Elastoviscous Properties of Amorphous Polymers in the Transition Region. I.

1952 ◽  
Vol 25 (4) ◽  
pp. 751-758
Author(s):  
J. Bischoff ◽  
E. Catsiff ◽  
A. V. Tobolsky
Keyword(s):  
Experimental Data ◽  
Transition Region ◽  
Master Curve ◽  
Analytical Procedure ◽  
Relaxation Modulus ◽  
Amorphous Polymers ◽  
Great Accuracy ◽  
Characteristic Relaxation Time ◽  
Region I ◽  
Analytical Expressions

Abstract Experimental data on the stress-relaxation modulus Er,T(t) of a GR-S gum vulcanizate at a series of temperatures in the transition region are presented, and a “master curve” of log Q(t/K) vs. log (t/K) is thereby constructed. The characteristic relaxation time, K, for each temperature is defined and tabulated. A distinctive temperature, Td, is observed at which the activation energy for K is a maximum. Analytical expressions are given which describe the GR-S master-curve with great accuracy. The same analytical procedure can be successfully applied to data previously obtained for polymethyl methacrylate. A reduced equation is proposed which describes the time and temperature dependence of Q(t/K) in the transition region for both polymers.

Elastoviscous Properties of Amorphous Polymers in the Transition Region. I

1952 ◽  
Vol 74 (13) ◽  
pp. 3378-3381 ◽  
Author(s):  
J. Bischoff ◽  
E. Catsiff ◽  
A. V. Tobolsky
Keyword(s):  
Transition Region ◽  
Amorphous Polymers ◽  
Region I

Pressure, Frictional Resistance, and Flow Characteristics of the Partially Wetted Rotating Disk

1968 ◽  
Vol 90 (2) ◽  
pp. 395-404 ◽  
Author(s):  
H. N. Ketola ◽  
J. M. McGrew
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Pressure Gradient ◽  
Flow Characteristics ◽  
Frictional Resistance ◽  
Rotating Disk ◽  
Practical Applications ◽  
Stationary Wall ◽  
Spacing Ratio ◽  
Analytical Expressions

A theory of the partially wetted rotating disk is described and experimental data presented which verify the application of this theory in practical applications. Four different flow regimes may be identified according to the value of the disk Reynolds number and the spacing ratio between the disk and stationary wall. The analytical expressions for prediction of the pressure gradient developed and the frictional resistance are uniquely determined by the disk Reynolds number, spacing ratio, and the degree of wetting of the disk.

scholarly journals Correlation between Paris function parameters to crack velocity for Alumina ceramics

2011 ◽  
Vol 8 (2) ◽  
pp. 326-332
Author(s):  
Baghdad Science Journal
Keyword(s):  
Experimental Data ◽  
Crack Growth ◽  
Exponential Function ◽  
Crack Velocity ◽  
Alumina Ceramic ◽  
Velocity Versus ◽  
Rate Theory ◽  
Alumina Ceramics ◽  
Region I ◽  
Different Grain Size

The question about the existence of correlation between the parameters A and m of the Paris function is re-examined theoretically for brittle material such as alumina ceramic (Al2O3) with different grain size. Investigation about existence of the exponential function which fit a good approximation to the majority of experimental data of crack velocity versus stress intensity factor diagram. The rate theory of crack growth was applied for data of alumina ceramics samples in region I and making use of the values of the exponential function parameters the crack growth rate theory parameters were estimated.

Obtaining shear relaxation modulus and creep compliance of linear viscoelastic materials from instrumented indentation using axisymmetric indenters of power-law profiles

2009 ◽  
Vol 24 (10) ◽  
pp. 3013-3017 ◽  
Author(s):  
Yang-Tse Cheng ◽  
Fuqian Yang
Keyword(s):  
Inverse Problem ◽  
Laplace Transform ◽  
Power Law ◽  
Creep Compliance ◽  
Relaxation Modulus ◽  
Instrumented Indentation ◽  
Loading Paths ◽  
Linear Viscoelastic ◽  
Shear Relaxation ◽  
Analytical Expressions

Using Laplace transform, we solve the inverse problem of obtaining the shear relaxation modulus and creep compliance of linear viscoelastic solids from indentation by axisymmetric indenters of power-law profiles. We identify several simple, though nontrivial, loading paths for carrying out indentation measurements such that the inverse problem has analytical solutions. We show that the shear relaxation modulus and creep compliance may be readily obtained using the newly derived analytical expressions together with proposed indentation loading paths.

scholarly journals A physics-based approach of deep interseismic creep for viscoelastic strike-slip earthquake cycle models

2019 ◽  
Vol 220 (1) ◽  
pp. 79-95
Author(s):  
Lucile Bruhat
Keyword(s):  
Surface Deformation ◽  
Slip Rate ◽  
Strike Slip ◽  
Dynamic Rupture ◽  
Crust And Upper Mantle ◽  
Slip Rates ◽  
Region I ◽  
Best Fitting ◽  
Time Invariant ◽  
Analytical Expressions

