Express Estimation of the Poisson Ratio of Friction Surfaces

2021 ◽  
Vol 42 (3) ◽  
pp. 185-187
Author(s):  
M. M. Matlin ◽  
V. A. Kazankin ◽  
E. N. Kazankina
Keyword(s):  
Poisson Ratio ◽  
Friction Surfaces

Postmortem and in situ TEM methods to study the mechanism of failure in controlled-morphology high-impact polystrene resin

1996 ◽  
Vol 54 ◽  
pp. 178-179
Author(s):  
R. C. Cieslinski ◽  
M. T. Dineen ◽  
J. L. Hahnfeld
Keyword(s):  
Poisson Ratio ◽  
Acrylonitrile Butadiene Styrene ◽  
High Impact ◽  
In Situ Tem ◽  
Styrene Copolymers ◽  
Controlled Morphology ◽  
Point Bend ◽  
Mechanism Of Failure ◽  
Impact Energies

Advanced Styrenic resins are being developed throughout the industry to bridge the properties gap between traditional HIPS (High Impact Polystyrene) and ABS (Acrylonitrile-Butadiene-Styrene copolymers) resins. These new resins have an unprecedented balance of high gloss and high impact energies. Dow Chemical's contribution to this area is based on a unique combination of rubber morphologies including labyrinth, onion skin, and core-shell rubber particles. This new resin, referred as a controlled morphology resin (CMR), was investigated to determine the toughening mechanism of this unique rubber morphology. This poster will summarize the initial studies of these resins using the double-notch four-point bend test of Su and Yee, tensile stage electron microscopy, and Poisson Ratio analysis of the fracture mechanism.

Comparison of the viscoelastic penetration and tensile behaviour of poly(methyl acrylate) and poly(ethyl acrylate)

1979 ◽  
Vol 44 (6) ◽  
pp. 1942-1948 ◽  
Author(s):  
Jaroslav Hrouz ◽  
Michal Ilavský ◽  
Ivan Havlíček ◽  
Karel Dušek
Keyword(s):  
Methyl Acrylate ◽  
Poisson Ratio ◽  
Young Modulus ◽  
Ethyl Acrylate ◽  
Sample Volume ◽  
Viscoelastic Behaviour ◽  
Tensile Behaviour ◽  
Temperature Superposition ◽  
Main Transition

The viscoelastic penetration and tensile behaviour of poly(methyl acrylate) and poly(ethyl acrylate) in the main transition region have been investigated. It was found that the time-temperature superposition could be carried out in the case of the penetration viscoelastic behaviour; the temperature dependence of the penetration and tensile shift factors was the same. The superimposed curves of the penetration and Young modulus allowed us to calculate the dependence of the Poisson ratio and thus to characterize the change in sample volume with deformation. It was demonstrated that the penetration method of determination of the viscoelastic behaviour is equivalent to the tensile method.

scholarly journals Analysis of High-Friction Surface Texture with Respect to Friction and Wear

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 758
Author(s):  
Cibi Pranav ◽  
Minh-Tan Do ◽  
Yi-Chang Tsai
Keyword(s):  
Friction Coefficient ◽  
Surface Texture ◽  
Safety Concern ◽  
Future Research ◽  
Scanning System ◽  
Novel Approach ◽  
Texture Parameters ◽  
Aggregate Loss ◽  
Friction Surfaces ◽  
The Impact

High Friction Surfaces (HFS) are applied to increase friction capacity on critical roadway sections, such as horizontal curves. HFS friction deterioration on these sections is a safety concern. This study deals with characterization of the aggregate loss, one of the main failure mechanisms of HFS, using texture parameters to study its relationship with friction. Tests are conducted on selected HFS spots with different aggregate loss severity levels at the National Center for Asphalt Technology (NCAT) Test Track. Friction tests are performed using a Dynamic Friction Tester (DFT). The surface texture is measured by means of a high-resolution 3D pavement scanning system (0.025 mm vertical resolution). Texture data are processed and analyzed by means of the MountainsMap software. The correlations between the DFT friction coefficient and the texture parameters confirm the impact of change in aggregates’ characteristics (including height, shape, and material volume) on friction. A novel approach to detect the HFS friction coefficient transition based on aggregate loss, inspired by previous works on the tribology of coatings, is proposed. Using the proposed approach, preliminary outcomes show it is possible to observe the rapid friction coefficient transition, similar to observations at NCAT. Perspectives for future research are presented and discussed.

Methods to isolate retrograde and prograde Rayleigh-wave signals

2019 ◽  
Vol 219 (2) ◽  
pp. 975-994 ◽  
Author(s):  
Gabriel Gribler ◽  
T Dylan Mikesell
Keyword(s):  
Rayleigh Wave ◽  
Time Domain ◽  
Fundamental Mode ◽  
Poisson Ratio ◽  
Low Frequency ◽  
Wave Dispersion ◽  
Low Frequencies ◽  
Retrograde Motion ◽  
Mode Identification ◽  
Time Frequency

SUMMARY Estimating shear wave velocity with depth from Rayleigh-wave dispersion data is limited by the accuracy of fundamental and higher mode identification and characterization. In many cases, the fundamental mode signal propagates exclusively in retrograde motion, while higher modes propagate in prograde motion. It has previously been shown that differences in particle motion can be identified with multicomponent recordings and used to separate prograde from retrograde signals. Here we explore the domain of existence of prograde motion of the fundamental mode, arising from a combination of two conditions: (1) a shallow, high-impedance contrast and (2) a high Poisson ratio material. We present solutions to isolate fundamental and higher mode signals using multicomponent recordings. Previously, a time-domain polarity mute was used with limited success due to the overlap in the time domain of fundamental and higher mode signals at low frequencies. We present several new approaches to overcome this low-frequency obstacle, all of which utilize the different particle motions of retrograde and prograde signals. First, the Hilbert transform is used to phase shift one component by 90° prior to summation or subtraction of the other component. This enhances either retrograde or prograde motion and can increase the mode amplitude. Secondly, we present a new time–frequency domain polarity mute to separate retrograde and prograde signals. We demonstrate these methods with synthetic and field data to highlight the improvements to dispersion images and the resulting dispersion curve extraction.

An Overall Approach for Microcrack and Inhomogeneity Toughening in Brittle Solids

1999 ◽  
Vol 15 (2) ◽  
pp. 57-68
Author(s):  
Huang Hsing Pan
Keyword(s):  
Poisson Ratio ◽  
Crack Density ◽  
Mean Field ◽  
Analytic Form ◽  
Density Parameter ◽  
Brittle Solids ◽  
The Matrix ◽  
Microcrack Toughening ◽  
Average Quantity ◽  
The Mean

ABSTRACTBased on the weight function theory and Hutchinson's technique, the analytic form of the toughness change near a crack-tip is derived. The inhomogeneity toughening is treated as an average quantity calculated from the mean-field approach. The solutions are suitable for the composite materials with moderate concentration as compared with Hutchinson's lowest order formula. The composite has the more toughened property if the matrix owns the higher value of the Poisson ratio. The composite with thin-disc inclusions obtains the highest toughening and that with spheres always provides the least effective one. For the microcrack toughening, the variations of the crack shape do not significantly affect the toughness change if the Budiansky and O'Connell crack density parameter is used. The explicit forms for three types of the void toughening and two types of the microcrack toughening are also shown.

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