scholarly journals Tendon Fascicles Exhibit a Linear Correlation Between Poisson's Ratio and Force During Uniaxial Stress Relaxation

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Shawn P. Reese ◽  
Jeffrey A. Weiss
Keyword(s):  
Stress Relaxation ◽  
Linear Correlation ◽  
Poisson’S Ratio ◽  
Viscoelastic Behavior ◽  
Uniaxial Stress ◽  
Poisson's Ratio ◽  
Lateral Strain ◽  
Sprague Dawley ◽  
Underlying Mechanisms ◽  
Dependent Mechanism

The underlying mechanisms for the viscoelastic behavior of tendon and ligament tissue are poorly understood. It has been suggested that both a flow-dependent and flow-independent mechanism may contribute at different structural levels. We hypothesized that the stress relaxation response of a single tendon fascicle is consistent with the flow-dependent mechanism described by the biphasic theory (Armstrong et al., 1984, “An Analysis of the Unconfined Compression of Articular Cartilage,” ASME J. Biomech. Eng., 106, pp. 165–173). To test this hypothesis, force, lateral strain, and Poisson's ratio were measured as a function of time during stress relaxation testing of six rat tail tendon fascicles from a Sprague Dawley rat. As predicted by biphasic theory, the lateral strain and Poisson's ratio were time dependent, a large estimated volume loss was seen at equilibrium and there was a linear correlation between the force and Poisson's ratio during stress relaxation. These results suggest that the fluid dependent mechanism described by biphasic theory may explain some or all of the apparent viscoelastic behavior of single tendon fascicles.

Direct Measurement of the Time Dependent Poisson’s Ratio in Rat Tail Tendon During Stress Relaxation

2010 ◽  
Author(s):  
Shawn P. Reese ◽  
Jeffrey A. Weiss
Keyword(s):  
Stress Relaxation ◽  
Direct Measurement ◽  
Poisson’S Ratio ◽  
Normal Function ◽  
Poisson's Ratio ◽  
Tensile Creep ◽  
Uniaxial Tensile ◽  
Tail Tendon ◽  
Underlying Mechanisms ◽  
Rat Tail

The viscoelastic behavior of tendons and ligaments contributes to the normal function of these tissues. However, the underlying mechanisms for this behavior are still poorly understood. Although stress and strain in the loading direction have been well studied for uniaxial tensile creep and stress relaxation, data on the lateral contraction during these tests are unavailable. This information is necessary to obtain an understanding of the underlying mechanisms of viscoelasticity. The purpose of this study was to begin filling this gap by providing a direct measurement of the Poisson’s ratio as a function of time in rat tail tendon (RTT) samples during uniaxial stress relaxation testing. A further objective of this study was to determine if there exists a correlation between the Poisson’s ratio and the stress during stress relaxation testing.

scholarly journals Auxetic two-dimensional transition metal selenides and halides

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Jinbo Pan ◽  
Yan-Fang Zhang ◽  
Jingda Zhang ◽  
Huta Banjade ◽  
Jie Yu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Poisson’S Ratio ◽  
2D Materials ◽  
Uniaxial Stress ◽  
Poisson's Ratio ◽  
Two Dimensional ◽  
Future Design ◽  
Metal Metal ◽  
Multiple Materials ◽  
Metal Selenides

Abstract Auxetic two-dimensional (2D) materials provide a promising platform for biomedicine, sensors, and many other applications at the nanoscale. In this work, utilizing a hypothesis-based data-driven approache, we identify multiple materials with remarkable in-plane auxetic behavior in a family of buckled monolayer 2D materials. These materials are transition metal selenides and transition metal halides with the stoichiometry MX (M = V, Cr, Mn, Fe, Co, Cu, Zn, Ag, and X = Se, Cl, Br, I). First-principles calculations reveal that the desirable auxetic behavior of these 2D compounds originates from the interplay between the buckled 2D structure and the weak metal–metal interaction determined by their electronic structures. We observe that the Poisson’s ratio is sensitive to magnetic order and the amount of uniaxial stress applied. A transition from positive Poisson’s ratio (PPR) to negative Poisson’s ratio (NPR) for a subgroup of MX compounds under large uniaxial stress is predicted. The work provides a guideline for the future design of 2D auxetic materials at the nanoscale.

