scholarly journals A Theoretical and Experimental Investigation of Creep Problems With Variable Temperature

1976 ◽  
Vol 43 (4) ◽  
pp. 639-644 ◽  
Author(s):  
A. R. S. Ponter ◽  
M. H. Walter
Keyword(s):  
Experimental Investigation ◽  
Strain Hardening ◽  
Variable Temperature ◽  
Short Time Scale ◽  
Rapid Cycling ◽  
Reference Stress ◽  
Thermoelastic Stresses ◽  
Short Time ◽  
Theory And Experiment ◽  
Good Agreement

Rapid cycling solutions are presented for a simple two-bar structure subjected to variable temperature. Three constitutive relationships are considered, nonlinear viscous, strain-hardening and Bailey-Orowan models which describe differing aspects of the creep of metals. It is shown that the solutions for the viscous and strain-hardening relations are essentially similar and possess distinct reference stress histories over ranges of the governing parameters. The presence of recovery in the Bailey-Orowan model causes a distinctly different mode of behavior. Experimental results on a simulated two-bar structure are presented, under conditions where the strain-hardening hypothesis may be expected to be most relevant. Good agreement is obtained between theory and experiment although the presence of anelastic creep, with a short time scale, tends to reduce the effective thermoelastic stresses.

Theoretical and Experimental Investigation on Forming Limit for TNW700 Titanium Alloy

2014 ◽  
Vol 622-623 ◽  
pp. 340-346 ◽  
Author(s):  
Bao Sheng Liu ◽  
Wei Wu ◽  
Xiu Quan Han
Keyword(s):  
Experimental Investigation ◽  
Titanium Alloy ◽  
High Temperature ◽  
Forming Limit ◽  
Minor Strain ◽  
Resistant Material ◽  
Dimple Rupture ◽  
Short Time ◽  
Fractographic Observation ◽  
Good Agreement

Forming limit is identified to evaluate the formability of sheet metal. The in-plane limit strains of sheets are plotted in a diagram with coordinates of major strain vs. minor strain. TNW700 titanium alloy is a high temperature resistant material. The products made of TNW700 can be used in a long serving period at 500°C, short time at 700°C. In this work, the forming limit of TNW700 will be investigated in theoretical and experimental ways. The experiment to test limit strains was carried out at 750°C under different loading paths. Marciniak – Kuczynski (M-K) model was calculated with Swift constitutive equations to predict the curves of limit strains. The effect of the groove angle on forming limit is that, the same angle on both sides of centerline determines the same FLC, and the limit points shift from left side to right side. The experiment shows that, the formability of TNW700 is not excellent, and it is lower than that of TC4 and TA15 at the same condition. The comparison shows that the curve predicted by M-K model is in a good agreement with that at plane strain, however higher than that in both sides. The fractographic observation shows that the fracture mode of TNW700 is dimple rupture.

A Viscoplastic Theory With Anisotropic Hardening and Its Application to Pressure-Shear Plate Impact Experiments

1985 ◽  
Vol 52 (3) ◽  
pp. 629-633 ◽  
Author(s):  
A. Gilat
Keyword(s):  
Strain Hardening ◽  
Anisotropic Hardening ◽  
Plate Impact ◽  
Hardening Model ◽  
Commercially Pure ◽  
Shear Plate ◽  
Alpha Titanium ◽  
Impact Experiments ◽  
Theory And Experiment ◽  
Good Agreement

An elastic/viscoplastic theory that includes anisotropic strain hardening is presented. The theory is a combination of the elastic/viscoplastic formulation of Perzyna [4] and the anisotropic hardening model for time-independent plasticity of Mroz [6]. The theory is used in the analysis of pressure-shear plate impact experiments on commercially pure alpha titanium. Good agreement between theory and experiment is observed.

Laser interferometric galvanostatic studies in the Zn/ZnSO4/Zn system with gelled electrolyte short time electrolysis

1983 ◽  
Vol 61 (10) ◽  
pp. 2316-2320 ◽  
Author(s):  
R. N. O'Brien ◽  
W. Michalik
Keyword(s):  
Parallel Plate ◽  
Liquid Electrolyte ◽  
Second Law ◽  
Transient Conditions ◽  
Short Time ◽  
Laser Interferometric ◽  
Short Times ◽  
Theory And Experiment ◽  
Good Agreement

Electrolysis in the system Zn/ZnSO4/Zn with gelled electrolyte was followed for short times to allow use of the first term only of the solution to Fick's Second Law for transient conditions. Sufficiently good agreement was found between theory and experiment to confirm that no convection occurred in the gelled electrolyte. Similarly sufficiently good agreement with liquid electrolyte runs confirmed that no convection occurred in parallel plate, horizontal electrodes when the cathode was over the anode. The conductivity of the gelled electrolyte was about 11% lower than the liquid electrolyte.

The vibration of ring-stiffened prolate domes under external water pressure

2003 ◽  
Vol 217 (2) ◽  
pp. 173-185
Author(s):  
C T F Ross ◽  
A P F Little ◽  
L Chasapides ◽  
J Banks ◽  
D Attanasio
Keyword(s):  
Finite Element Method ◽  
Experimental Investigation ◽  
Finite Element ◽  
Water Pressure ◽  
The Finite Element Method ◽  
Resonant Frequencies ◽  
External Water Pressure ◽  
External Water ◽  
Theory And Experiment ◽  
Good Agreement

The paper presents a theoretical and an experimental investigation into the free vibration of three ring-stiffened prolate domes in air and under external water pressure. The theoretical investigation was via the finite element method where a solid fluid mesh was used to model the water surrounding each dome. Good agreement was found between theory and experiment. Both the theory and the experiment found that, as the external water pressure was increased, the resonant frequencies decreased.

