An Experimental Method for Determining Poisson’s Ratio of Elastomers

1970 ◽  
Vol 92 (3) ◽  
pp. 381-386 ◽  
Author(s):  
Glenn K. Rightmire
Keyword(s):  
Experimental Method ◽  
Poisson’S Ratio ◽  
Poisson's Ratio ◽  
Compliant Surface ◽  
Typical Data ◽  
Load Carrying ◽  
The Common ◽  
Significant Figures ◽  
Sensitive Parameters ◽  
Better Than

One of the most important and sensitive parameters defining the characteristic behavior of compliant-surface, fluid-film bearings has been found to be the value of Poisson’s ratio of the elastomer material—a 1 percent variation in ν in the range of common values produces about a 25 percent change in load carrying capacity. Since values of Poisson’s ratio for the common elastomers are unknown with any degree of accuracy, an experimental method has been devised to measure Poisson’s ratio for typical cases to better than four significant figures. This paper describes the method together with an error analysis and typical data from elastomeric samples.

An Experimental Method to Determine Poisson’s Ratio in a Small Beam Subject to Seismic Excitation

1997 ◽  
Author(s):  
Roberto Caracciolo ◽  
Alessandro Gasparetto ◽  
Marco Giovagnoni
Keyword(s):  
Experimental Method ◽  
Poisson’S Ratio ◽  
Iterative Procedure ◽  
Master Curve ◽  
Seismic Excitation ◽  
Poisson's Ratio ◽  
Strain Gauges ◽  
Frequency Range ◽  
Different Temperatures ◽  
Transverse Strains

Abstract An experimental method to determine Poisson’s ratio in a small beam subject to seismic excitation is presented. Poisson’s ratio is computed by measuring longitudinal and transverse strains by means of electric strain gauges. A first set of tests is carried out with different materials, and it is observed that the measured Poisson’s ratio decreases with frequency. However, to determine whether the observed decrease is true or it is due to an error caused by the plate effect of the beam, a second set of tests at different temperatures is carried out. Then, by applying the reduced variables method, a unique plot for Poisson’s ratio on a much broader frequency range is obtained, which allows to state that the decrease of Poisson’s ratio is true. An iterative procedure is described, which has been developed to gather the curves at different temperatures in a master curve.

Circular Auxetic Plates

2012 ◽  
Vol 29 (1) ◽  
pp. 121-133 ◽  
Author(s):  
T.-C. Lim
Keyword(s):  
Poisson’S Ratio ◽  
Load Distribution ◽  
Point Load ◽  
Poisson's Ratio ◽  
Circular Plates ◽  
Auxetic Materials ◽  
Edge Conditions ◽  
Bending Stresses ◽  
The Common ◽  
Laterally Loaded

AbstractThis paper investigates the suitability of auxetic materials for load-bearing circular plates. It is herein shown that the optimal Poisson's ratio for minimizing the bending stresses is strongly dependent on the final deformed shape, load distribution, and the type of edge supports. Specifically, the use of auxetic material for circular plates is recommended when (a) the plate is bent into a spherical or spherical-like cap, (b) a point load is applied to the center of the plate regardless of the edge conditions, and (c) a uniform load is applied on a simply-supported plate. However, auxetic materials are disadvantaged when a flat plate is to be bent into a saddle-like shell. The optimal Poisson's ratios concept recommended in this paper is useful for providing an added design consideration. In most cases, the use of auxetic materials for laterally loaded circular plates is more advantageous compared to the use of materials with conventional Poisson's ratio, with other factors fixed. This is achieved through materials-based stress re-distribution in addition to the common practices of dimensioning-based stress redistribution and materials strengthening.

scholarly journals Prediction of Fracture Pressure Gradient in Halfaya Oilfield

2019 ◽  
Vol 20 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Neaam F. Hussain ◽  
Faleh H. M. Al Mahdawi
Keyword(s):  
Pressure Gradient ◽  
Field Study ◽  
Poisson’S Ratio ◽  
Poisson's Ratio ◽  
Empirical Methods ◽  
Integrity Test ◽  
Total Cost ◽  
Fracture Pressure ◽  
Well Design ◽  
The Common

   Fracture pressure gradient prediction is complementary in well design and it is must be considered in selecting the safe mud weight, cement design, and determine the optimal casing seat to minimize the common drilling problems. The exact fracture pressure gradient value obtained from tests on the well while drilling such as leak-off test, formation integrity test, cement squeeze ... etc.; however, to minimize the total cost of drilling, there are several methods could be used to calculate fracture pressure gradient classified into two groups: the first one depend on Poisson’s ratio of the rocks and the second is fully empirical methods. In this research, the methods selected are Huubert and willis, Cesaroni I, Cesaroni II, Cesaroni III, Eaton, and Daines where Poisson’s ratio is considered essential here and the empirical methods selected are Matthews and Kelly and Christman. The results of these methods give an approximately match with the previous field study which has been relied upon in drilling the previous wells in the field and Cesaroni I is selected to be the equation that represents the field under study in general. In the shallower formations, Cesaroni I is the best method; while in deepest formations, Eaton, Christman, and Cesaroni I are given a good and approximately matching. The fracture pressure gradient of Halfaya oilfield range is (0.98 to 1.03) psi/ft.

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.

Effect of Carbon Black on Poisson's Ratio of Elastomers

1975 ◽  
Vol 48 (2) ◽  
pp. 246-253 ◽  
Author(s):  
B. P. Holownia
Keyword(s):  
Carbon Black ◽  
Bulk Modulus ◽  
Experimental Method ◽  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Poisson's Ratio ◽  
Carbon Black Content ◽  
Practical Applications ◽  
Incompressible Materials

Abstract The experimental method developed is mostly suitable for measuring K of relatively incompressible materials such as members of the elastomer family. The accuracy of K values are estimated to be within ±3% for all rubber specimens. Its use can be extended to plastics with somewhat reduced accuracy. The results show that bulk modulus K for the four different rubbers tested increases almost linearly with carbon black content while the Young's modulus E increases much more rapidly as shown in Figure 3. It is interesting to note that Poisson's ratio v calculated using K and E does not fall below 0.4940 (Figure 5), and the value of v=0.4997 as quoted in engineering handbooks would be reasonable to use for most practical applications where the carbon black content is not excessive.

Scanning Secondary Electron Microscopy of Myofibrils Using Transmission Techniques

1975 ◽  
Vol 33 ◽  
pp. 556-557
Author(s):  
M. K. Lamvik
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Carbon Films ◽  
Photographic Recording ◽  
Transmission Electron ◽  
Thin Carbon ◽  
The Common ◽  
Scanning Electron ◽  
Better Than ◽  
Cellular Organelles

When observing small objects such as cellular organelles by scanning electron microscopy, it is often valuable to use the techniques of transmission electron microscopy. The common practice of mounting and coating for SEM may not always be necessary. These possibilities are illustrated using vertebrate skeletal muscle myofibrils.Micrographs for this study were made using a Hitachi HFS-2 scanning electron microscope, with photographic recording usually done at 60 seconds per frame. The instrument was operated at 25 kV, with a specimen chamber vacuum usually better than 10-7 torr. Myofibrils were obtained from rabbit back muscle using the method of Zak et al. To show the component filaments of this contractile organelle, the myofibrils were partially disrupted by agitation in a relaxing medium. A brief centrifugation was done to clear the solution of most of the undisrupted myofibrils before a drop was placed on the grid. Standard 3 mm transmission electron microscope grids covered with thin carbon films were used in this study.

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