XRD Tensile Test Technique to Measure Mechanical Properties of Micron-Thick Si and TiN Films

2005 ◽  
Vol 297-300 ◽  
pp. 574-580 ◽  
Author(s):  
Takahiro Namazu ◽  
Shozo Inoue ◽  
Daisuke Ano ◽  
Keiji Koterazawa
Keyword(s):  
Mechanical Properties ◽  
Tensile Test ◽  
Partial Pressure ◽  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Poisson's Ratio ◽  
Lateral Strain ◽  
Test Technique ◽  
Tin Films

This paper focuses on investigating mechanical properties of micron-thick polycrystalline titanium nitride (TiN) films. We propose a new technique that can directly measure lateral strain of microscale crystalline specimen by X-ray diffraction (XRD) during tensile test. The XRD tensile test can provide not only Young’s modulus but also Poisson’s ratio of TiN films. Micron-thick TiN films were deposited onto both surfaces of single crystal silicon (Si) specimen by r.f. reactive magnetron sputtering. Young’s modulus and Poisson’s ratio of Si specimen obtained by XRD tensile tests were in good agreement with analytical values. TiN films deposited at Ar partial pressure of 0.7Pa had the average values of 290GPa and 0.36 for Young’s modulus and Poisson’s ratio. The elastic mechanical properties of TiN films gradually decreased down to 220GPa and 0.29 with increasing Ar partial pressure up to 1.0Pa, regardless of film thickness. The change in the film properties with Ar partial pressure would be attributed to the change in the film density.

Effect of Fiber Orientation and Strain Rate on the Nonlinear Uniaxial Tensile Material Properties of Tendon

2003 ◽  
Vol 125 (5) ◽  
pp. 726-731 ◽  
Author(s):  
Heather Anne Lynch ◽  
Wade Johannessen ◽  
Jeffrey P. Wu ◽  
Andrew Jawa ◽  
Dawn M. Elliott
Keyword(s):  
Stress Relaxation ◽  
Strain Rate ◽  
Material Properties ◽  
Poisson’S Ratio ◽  
Constant Strain Rate ◽  
Tensile Tests ◽  
Poisson's Ratio ◽  
Fiber Direction ◽  
Linear Region ◽  
Rate Dependent

Tendons are exposed to complex loading scenarios that can only be quantified by mathematical models, requiring a full knowledge of tendon mechanical properties. This study measured the anisotropic, nonlinear, elastic material properties of tendon. Previous studies have primarily used constant strain-rate tensile tests to determine elastic modulus in the fiber direction. Data for Poisson’s ratio aligned with the fiber direction and all material properties transverse to the fiber direction are sparse. Additionally, it is not known whether quasi-static constant strain-rate tests represent equilibrium elastic tissue behavior. Incremental stress-relaxation and constant strain-rate tensile tests were performed on sheep flexor tendon samples aligned with the tendon fiber direction or transverse to the fiber direction to determine the anisotropic properties of toe-region modulus E0, linear-region modulus (E), and Poisson’s ratio (ν). Among the modulus values calculated, only fiber-aligned linear-region modulus E1 was found to be strain-rate dependent. The E1 calculated from the constant strain-rate tests were significantly greater than the value calculated from incremental stress-relaxation testing. Fiber-aligned toe-region modulus E10=10.5±4.7 MPa and linear-region modulus E1=34.0±15.5 MPa were consistently 2 orders of magnitude greater than transverse moduli (E20=0.055±0.044 MPa,E2=0.157±0.154 MPa). Poisson’s ratio values were not found to be rate-dependent in either the fiber-aligned (ν12=2.98±2.59, n=24) or transverse (ν21=0.488±0.653, n=22) directions, and average Poisson’s ratio values in the fiber-aligned direction were six times greater than in the transverse direction. The lack of strain-rate dependence of transverse properties demonstrates that slow constant strain-rate tests represent elastic properties in the transverse direction. However, the strain-rate dependence demonstrated by the fiber-aligned linear-region modulus suggests that incremental stress-relaxation tests are necessary to determine the equilibrium elastic properties of tendon, and may be more appropriate for determining the properties to be used in elastic mathematical models.

