Young's Modulus, Poisson's Ratio, and Nanoscale Deformation Fields of MEMS Materials

2003 ◽  
Vol 795 ◽  
Author(s):  
I. Chasiotis ◽  
S. W. Cho ◽  
T. A. Friedmann ◽  
J. P. Sullivan
Keyword(s):  
Phase Transformations ◽  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Film Surface ◽  
Local Deformation ◽  
Image Correlation ◽  
Poisson's Ratio ◽  
First Time

ABSTRACTThe mechanical properties of hydrogen-free tetrahedral amorphous diamond-like carbon have been investigated in connection with its elastic and failure properties. Micro-tension specimens of gage thickness of 1.2–1.8 μm and widths of 10 μm or 50 μm have been fabricated by the Sandia National Laboratories (SNL). The mechanical characterization has been conducted via in situ AFM measurements and Digital Image Correlation (DIC) data strain analysis and the local deformation fields of (a) uniform and (b) internally notched tension specimens with acute notches (K=27) have been experimentally obtained. Young's modulus and Poisson's ratio were measured for the first time directly from such small specimens and averaged 750 GPa and v=0.16 respectively, while the tensile strength was found to be very consistent averaging 7.1 GPa. Stressed material domains with smaller dimensions in the vicinity of micronotches exhibited even higher failure strengths reaching 11.5 GPa with limited data scatter. AFM images of in situ tested specimens have indicated sp3 to sp2 phase transformations on the film surface that was subject to ultra-high tensile stresses (>6 GPa). This is the first time these phase transformations are observed during tensile tests of brittle materials.

scholarly journals Experimental Characterization and Modeling Multifunctional Properties of Epoxy/Graphene Oxide Nanocomposites

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2831
Author(s):  
Naresh Kakur ◽  
Kamran A. Khan ◽  
Rehan Umer
Keyword(s):  
Thermal Conductivity ◽  
Graphene Oxide ◽  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Image Correlation ◽  
Poisson's Ratio ◽  
Mechanical And Thermal Properties ◽  
Temperature Dependent ◽  
Frequency Temperature

Thermomechanical modeling of epoxy/graphene oxide under quasi-static and dynamic loading requires thermo-mechanical properties such as Young’s modulus, Poisson’s ratio, thermal conductivity, and frequency-temperature dependent viscoelastic properties. In this study, the effects of different graphene oxide (GO) concentrations (0.05, 0.1, and 0.2 wt%) within an epoxy matrix on several mechanical and thermal properties were investigated. The distribution of GO fillers in the epoxy was investigated using transmission electron microscopy (TEM). The digital image correlation (DIC) technique was employed during the tensile testing to determine Young’s modulus and Poisson’s ratio. Analytical models were used to predict Young’s modulus and thermal conductivity, with an error of less than 13% and 9%, respectively. Frequency–temperature dependent phenomenological models were proposed to predict the storage moduli and loss tangent, with a reasonable agreement with experimental data. A relatively high storage modulus, heat-resistance index (THRI), and thermal conductivity were observed in 0.2 wt% nanocomposite samples compared with pure epoxy and other lower concentration GO nanocomposites. A high THRI and derivative of thermogravimetric analysis peak temperatures (Tm1 and Tm2) were exhibited by adding nano-fillers in the epoxy, which confirms higher thermal stability of nanocomposites than that of pristine epoxy.

An ASM Recommended Practice for Evaluation of Young’s Modulus and Poisson’s Ratio of Thermal Spray Coatings Bonded to a Substrate

2000 ◽  
Author(s):  
J.R. Shadley ◽  
E.F. Rybicki ◽  
Y. Xiong ◽  
R.T.R. McGrann ◽  
A.C. Savarimuthu
Keyword(s):  
Young’S Modulus ◽  
Thermal Spray ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Thermal Spray Coatings ◽  
Poisson's Ratio ◽  
Spray Coatings ◽  
Recommended Practices ◽  
International Thermal Spray

Abstract In situ values of Young's modulus and Poisson's ratio for thermal spray coatings are needed to evaluate properties and characteristics of thermal spray coatings such as residual stresses, in-service stresses, bond strength, fracture toughness, and fatigue crack growth rates. It is important to have methods documented in detail so that people can follow the document and use the methods. Such a document requires more pages than are allowed in conference proceeding and journal papers. Thus, Recommended Practices and Standards describing these methods are needed. Currently, there is not a recommended practice or standard for evaluating Young's modulus and Poisson's ratio for thermal spray coatings. The ASM International Thermal Spray Society has recognized this need and formed a committee on Recommended Practices for Thermal Spray Coatings. This paper describes one of the recommended practices being written by the Mechanical Properties Evaluation Subcommittee of the Recommended Practices Committee. The specimen is a coated substrate in the form of a cantilever beam. The method is easy to use and inexpensive. The equipment needed is a vise or clamping fixture, strain gages, a strain indicator, a micrometer, a ruler, a hanger, and a set of weights. The specimen is easy to machine and spray. The loading is easy to apply and remains constant during readings. The method can be used to evaluate Young's modulus and Poisson's ratio in tension or compression. A description of the method, a verification, and a sensitivity analysis was done and published in Reference [1]. Some of the details of implementing the method and the data sheet are presented here.