Experimental Investigation of Gas-Particle Flow Trajectories and Velocities in an Axial Flow Turbine Stage

1972 ◽  
Author(s):  
W. Tabakoff ◽  
A. Hamed ◽  
M. F. Hussein
Keyword(s):  
Experimental Investigation ◽  
Theoretical Analysis ◽  
Pressure Distribution ◽  
High Speed ◽  
Axial Flow ◽  
Particle Flow ◽  
Blade Surface ◽  
Turbine Stage ◽  
Theory And Experiment ◽  
Good Agreement

This paper describes the results from an investigation of the gas-particle flow trajectories, velocities and pressure distribution in an axial flow turbine stage. A gas-particle flow cascade tunnel and high-speed photographic techniques were used to conduct the experimental investigation. The pressure distribution on the blade surface was measured and compared with the theoretical analysis, the results exhibiting good agreement between the developed theory and experiment.

Periodic Variations in the Coronal Green Line Intensity and their Connection with the White-light Coronal Structures

2000 ◽  
Vol 179 ◽  
pp. 197-200
Author(s):  
Milan Minarovjech ◽  
Milan Rybanský ◽  
Vojtech Rušin
Keyword(s):  
Time Resolution ◽  
White Light ◽  
Short Time Scale ◽  
High Time Resolution ◽  
Green Line ◽  
Periodic Intensity ◽  
Coronal Green Line ◽  
Significant Intensity ◽  
Short Time ◽  
Coronal Structures

AbstractWe present an analysis of short time-scale intensity variations in the coronal green line as obtained with high time resolution observations. The observed data can be divided into two groups. The first one shows periodic intensity variations with a period of 5 min. the second one does not show any significant intensity variations. We studied the relation between regions of coronal intensity oscillations and the shape of white-light coronal structures. We found that the coronal green-line oscillations occur mainly in regions where open white-light coronal structures are located.

Experimental investigation and modelling of light scattering in a-Si:H solar cells deposited on glass/ZnO:Al substrates

2002 ◽  
Vol 715 ◽  
Author(s):  
J. Krc ◽  
M. Zeman ◽  
O. Kluth ◽  
F. Smole ◽  
M. Topic
Keyword(s):  
Surface Roughness ◽  
Experimental Investigation ◽  
Solar Cells ◽  
Angular Distribution ◽  
Light Scattering ◽  
Optical Model ◽  
Distribution Functions ◽  
Interface Roughness ◽  
Scattering Parameters ◽  
Good Agreement

AbstractThe descriptive scattering parameters, haze and angular distribution functions of textured ZnO:Al transparent conductive oxides with different surface roughness are measured. An approach to determine the scattering parameters of all internal interfaces in p-i-n a-Si:H solar cells deposited on the glass/ZnO:Al substrates is presented. Using the determined scattering parameters as the input parameters of the optical model, a good agreement between the measured and simulated quantum efficiencies of the p-i-n a-Si:H solar cells with different interface roughness is achieved.

Nondiffusive Brownian Motion Studied by Diffusing-Wave Spectroscopy

1989 ◽  
Vol 177 ◽  
Author(s):  
D. J. Pine ◽  
D. A. Weitz ◽  
D. J. Durian ◽  
P. N. Pusey ◽  
R. J. A. Tough
Keyword(s):  
Autocorrelation Function ◽  
Colloidal Particles ◽  
Scattered Light ◽  
Short Time Scale ◽  
Velocity Autocorrelation Function ◽  
Velocity Autocorrelation ◽  
Power Law Decay ◽  
Brownian Particles ◽  
Short Time ◽  
Surrounding Fluid

ABSTRACTOn a short time scale, Brownian particles undergo a transition from initially ballistic trajectories to diffusive motion. Hydrodynamic interactions with the surrounding fluid lead to a complex time dependence of this transition. We directly probe this transition for colloidal particles by measuring the autocorrelation function of multiply scattered light and observe the effects of the slow power-law decay of the velocity autocorrelation function.

scholarly journals On the Short Time Scale Evolutionary History of the Contact Binary VW Cephei

1998 ◽  
Vol 11 (1) ◽  
pp. 396-396
Author(s):  
I. Pustylnik
Keyword(s):  
Evolutionary History ◽  
Light Curves ◽  
Published Data ◽  
Short Time Scale ◽  
Flare Activity ◽  
Considerable Portion ◽  
History Of ◽  
Contact Binary ◽  
Elongation Phase ◽  
Short Time

We study the short-time evolutionary history of the well-known contact binary VW Cep. Our analysis is based partly on the numerous UBV lightcurves obtained at Tartu Observatory, IUE spectra, and samples from the published data. Special attention is given to the effects of asymmetry of the light curves. A higher degree of asymmetry outside the eclipses along with the significant displacements of the brightness maxima in respect to the elongation phase is interpreted as evidence that a considerable portion of the flaring source is concentrated close to the neck connecting the components. We discuss the nature of asymmetry in terms of possible mass exchange and the flare activity and compare the results of our model computations with the record of orbital period variations over the last 60 years.

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