A Multiaxial Stochastic Constitutive Law for Concrete With Dilatancy: Part II—Comparison With Experimental Data

1992 ◽  
Vol 59 (2) ◽  
pp. 289-294 ◽  
Author(s):  
Y. H. Won ◽  
A. Fafitis
Keyword(s):  
Experimental Data ◽  
Elastic Modulus ◽  
Poisson’S Ratio ◽  
Peak Stress ◽  
Concrete Specimen ◽  
Uniaxial Stress ◽  
Constitutive Law ◽  
Poisson's Ratio ◽  
Uniaxial Tensile ◽  
Empirical Formulas

The salient features and concepts of a model developed in Part I of this paper are reviewed. The model is extended to include dilatancy and shear compaction which are determined from uniaxial stress-strain relationships. The parameters of the model are the peak stress, initial elastic modulus, and tangential Poisson’s ratio. The peak stress is assumed equal to the compressive strength of the concrete specimen, the initial elastic modulus and the Poisson’s ratio is calculated by proposed empirical formulas. Predictions of the model compare favorably with experimental data reported by various investigators. Responses of concrete specimens subjected to prescribed triaxial proportional stresses, triaxial proportional strains and stresses, hydrostatic plus stress combinations with loading paths on the deviatoric stress plane, biaxial compressive, biaxial tensile, and uniaxial tensile loadings are predicted and compared with test data. All predictions are satisfactory.

On the “elastic stiffness” in a high-cycle accumulation model — continued investigations

2013 ◽  
Vol 50 (12) ◽  
pp. 1260-1272 ◽  
Author(s):  
Torsten Wichtmann ◽  
Andrzej Niemunis ◽  
Theodoros Triantafyllidis
Keyword(s):  
Stress Relaxation ◽  
Bulk Modulus ◽  
Poisson’S Ratio ◽  
Volumetric Strain ◽  
Fine Sand ◽  
Elastic Stiffness ◽  
Poisson's Ratio ◽  
Initial Stresses ◽  
Cyclic Test ◽  
Membrane Penetration

The high-cycle accumulation (HCA) model proposed by the authors can be used to predict permanent deformations or stress relaxation due to a large number (e.g., several millions) of load cycles with relative small strain amplitudes (<10−3). The predicted stress relaxation depends on the isotropic “elastic stiffness”, [Formula: see text], used in the HCA model. To calibrate the bulk modulus, K, the rate of pore pressure accumulation obtained from an undrained cyclic test and the rate of volumetric strain accumulation measured in a drained cyclic test are compared. Poisson’s ratio, ν, can be determined from the shape of the stress relaxation path measured in an undrained test with anisotropic consolidation stresses and strain cycles. Unfortunately, the calibration of K shown for a medium coarse sand in a previous paper by Wichtmann et al. in 2010 was affected by membrane penetration effects. Consequently, all further studies have been performed on a fine sand for which membrane penetration is negligible. The present paper reports on the new results. The strong pressure dependence of K and its independence from amplitude found in the previous study could be confirmed by the new tests. In addition, the new experimental results reveal a density dependence of K, while the bulk modulus is rather independent of stress ratio. Furthermore, for the first time Poisson’s ratio, ν, used in the HCA model has been calibrated based on tests performed with different amplitudes, densities, and initial stresses.

Improvement of Poisson’s Ratio using Carbon Nanotubes Reinforcement for Laminated Sandwich Plate

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Senbagan ◽  
R. Sarathkumar ◽  
D. Dominic Xavier ◽  
S. Seralathan ◽  
V. Hariram
Keyword(s):  
Carbon Nanotubes ◽  
Poisson’S Ratio ◽  
Longitudinal Strain ◽  
Sandwich Panel ◽  
Sandwich Plate ◽  
Relative Difference ◽  
Poisson's Ratio ◽  
Face Sheet ◽  
Lateral Strain ◽  
Compressive Loads

The focus of this study is to improve the material properties like Poisson's ratio and flexural strength of a sandwich plate by adding carbon nanotubes. A comparative analysis is carried out between sandwich plate with and without addition of carbon nanotubes. Nastran / Patran are the main tools used for this analysis. The experimental work focuses on the behaviour of the sandwich plate while applying tensile and compressive loads. The reduction of displacement in orthogonal sides under compressive stress and tensile stress are observed for carbon nanotubes enriched sandwich plate. This is due to increased face sheet relative difference of lateral strain with longitudinal strain. It is also observed that the mechanical properties of carbon nanotubes enriched sandwich plate are enhanced in comparison to sandwich plate without carbon nanotubes. It is found that, for feasible applications, the sandwich plate enhanced with carbon nanotubes, possess greater face sheet relative difference of lateral strain with longitudinal strain. It is concluded that the Poisson’s ratio for the sandwich panel enriched with carbon nanotubes is advantageous than sandwich panel without carbon nanotubes.