Scale effect and impact of discontinuities in the dynamic elastic constants of the Campanian chalk of Bougival (France)

2013 ◽  
Vol 184 (4-5) ◽  
pp. 347-355
Author(s):  
Róbert Porjesz ◽  
Françoise Bergerat
Keyword(s):  
Mechanical Properties ◽  
Rock Mass ◽  
Young’S Modulus ◽  
Elastic Properties ◽  
Scale Effect ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Poisson's Ratio ◽  
Overburden Rock

Abstract Physical properties of in situ rock mass are usually estimated from results obtained through laboratory tests on intact rock samples because the access to in situ rock may be quite challenging. This approach however raises some questions concerning the number of samples needed for reliable result, the validity of the extrapolation of the parameters from centimetre scale to a large rock mass and finally the effect of discontinuities contained in the rock mass. An underground quarry in Bougival with easy access to metre-scale pillars and the possibility to collect large number of samples has been chosen to analyse the scale effect and the anisotropy of the Campanian chalk. Different experiments have been designed to determine the dynamic elastic properties (Young’s modulus and Poisson’s ratio) based on geophysical approaches: ultrasonic measurements on laboratory samples, and “hammer” seismic measurements in situ. The static Young’s modulus and Poisson’s ratio have been determined through uniaxial compression tests on centimetre core samples. Pillars with and without visible discontinuities, as well as with various overburden rock thicknesses, have been chosen in order to analyse the possible impact of different heterogeneities on the elastic properties. Core samples of intact chalk, with 40mm to 100mm diameters, have been studied in laboratory. The high dispersion observed on the different results suggests that if only a few tests are analysed, the conclusions may not be representative. A statistical approach is more appropriate to analyse the mechanical properties of the chalk. The dynamic Young’s Modulus and Poisson’s ratio calculated from laboratory samples (centimetres) and in situ rocks (about ten metres) do not reveal any clear impact of size on these elastic properties. The presence of discontinuities has a major impact on both the dynamic Young’s modulus and Poisson’s ratio. Decreasing values of these properties have been observed where discontinuities (fractures, flints) have been detected. Finally, the overburden rock thickness above the underground quarries (from 14m to 50m) seems to have no effect on the mechanical properties; the uncertainty of the measurements, partly due to the heterogeneity of the chalk mass, is likely to be more important than the effect of load on the pillars.

scholarly journals Geomechanical characterization of mechanical properties and in-situ stresses for predicting wellbore stability of ATG-field, A case study: Niger delta petroleum province, Nigeria

2020 ◽  
Vol 8 (2) ◽  
pp. 126
Author(s):  
Sebastian Abraham Sunu ◽  
Adetola Sunday Oniku ◽  
Osita Chukwudi Meludu ◽  
Chukwuemeka Patrick Abbey
Keyword(s):  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Well Logs ◽  
Poisson's Ratio ◽  
Dynamic Young’S Modulus ◽  
In Situ Stresses ◽  
Dynamic Young's Modulus ◽  
Compressional Velocity

Well logs from ATG- field wells ATG-10 and ATG-11 were calibrated to develop Mechanical Earth Model (MEM) based on elastic parameter, failure parameters, in-situ stresses, pore pressure using well logs to predict wellbore failure. Poisson’s ratio derived from compressional and shear velocities interval transit time and density logs (RHOB), showed that the values ranges from 0.17 to 0.48 and 0.09 to 0.49, and the dynamic Young's Modulus derived from the Compressional and Shear velocity Logs, ranges from 6.0 GPa to 7.8 GPa and 3.6 GPa to 6.6 GPa, the dynamic shear modulus derived from dynamic young’s modulus and Poisson’s ratio which ranges from 3.8 GPa to 5.1 GPa and 2.1 GPa to 5.4 GPa, while the dynamic Bulk modulus ranges from 0.25 GPa to 1.67 GPa and 0.43 GPa to 1.18 GPa for wells ATG-10 and ATG-11 respectively. The calibrated failure parameters or rock strengths derived from compressional velocity logs include: the internal friction angle (ϕ) from Plumb’s correlation, these ranges from 20.869o to 65.5o and 20.869o to 45.61o, Unaxial compressive (UCS) strength ranges from 757.837 psi to 2505.836 psi and 4577.099 psi to 10512.876 psi, cohesion Strength (C) ranges from 205.697 psi to 355.308 psi and 70.652 psi to 390.32 psi and Tensile strength (To) varies from 17.141 psi to 29.609 psi and 5.885 psi to 32.527 psi for well ATG-10 and ATG-11 respectively. The elastic and rock strengths properties vary in a similar trend to the sonic logs as they are derived based on these values. These properties show increasing values with increasing depth, as a result of larger overburden stress, hence lower porosity or high compressional velocity of the formations. However, the elastic properties and formation strength may vary in different formations.  

