Dependence of Compression Modulus on Poisson's Ratio

1973 ◽  
Vol 46 (1) ◽  
pp. 286-293 ◽  
Author(s):  
S. R. Moghe ◽  
H. F. Neff
Keyword(s):  
Analytical Solutions ◽  
Empirical Formula ◽  
Poisson’S Ratio ◽  
Compression Modulus ◽  
Experimental Results ◽  
Poisson's Ratio ◽  
Shape Factors ◽  
Thixotropic Behavior

Abstract The experimental results and the widely used empirical formula (E/EApp)=(1+βS2)−1+(E/B) for the compression modulus are compared with analytical solutions obtained by Moghe and Neff. It is shown that the empirical formula does not represent the data adequately, particularly for large and small shape factors. It is also shown that the variation in β in the empirical formula arises due to the inadequacy of the representation rather than the thixotropic behavior as claimed.

Poisson's ratio of plywood measured by tension test

Holzforschung ◽  
2009 ◽  
Vol 63 (5) ◽  
Author(s):  
Hiroshi Yoshihara
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Poisson’S Ratio ◽  
Tension Test ◽  
Experimental Results ◽  
Poisson's Ratio ◽  
Element Analysis ◽  
Young’S Moduli ◽  
Tension Tests ◽  
Finite Element Calculations

Abstract In this research, Poisson's ratio of plywood as obtained by a tension test was examined by varying the width of the specimen. The tension tests were conducted on five-plywood of lauan (Shorea sp.) with various widths, and Young's moduli and Poisson's ratios of the specimens were measured. Finite element calculations were independently conducted. A comparison of the experimental results with those of finite element analysis revealed that Young's modulus could be obtained properly when the width of the plywood strip varied. In contrast, the width of the plywood strip should be large enough to determine Poisson's ratio properly.

scholarly journals Analytical relationships for re-entrant honeycombs

2020 ◽  
Author(s):  
Reza Hedayati ◽  
Naeim Ghavidelnia
Keyword(s):  
Yield Stress ◽  
Analytical Solutions ◽  
Poisson’S Ratio ◽  
Poisson's Ratio ◽  
Negative Poisson’S Ratio ◽  
Fe Method ◽  
Wide Range ◽  
Unit Cells ◽  
Negative Poisson's Ratio ◽  
Internal Angle

Mechanical metamaterials have emerged in the last few years as a new type of artificial material which show properties not usually found in nature. Such unprecedented properties include negative stiffness, negative Poisson’s ratio, negative compressibility and fluid-like behaviors. Unlike normal materials, materials with negative Poisson’s ratio (NPR), also known as auxetics, shrink laterally when a compressive load is applied to them. The 2D re-entrant honeycombs are the most prevalent auxetic structures and many studies have been dedicated to study their stiffness, large deformation behavior, and shear properties. Analytical solutions provide inexpensive and quick means to predict the behavior of 2D re-entrant structures. There have been several studies in the literature dedicated to deriving analytical relationships for hexagonal honeycomb structures where the internal angle θ is positive (i.e. when the structure has positive Poisson’s ratio). It is usually assumed that such solutions also work for corresponding re-entrant unit cells. The goal of this study was to find out whether or not the analytical relationships obtained in the literature for θ>0 are also applicable to 2D-reentrant structures (i.e. when θ<0). Therefore, this study focused on unit cells with a wide range of internal angles from very negative to very positive values. For this aim, new analytical relationships were obtained for hexagonal honeycombs with possible negativity in the internal angle θ in mind. Numerical analyses based on finite element (FE) method were also implemented to validate and evaluate the analytical solutions. The results showed that, as compared to analytical formulas presented in the literature, the analytical solutions derived in this work give the most accurate results for elastic modulus, Poisson’s ratio, and yield stress. Moreover, some of the formulas for yield stress available in the literature fail to be valid for negative ranges of internal angle (i.e. for auxetics). However, the yield stress results of the current study demonstrated good overlapping with numerical results in both the negative and positive domains of θ.

Temperature Buildup in Bonded Rubber Blocks Due to Hysteresis

1977 ◽  
Vol 50 (1) ◽  
pp. 186-193
Author(s):  
B. P. Holownia
Keyword(s):  
Temperature Distribution ◽  
Cyclic Loading ◽  
Theoretical Analysis ◽  
Poisson’S Ratio ◽  
Experimental Results ◽  
Poisson's Ratio ◽  
The Third ◽  
Significant Figure ◽  
Rubber Block

Abstract The comparison between theoretical and experimental results of the temperature distribution in bonded cyclindrical rubber blocks due to compressive cyclic loading was largely dependent on the value of Poisson's ratio. It was found that, for thin rubber blocks (D/h>6), the third significant figure in the value of v appreciably altered the temperature distribution, while for thick blocks (D/h<4), the same change in v had much smaller effect on the temperature distribution within the rubber block. The theoretical analysis used in the paper can easily be adapted for blocks of different geometries, and hence the temperature distribution within a desirable limit can be achieved by changing the geometry of the rubber block.