Direct Measurement of Poisson's Ratio in Elastomers

1990 ◽  
Vol 63 (4) ◽  
pp. 473-487 ◽  
Author(s):  
H. P. Kugler ◽  
R. G. Stacer ◽  
C. Steimle
Keyword(s):  
Stress Relaxation ◽  
Strain Rate ◽  
Poisson’S Ratio ◽  
Constant Strain Rate ◽  
Poisson's Ratio ◽  
Relaxation Data ◽  
Optoelectronic System ◽  
Filled Elastomers ◽  
Significant Figures ◽  
Measurement Approach

Abstract Poisson's ratio has been measured in a series of filled elastomers using a novel optoelectronic system. Relative precision of this measurement was found to be approximately 0.7% at 1% strain for this family of materials. The largest contributing error source was determined to be the tolerances that could be obtained in machining the surfaces of the test specimens. As a result of these errors, only three significant figures for Poisson's ratio can be achieved using this measurement approach. Material property tests conducted included constant strain rate and stress relaxation. Constant strain-rate results were used for general characterization, while the stress—relaxation data were employed to investigate time-dependent aspects of Poisson's ratio.

scholarly journals NON-MONOTONICITY, SIGN CHANGES AND OTHER FEATURES OF POISSON'S RATIO EVOLUTION FOR ISOTROPIC LINEAR VISCOELASTIC MATERIALS UNDER TENSION AT CONSTANT STRESS RATES

2019 ◽  
Vol 81 (3) ◽  
pp. 271-291
Author(s):  
A.V. Khokhlov
Keyword(s):  
Poisson’S Ratio ◽  
Poisson Ratio ◽  
Constant Stress ◽  
Stress Rate ◽  
Poisson's Ratio ◽  
Lateral Strain ◽  
Viscoelastic Materials ◽  
Sign Changes ◽  
Material Functions ◽  
Different Types

We study analytically the Boltzmann - Volterra linear constitutive equation for isotropic non-aging viscoelastic media in order to elucidate its capabilities to provide a qualitative simulation of rheological phenomena related to different types of evolution of triaxial strain state and of the lateral contraction ratio (the Poisson ratio) observed in uni-axial tests of viscoelastic materials under tension or compression at constant stress rate. In particular, we consider such effects as increasing, decreasing or non-monotone dependences of lateral strain and Poisson's ratio on time, sign changes and negativity of Poisson's ratio (auxeticity effect) and its stabilization at large times. The viscoelasticity equation implies that the hydrostatic and deviatoric parts of stress and strain tensors don't depend on each other. It is governed by two material functions of a positive real argument (that is shear and bulk creep compliances). Assuming both creep compliances are arbitrary positive, differentiable, increasing and convex up functions on time semi-axis, we analyze general expressions for the Poisson ratio and strain triaxiality ratio (which is equal to volumetric strain divided by deviatoric strain) generated by the viscoelasticity relation under uni-axial tension or compression. We investigate qualitative properties and peculiarities of their evolution in time and their dependences on material functions characteristics. We obtain the universal accurate two-sided bound for the Poisson ratio range and criteria for the Poisson ratio increase or decrease and for extrema existence. We derive necessary and sufficient restrictions on shear and bulk creep compliances providing sign changes of the Poisson ratio and negative values of Poisson's ratio on some interval of time. The properties of the Poisson ratio under tension at constant stress rates found in the study we compare to properties the Poisson ratio evolution under constant stress (in virtual creep tests) and illustrate them using popular classical and fractal models with shear and bulk creep functions each one controlled by three parameters. The analysis carried out let us to conclude that the linear viscoelasticity theory (supplied with common creep functions which are non-exotic from any point of view) is able to simulate qualitatively the main effects associated with different types of the Poisson ratio evolution under tension or compression at constant stress rate except for dependence of Poisson's ratio on stress rate. It is proved that the linear theory can reproduce increasing, decreasing or non-monotone and convex up or down dependences of lateral strain and Poisson's ratio on time and it can provide existence of minimum, maximum or inflection points and sign changes from minus to plus and vice versa and asymptotic stabilization at large times.

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