scholarly journals Rheological measurements of the viscoelastic properties of snow

2001 ◽  
Vol 32 ◽  
pp. 44-50 ◽  
Author(s):  
Christian Camponovo ◽  
Jürg Schweizer
Keyword(s):  
Viscoelastic Properties ◽  
Deformation Process ◽  
Large Strain ◽  
Measuring Method ◽  
Shear Loading ◽  
Small Samples ◽  
Rheological Parameters ◽  
Viscoelastic Deformation ◽  
Dependent Part ◽  
Applied Torque

AbstractIn order to determine the viscoelastic properties of snow, torsional shear measurements were performed in a cold laboratory with a stress-controlled rheometer. Small samples (60 mm in diameter and about 7 mm thick of natural snow collected from the nearby study plot were loaded in simple shear with monotonically increasing stress (stress ramp) and with sinusoidally varying stress (oscillation). The dynamic measuring method allows the deformation process to be separated into a time-independent part (elastic) and a time-dependent part (viscous). The applied torque is sufficiently small to prevent destructive deformation, generally permitting the true viscoelastic properties of a sample to be obtained over a large range of frequency and temperature. The limit strain for linear viscoelastic deformation was found to be very small (0.5−5 × 10−4). Experiments performed beyond the linear range imply important textural changes (damage, breaking of bonds). The large strain reached during stress-ramp experiments showed that the ongoing damage process must be balanced by a healing (sintering) process. The usefulness of a rheometer was proven. It is a precise method for measuring with high reproducibility the rheological parameters of snow, and data gained with it improve our understanding of the deformation process under shear loading.

Influence of Compressive Torsion Processing Temperature on Microstructure Refinement and Property of Aluminum Alloy

2007 ◽  
Vol 26-28 ◽  
pp. 133-136 ◽  
Author(s):  
Shotaro Tahara ◽  
Yuji Kume ◽  
Makoto Kobashi ◽  
Naoyuki Kanetake
Keyword(s):  
Plastic Deformation ◽  
Deformation Process ◽  
Large Strain ◽  
Tensile Elongation ◽  
Total Elongation ◽  
Work Piece ◽  
Processing Temperature ◽  
Microstructure Refinement ◽  
Plastic Deformation Process ◽  
Eutectic Si

A compressive torsion processing (CTP) was applied to hypereutectic Al-Si alloy in order to raise ductility and formability by microstructure refinement of the alloy. The CTP is a unique severe plastic deformation process and it can easily apply large strain to a work piece without change in shape. In the present work, influence of compressive torsion processing temperature on microstructure refinement and tensile property of hypereutectic Al-Si alloy is dealt with. When the CTP was applied on the Al-Si alloy, primary and eutectic Si particles were refined more effectively at lower processing temperature. Total tensile elongation of CTPed alloy was four times as large as that of non CTPed one. Distribution of the total elongation was quite uniform in the whole CTPed specimen.

A Numerical Model of Lead Material and Its Applicability to Simulation of Isolation Devices

2003 ◽  
Author(s):  
Akihiro Matsuda
Keyword(s):  
Mechanical Properties ◽  
Numerical Model ◽  
Large Strain ◽  
Tensile Loading ◽  
Cyclic Stress ◽  
Shear Loading ◽  
Test Results ◽  
Loading Test ◽  
Initial Yield Stress ◽  
Damping Material

This paper proposes a new numerical model of lead material to predict mechanical properties of isolation and vibration control devices using lead as damping material. Shear and tensile loading tests of lead were carried out to make the numerical model. Shear loading test specimen were constructed from a circumferential lead part welded at the top and bottom to steel flanges. Cyclic stress-strain relations in large strain region were obtained from shear loading test results. The elastic constants and the initial yield stress were given from tensile loading test results. Therefore a numerical model was made using both shear loading and tensile loading test results. Mechanical properties of lead dampers and isolated rubber bearings were simulated using the proposed numerical model via finite element method to show applicability of the model.

Experimental Study of Bimaterial Shear Strength and Strain Concentrations by Iosipescu Based Test Using Digital Image Correlation System

2012 ◽  
Vol 188 ◽  
pp. 226-231
Author(s):  
Tomasz Sadowski ◽  
Marcin Kneć
Keyword(s):  
Shear Strength ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Deformation Process ◽  
Adhesive Bonding ◽  
Shear Loading ◽  
Image Correlation ◽  
Strain Gauges ◽  
Final Failure ◽  
Analog Output

Adhesive bonding of two different materials appears in many modern engineering applications, e.g.: airplanes, boats, cars etc. In many practical problems the adhesive bonding is subjected to shear loading. Therefore this is important to investigate the whole deformation process of the considered type of joints under monotonic loading, to get information about the shear strength and strain concentrations. Such concentrations lead to microdefects initiation and their further coalescence to create a main crack. The unstable crack propagation leads to final failure of the adhesive joint. The Digital Image Correlation (DIC) System - ARAMIS allows for constant monitoring of the deformation state up to the final failure. The tests were performed for bi-material specimens made of adhesively bonded PMMA and aluminum strips (Fig.1) and for pure PMMA and pure aluminum specimens. Additionally, two strain gauges on each homogeneous specimen and four on the bimaterial ones are used for strains estimations. The four point bending Iosipescu tests were performed using MTS machine with constant speed. In the first method (DIC) the ARAMIS system recorded a displacement distribution in samples with frequency 1Hz. In the second method the strains were recorded by the strain gauges - using analog output channels of the HOTTINGER data Acquisition System - MGCPlus, the current value of the load using analog output channel of the MTS machine was recorded too. The load-displacement curves were obtained for the whole deformation process and the shear strength of the joints was estimated. The energy absorption of the joints was calculated.