Anisotropic Poisson's ratio and compression modulus of cortical bone determined by speckle interferometry

2007 ◽  
Vol 40 (2) ◽  
pp. 252-264 ◽  
Author(s):  
R. Shahar ◽  
P. Zaslansky ◽  
M. Barak ◽  
A.A. Friesem ◽  
J.D. Currey ◽  
...  
Keyword(s):  
Cortical Bone ◽  
Poisson’S Ratio ◽  
Compression Modulus ◽  
Speckle Interferometry ◽  
Poisson's Ratio

An approximate analysis of infinitesimal deformations of bonded elastic mounts

1988 ◽  
Vol 23 (3) ◽  
pp. 115-120 ◽  
Author(s):  
M H B M Shariff
Keyword(s):  
Explicit Form ◽  
Elastic Material ◽  
Poisson’S Ratio ◽  
Shape Factor ◽  
Theoretical Solution ◽  
Experimental Results ◽  
Poisson's Ratio ◽  
Approximate Analysis ◽  
Theoretical Investigations ◽  
Infinitesimal Deformations

An approximate simple theoretical solution is developed for infinitesimal plane and axisymmetric strain deformations for blocks of elastic material with Poisson's ratio between 0 and 0.5 bonded to rigid end plates. The explicit form of solution, developed for shape factor, S, between 0 and ∞, is easy to use and compares well with published experimental results. It is also comparable with previous theoretical investigations and expected behaviour.

scholarly journals Effect of Different Yarn Combinations on Auxetic Properties of Plied Yarns

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mine Akgun ◽  
Recep Eren ◽  
Fatih Suvari ◽  
Tugba Yurdakul
Keyword(s):  
Polyvinyl Chloride ◽  
Poisson’S Ratio ◽  
Tensile Modulus ◽  
Experimental Results ◽  
Poisson's Ratio ◽  
Yarn Twist ◽  
Twist Level ◽  
Negative Poisson's Ratio ◽  
Yarn Structure ◽  
Plied Yarn

Abstract This study presents the effects of a novel plied yarn structure consisting of different yarn components and yarn twist levels on the Poisson's ratio and auxetic behavior of yarns. The plied yarn structures are formed with bulky and soft yarn components (helical plied yarn [HPY], braided yarn, and monofilament latex yarn) and stiff yarn components (such as high tenacity [HT] and polyvinyl chloride [PVC]-coated polyester yarns) to achieve auxetic behavior. Experimental results showed that as the level of yarn twist increased, the Poisson's ratios and the tensile modulus values of the plied yarns decreased, but the elongation values increased. A negative Poisson's ratio (NPR) was obtained in HT–latex and PVC–latex plied yarns with a low twist level. The plied yarns formed with braid–HPY and braid–braid components gave partial NPR under tension. A similar result was achieved for yarns with HT–latex and PVC–latex components. Since partial NPR was seen in novel plied yarns with braided and HPY components, it is concluded that yarns formed with bulky–bulky yarn components could give an auxetic performance under tension.

scholarly journals Modelling of Auxetic Woven Structures for Composite Reinforcement

Textiles ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 1-15
Author(s):  
Shivangi Shukla ◽  
Bijoya Kumar Behera ◽  
Rajesh Kumar Mishra ◽  
Martin Tichý ◽  
Viktor Kolář ◽  
...  
Keyword(s):  
Analytical Model ◽  
Poisson’S Ratio ◽  
Axial Strain ◽  
Experimental Results ◽  
Poisson's Ratio ◽  
Actual Performance ◽  
Bending Modulus ◽  
Woven Structures ◽  
Error Percentage ◽  
Composite Reinforcement

The current research is focused on the design and development of auxetic woven structures. Finite element analysis based on computational modeling and prediction of axial strain as well as Poisson’s ratio was carried out. Further, an analytical model was used to calculate the same parameters by a foldable zig-zag geometry. In the analytical model, Poisson’s ratio is based on the crimp percentage, bending modulus, yarn spacing, and coefficient of friction. In this yarn, properties and fabric parameters were also considered. Experimental samples were evaluated for the actual performance of the defined auxetic material. Auxetic fabric was developed with foldable strips created in a zig-zag way in the vertical (warp) direction. It is based on the principle that when the fabric is stretched, the unfolding of the folds takes place, leading to an increase in transverse dimensions. Both the analytical and computational models gave close predictions to the experimental results. The fabric with foldable strips created in a zig-zag way in the vertical (warp) direction produced negative Poisson’s ratio (NPR), up to 8.7% of axial strain, and a maximum Poisson’s ratio of −0.41 produced at an axial strain of around 1%. The error percentage in the analytical model was 37.14% for the experimental results. The computational results also predict the Poisson’s ratio with an error percentage of 22.26%. Such predictions are useful for estimating the performance of auxetic woven structures in composite reinforcement. The auxetic structure exhibits remarkable stress-strain behavior in the longitudinal as well as transverse directions. This performance is useful for energy absorption in composite reinforcement.

Effect of Poisson's ratio on compression modulus

1968 ◽  
Vol 3 (2) ◽  
pp. 142-145 ◽  
Author(s):  
P B Lindley
Keyword(s):  
Shear Modulus ◽  
Bulk Modulus ◽  
Poisson’S Ratio ◽  
Marked Effect ◽  
Compression Modulus ◽  
Poisson's Ratio ◽  
Compressive Deformation ◽  
Similar Magnitude ◽  
High Bulk ◽  
Low Shear

Contributions to a compressive deformation can result from change of shape and change of size. For most materials these two contributions are of similar magnitude. For materials such as rubber which have a low shear modulus but a relatively high bulk modulus any restriction on their freedom to change shape can have a very marked effect on their stiffness in compression. Poisson's ratio is used to relate the relative magnitudes of shear and bulk moduli.

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