Applying digital image correlation to wood strands: Influence of loading rate and specimen thickness

Holzforschung ◽  
2010 ◽  
Vol 64 (6) ◽  
Author(s):  
Gi Young Jeong ◽  
Audrey Zink-Sharp ◽  
Daniel P. Hindman
Keyword(s):  
Digital Image Correlation ◽  
Young’S Modulus ◽  
Digital Image ◽  
Poisson’S Ratio ◽  
Loading Rate ◽  
Young's Modulus ◽  
Image Correlation ◽  
Poisson's Ratio ◽  
Specimen Thickness ◽  
Loading Rates

Abstract Previous studies were devoted to various applications of digital image correlation (DIC) to wood and wood-based composites. However, the focus of these studies was qualitative strain distribution. Overall, there is a lack of testing protocols of DIC for quantifying the elastic properties of woody materials. The objective of this study was to investigate the effects of different specimen thicknesses and loading rates on measurement of Young's modulus and Poisson's ratio by DIC. Young's modulus from DIC decreased as thickness increased at a loading rate of 0.254 mm min-1. Comparing the different loading rates at a thickness of 0.794 mm, Young's modulus from DIC was not in agreement with the value obtained by means of the extensometer regardless of loading rate. However, Young's modulus from DIC at a thickness of 0.381 mm and a loading rate of 0.254 mm min-1 was in good agreement with the corresponding Young's modulus obtained by an extensometer. Poisson's ratio measured from different loading rates and specimen thicknesses was not significantly different between the two measurement systems. From the testing arrangement applied for this study, it is recommended that DIC should be applied at a loading rate of 0.254 mm min-1 or slower for strands with a thickness of 0.381 mm or less.

Determination of Poisson's Ratio of Thin low-k Films using Bidirectional Thermal Expansion Measurement

2006 ◽  
Vol 914 ◽  
Author(s):  
Jiping Ye ◽  
Satoshi Shimizu ◽  
Shigeo Sato ◽  
Nobuo Kojima ◽  
Junnji Noro
Keyword(s):  
Thermal Expansion ◽  
Temperature Gradient ◽  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Silicon Oxide ◽  
Young's Modulus ◽  
Polymer Materials ◽  
Poisson's Ratio ◽  
Thermal Expansion Measurement ◽  
Low K

AbstractA recently developed bidirectional thermal expansion measurement (BTEM) method was applied to different types of low-k films to substantiate the reliability of the Poisson's ratio found with this technique and thereby to corroborate its practical utility. In this work, the Poisson's ratio was determined by obtaining the temperature gradient of the biaxial thermal stress from substrate curvature measurements, the temperature gradient of the whole thermal expansion strain along the film thickness from x-ray reflectivity (XRR) measurements, and reduced modulus of the film from nanoindentation measurements. For silicon oxide-based SiOC film having a thickness of 382.5 nm, the Poisson's ratio, Young's modulus and thermal extension coefficient (TEC) were determined to be Vf = 0.26, αf =21 ppm/K and Ef =9,7 GPa. These data are close to the levels of metals and polymers rather than the levels of fused silicon oxide, which is characterized by Vf = 0.17 and Er = 69.6 GPa. The alkyl component in the silicon oxide-based framework is thought to act as an agent in reducing the modulus and elevating the Poisson's ratio in SiOC low-k materials. In the case of an organic polymer SiLK film with a thickness of 501.5 nm, the Poisson's ratio, Young's modulus and TEC were determined to be Vf = 0.39, αf =74 ppm/K and Er =3.1 GPa, which are in the typical range of V= 0.34~0.47 with E =1.0~10 GPa for polymer materials. From the viewpoint of the relationship between the Poisson's ratio and Young's modulus as classified by different material types, the Poisson's ratios found for the silicon oxide-based SiOC and organic SiLK films are reasonable values, thereby confirming that BTEM is a reliable and effective method for evaluating the Poisson's ratio of thin films.

Measurement of Young's Modulus and Poisson's Ratio of Thin Film by Combination of Bulge Test and Nano-Indentation

2008 ◽  
Vol 33-37 ◽  
pp. 969-974 ◽  
Author(s):  
Bong Bu Jung ◽  
Seong Hyun Ko ◽  
Hun Kee Lee ◽  
Hyun Chul Park
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Applied Pressure ◽  
Indentation Test ◽  
Poisson's Ratio ◽  
Bulge Test ◽  
Nano Indentation

This paper will discuss two different techniques to measure mechanical properties of thin film, bulge test and nano-indentation test. In the bulge test, uniform pressure applies to one side of thin film. Measurement of the membrane deflection as a function of the applied pressure allows one to determine the mechanical properties such as the elastic modulus and the residual stress. Nano-indentation measurements are accomplished by pushing the indenter tip into a sample and then withdrawing it, recording the force required as a function of position. . In this study, modified King’s model can be used to estimate the mechanical properties of the thin film in order to avoid the effect of substrates. Both techniques can be used to determine Young’s modulus or Poisson’s ratio, but in both cases knowledge of the other variables is needed. However, the mathematical relationship between the modulus and Poisson's ratio is different for the two experimental techniques. Hence, achieving agreement between the techniques means that the modulus and Poisson’s ratio and Young’s modulus of thin films can be determined with no a priori knowledge of either.

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