Study on Effect of Viscoelastic Properties on Surface Roughness Uniformity in Abrasive Flow Machining for Plate Surface

2016 ◽  
Vol 1136 ◽  
pp. 131-134 ◽  
Author(s):  
Xuan Ping Wang ◽  
You Zhi Fu ◽  
Hang Gao
Keyword(s):  
Viscoelastic Properties ◽  
Material Removal ◽  
Flow Direction ◽  
Dominant Role ◽  
Machining Process ◽  
Rheological Parameters ◽  
Process Conditions ◽  
Abrasive Flow Machining ◽  
Surface Polishing ◽  
Viscoelastic Constitutive Model

Abrasive flow machining is a suitable technique for surface polishing due to its rheological characteristics, however, it's difficult to achieve uniform roughness for polished surfaces as the material removal mechanism is still ambiguous. In this paper the viscoelastic properties of abrasive flow media are incorporated to explore the phenomena of inconsistent material removal in the AFM polishing process, where the material removal near the edges is obviously higher than that in the middle along the flow direction. The rheological parameters of the viscoelastic constitutive model adopted are varied to study the polishing effectiveness under different process conditions. The results of numerical analysis reveal that there exist distinct differences of viscoelastic stress fields between the edges and the middle regions, which leads to the material removal near the edges is higher than that in the middle. It could be concluded that the viscoelastic properties of abrasive media play the dominant role for the inconsistent material removal in abrasive flow machining process.

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.

Mechanical behaviour of magnetic Silly Putty: Viscoelastic and magnetorheological properties

2015 ◽  
Vol 28 (8) ◽  
pp. 953-960 ◽  
Author(s):  
Nicola Golinelli ◽  
Andrea Spaggiari ◽  
Eugenio Dragoni
Keyword(s):  
Magnetic Field ◽  
Viscoelastic Properties ◽  
Volume Fraction ◽  
Strong Dependence ◽  
Elastic Solid ◽  
Shear Loading ◽  
System Response ◽  
Dynamic Shear ◽  
Static Compression ◽  
Long Time

In this work the mechanical and viscoelastic properties of magnetic Silly Putty are investigated. Silly Putty is a non-Newtonian material whose response depends on the rate at which it is deformed. For a rapid deformation, it behaves as an elastic solid, while over a relatively long time scale, the polymer molecules can be untangled and it flows as a fluid. The purpose of this article is to study the behaviour of this material firstly under a quasi-static compression and shear loading, and secondly under dynamic shear loading. The Silly Putty under study has a volume fraction of ferromagnetic particles. Hence, both quasi-static and dynamic stress are coupled with several strengths of magnetic field in order to assess the influence of the magnetisation on the mechanical and viscoelastic properties of the material. The approach adopted in this work followed the Design of Experiment method so that evaluating the influence of the variables and their interactions on the system response is possible. The results highlight a strong dependence on the deformation rate, while the influence of the magnetic field is weak, especially under dynamic shear tests in which the viscous components are predominant.

scholarly journals Experimental viscoelastic properties evaluation, under impact loads and large strain conditions, of coated & uncoated rubber from end-of-life tires

2022 ◽  
pp. 107468
Author(s):  
J. González-Vega ◽  
G. Castillo-López ◽  
J.M. Galindo-Moreno ◽  
S. Guerrero-Porras ◽  
F. García-Sánchez
Keyword(s):  
End Of Life ◽  
Viscoelastic Properties ◽  
Large Strain ◽  
Impact Loads

scholarly journals Nonlinear parametric oscillations of a viscoelastic shallow shell of variable thickness

2019 ◽  
Vol 110 ◽  
pp. 01045 ◽  
Author(s):  
Dadakhon Khodzhaev ◽  
Bakhodir Normuminov ◽  
Yazdan Mustapakulov ◽  
Angela Mottaeva
Keyword(s):  
Variable Thickness ◽  
Viscoelastic Properties ◽  
Shallow Shell ◽  
Dynamic Instability ◽  
Rheological Parameters ◽  
Periodic Load ◽  
Weakly Singular Kernel ◽  
Initial Shape ◽  
Aspect Ratios ◽  
Parametric Oscillations

The problem of parametric oscillations of an isotropic viscoelastic shallow shell of variable thickness under periodic load is considered. It is believed that under the influence of specified load, the shallow shell allows displacements (in particular, deflections), commensurate with its thickness. In a geometrically nonlinear statement, taking into account the viscoelastic properties of material, a mathematical model of the problem has been developed using the classical Kirchhoff-Love hypothesis. Using the Bubnov-Galerkin method based on the polynomial approximation of the deflections, the problem is reduced to the study of the system of integro-differential equations, where time is the independent variable. The solution of the system of integrodifferential equations is determined by the proposed numerical method. Based on this method, a numerical solution algorithm is described. The Koltunov-Rzhanitsyn kernel with three different rheological parameters is chosen as a weakly singular kernel. At the same time, the effect of geometric nonlinearity, viscoelastic properties of material, as well as other physicomechanical and geometric parameters and factors (rheological parameters, thickness, initial shape imperfections, aspect ratios, boundary conditions, excitation coefficient) on the area of dynamic instability is taken into account. The results obtained in this study are in good agreement with the results and data obtained by other authors.

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