SUMMARY Most geodetic inversions of surface deformation rates consider the depth distribution of interseismic fault slip-rate to be time invariant. However, some numerical simulations show downdip penetration of dynamic rupture into regions with velocity-strengthening friction, with subsequent updip propagation of the locked-to-creeping transition. Recently, Bruhat and Segall developed a new method to characterize interseismic slip rates, that allows slip to penetrate up dip into the locked region. This simple model considered deep interseismic slip as a crack loaded at its downdip end, and provided analytical expressions for stress drop within the crack, slip and slip rate along the fault. This study extends this approach to strike-slip fault environments, and includes coupling of creep to viscoelastic flow in the lower crust and upper mantle. I use this model to investigate interseismic deformation rates along the Carrizo Plain section of the San Andreas fault. This study reviews possible models, elastic and viscoelastic, for fitting horizontal surface rates. Using this updated approach, I develop a physics-based solution for deep interseismic creep which accounts for possible slow vertical propagation, and investigate how it improves the fit of the horizontal deformation rates in the Carrizo Plain region. I found solutions for fitting the surface deformation rates that allow for reasonable estimates for earthquake rupture depth and coseismic displacement and improves the overall fit to the data. Best-fitting solutions present half-space relaxation time around 70 yr, and very low propagation speeds, less than a metre per year, suggesting a lack of creep propagation.

Tunnelströme durch Al2O3-Schichten bei Kontakten verschiedener Austrittsarbeiten

1964 ◽  
Vol 19 (5) ◽  
pp. 573-579 ◽  
Author(s):  
H. G. Hurst ◽  
W. Ruppel
Keyword(s):  
Experimental Data ◽  
Work Function ◽  
Applied Voltage ◽  
Tunneling Current ◽  
Insulating Films ◽  
Tunneling Currents ◽  
Analytical Expressions

The tunneling current through Al2O3-layers of a thickness varying between 30 and 100 Å was measured for In-Al2O3-Al, Al-Al2O3-Al, and Au-Al2O3-Al layer cells. The dependence of the observed current on the applied voltage, the thickness of the Al2O03-layer, and temperature is in agreement with an analysis of tunneling currents through insulating films by STRATTON. By comparing the experimental data with the analytical expressions the following values are derived for the metal-Al2O3 work function: In: 0.55 eV; Al: 0.77 eV; Au: 1.6 eV.

A straightforward determination of fluid viscosity and density using microcantilevers: From experimental data to analytical expressions

2011 ◽  
Vol 172 (1) ◽  
pp. 40-46 ◽  
Author(s):  
M. Youssry ◽  
N. Belmiloud ◽  
B. Caillard ◽  
C. Ayela ◽  
C. Pellet ◽  
...  
Keyword(s):  
Experimental Data ◽  
Fluid Viscosity ◽  
Analytical Expressions

Transition Region of Nuclear Vessel Steels: Master Curve Approach Using Small Punch Notched Specimens

2017 ◽  
Vol 734 ◽  
pp. 77-86
Author(s):  
Roberto Lacalle ◽  
David Andrés ◽  
José Alberto Álvarez ◽  
Federico Gutiérrez-Solana
Keyword(s):  
Transition Region ◽  
Master Curve ◽  
Nuclear Reactor ◽  
Structural Integrity ◽  
Charpy Impact ◽  
Vessel Steel ◽  
New Approach ◽  
Small Punch ◽  
Impact Tests ◽  
Integrity Assessments

The behaviour of the materials in ductile-brittle transition region must be known when performing structural integrity assessments of nuclear reactor vessels working under the effects of neutron irradiation. The characterisation of this region has been usually carried out by means of Charpy impact tests. Just during last few years new approaches based on direct fracture mechanics tests have begun to be used. In most of these cases, the Master Curve methodology, which allows the transition region to be characterised using only one parameter (T0 reference temperature), has been employed. In this paper the transition region of two materials –one vessel steel and one common structural steel-has been characterised by means of Small Punch Tests. First of all, this zone has been characterised using conventional specimens and the results were compared with those of Charpy impact tests. Finally a new approach based on the use of notched Small Punch samples together with Master Curve methodology has been proposed.

Transient kinetics of nucleation and crystallization: Part II. Crystallization

1991 ◽  
Vol 6 (10) ◽  
pp. 2097-2102 ◽  
Author(s):  
G. Shi ◽  
J.H. Seinfeld
Keyword(s):  
Experimental Data ◽  
Large Time ◽  
Volume Fraction ◽  
Time Dependent ◽  
Transient Kinetics ◽  
Amorphous Phases ◽  
Time Limits ◽  
The Stability ◽  
Analytical Expressions ◽  
Kinetics Of

Analytical expressions for the time-dependent crystallized volume fraction are derived from new results for the transient rate of nucleation reported in Part I. Conventional formulations that have been used in interpreting crystallization experimental data and for assessing the stability of amorphous phases are shown to be large time limits of the newly derived expressions. An approach for assessing the stability of an amorphous phase is proposed.

Sign in / Sign up

Export Citation Format

Share Document