-strain relations, and the memory variable equations. During the derivation of the equations, the Lamé differentiation matrix, which has a similar form to the stiffness matrix and indicates the relations between viscoelastic and elastic stiffness matrices, was introduced to simplify the memory variable equations. Analogous to the elastic equations, the simplified equations have symmetrically compact forms and are very useful for efficient viscoelastic modeling, migration, and inversion. Applied to a 2D simple model and the 2D SEG/EAGE salt model, the results show that our simplified equations are more efficient in computation than Carcione’s equations.

Modeling of Viscoelastic Solid Polymers Using a Boundary Element Formulation with Considering a Body Load

2012 ◽  
Vol 463-464 ◽  
pp. 499-504 ◽  
Author(s):  
Hosein Ashrafi ◽  
M.R. Bahadori ◽  
M. Shariyat
Keyword(s):  
Boundary Element ◽  
Body Force ◽  
Element Formulation ◽  
Viscoelastic Solid ◽  
Engineering Structures ◽  
Solid Polymers ◽  
Linear Viscoelastic ◽  
Standard Linear Solid ◽  
Body Load ◽  
Standard Linear

In this work, a boundary element formulation for 2D linear viscoelastic solid polymers subjected to body force of gravity has been presented. Structural analysis of solid polymers is one of the most important subjects in advanced engineering structures. From basic assumptions of the viscoelastic constitutive equations and the weighted residual techniques, a simple but effective boundary element formulation is implemented for standard linear solid (SLS) model. The SLS model provides an approximate representation of observed behavior of a real advanced polymer in its viscoelastic range. This approach avoids the use of relaxation functions and mathematical transformations, and it is able to solve quasistatic viscoelastic problems with any load time-dependence and boundary conditions. Problem of pressurization of thick-walled viscoelastic tanks made of PMMA polymer, which subjected to a body force, is completely analyzed.

Linear viscoelasticity

2020 ◽  
pp. 549-608
Author(s):  
Lallit Anand ◽  
Sanjay Govindjee
Keyword(s):  
Time Integration ◽  
Integral Form ◽  
Essential Elements ◽  
Kernel Functions ◽  
Three Dimensions ◽  
Storage And Loss Moduli ◽  
Linear Viscoelastic Material ◽  
Linear Viscoelastic ◽  
Standard Linear Solid ◽  
Standard Linear

This chapter introduces the essential elements of linear viscoelastic material behaviour and modeling in one- and three-dimensions. Both relaxation and creep phenomena are introduced and modeled using Boltzmann’s superposition integral. Various common kernel functions are introduced, as is the standard and generalized standard linear model in differential and integral form. The correspondence principle is discussed for the solution of practical problems and to connect relaxation and creep formulations. Storage and loss moduli for oscillatory loadings are discussed, as are loss tangents and dissipation. For the generalized standard linear solid its time integration via the Herrmann-Peterson recursion relation is discussed. Effects of temperature are discussed, and the concept of time-temperature equivalence is introduced.

scholarly journals Creep in oak material from the Vasa ship: verification of linear viscoelasticity and identification of stress thresholds

2020 ◽  
Vol 78 (6) ◽  
pp. 1095-1103
Author(s):  
R. Afshar ◽  
M. Cheylan ◽  
G. Almkvist ◽  
A. Ahlgren ◽  
E. K. Gamstedt
Keyword(s):  
Rheological Parameters ◽  
Stress Strain ◽  
Compressive Stresses ◽  
Linear Viscoelastic ◽  
Standard Linear Solid ◽  
Standard Linear ◽  
Linear Viscoelastic Behaviour ◽  
Creep Deformations ◽  
High Degree ◽  
Wooden Structures

Abstract Creep deformation is a general problem for large wooden structures, and in particular for shipwrecks in museums. In this study, experimental creep data on the wooden cubic samples from the Vasa ship have been analysed to confirm the linearity of the viscoelastic response in the directions where creep was detectable (T and R directions). Isochronous stress–strain curves were derived for relevant uniaxial compressive stresses within reasonable time spans. These curves and the associated creep compliance values justify that it is reasonable to assume a linear viscoelastic behaviour within the tested ranges, given the high degree of general variability. Furthermore, the creep curves were fitted with a one-dimensional standard linear solid model, and although the rheological parameters show a fair amount of scatter, they are candidates as input parameters in a numerical model to predict creep deformations. The isochronous stress–strain relationships were used to define a creep threshold stress below which only negligible creep is expected. These thresholds ranges were 0.3–0.5 MPa in the R direction and 0.05–0.2 MPa in the T direction.

A Comparison of the Dynamic Transient Anti-Plane Shear Crack Energy Release Rate for Standard Linear Solid and Power-Law-Type Viscoelastic Materials

1991 ◽  
Vol 113 (4) ◽  
pp. 222-229 ◽  
Author(s):  
J. M. Herrmann ◽  
J. R. Walton
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Power Law ◽  
Release Rate ◽  
Shear Crack ◽  
Viscoelastic Body ◽  
Laplace Transforms ◽  
Failure Zone ◽  
Standard Linear Solid ◽  
Standard Linear

The problem of a semi-infinite mode III crack that suddenly begins to propagate at a constant speed is considered for a general linear viscoelastic body. It is shown that the results of an earlier paper for the Laplace transforms of the stress and displacement with the Laplace transform variable s being real and positive are valid, with minor modification, for complex values of s such that Re(s)>0. Therefore, these Laplace transforms can be inverted by means of a Bromwich path integral. Under the assumption that a Barenblatt-type failure zone exists at the crack tip, the energy release rate (ERR) and the work done in the failure zone (WFZ) are calculated through numerical inversion of Laplace transforms. The ERR and WFZ for the standard linear solid and power law material models are contrasted and also compared with the elastic and quasi-static results. The graphs and table illustrate considerable differences in the ERR and WFZ for these different models. These differences may be important to predictions of stable versus unstable crack speeds based upon a critical ERR fracture criterion.

scholarly journals Dynamic force microscopy simulator (dForce): A tool for planning and understanding tapping and bimodal AFM experiments

2015 ◽  
Vol 6 ◽  
pp. 369-379 ◽  
Author(s):  
Horacio V Guzman ◽  
Pablo D Garcia ◽  
Ricardo Garcia
Keyword(s):  
Viscoelastic Model ◽  
Surface Force ◽  
Dissipated Energy ◽  
Dynamic Force ◽  
Force Microscopy ◽  
Linear Viscoelastic ◽  
Standard Linear Solid ◽  
Standard Linear ◽  
Optimal Accuracy ◽  
The One

We present a simulation environment, dForce, which can be used for a better understanding of dynamic force microscopy experiments. The simulator presents the cantilever–tip dynamics for two dynamic AFM methods, tapping mode AFM and bimodal AFM. It can be applied for a wide variety of experimental situations in air or liquid. The code provides all the variables and parameters relevant in those modes, for example, the instantaneous deflection and tip–surface force, velocity, virial, dissipated energy, sample deformation and peak force as a function of time or distance. The simulator includes a variety of interactions and contact mechanics models to describe AFM experiments including: van der Waals, Hertz, DMT, JKR, bottom effect cone correction, linear viscoelastic forces or the standard linear solid viscoelastic model. We have compared two numerical integration methods to select the one that offers optimal accuracy and speed. The graphical user interface has been designed to facilitate the navigation of non-experts in simulations. Finally, the accuracy of dForce has been tested against numerical simulations performed during the last 18 years.

Sign in / Sign up

Export Citation Format

Share Document