Failure From Creep as Influenced by the State of Stress

1943 ◽  
Vol 10 (4) ◽  
pp. A202-A212
Author(s):  
W. Siegfried
Keyword(s):  
United States ◽  
Experimental Data ◽  
Grain Boundaries ◽  
Three Dimensional ◽  
The United States ◽  
Dimensional System ◽  
State Of Stress ◽  
Brittle Fractures ◽  
Combined Action ◽  
Three Dimensional System

Abstract As early as 1912, it was pointed out by Rosenhain and Ewen (1) that the behavior of metals at high temperatures could be explained by the combined action of the crystals and the so-called grain boundaries. This theory was also made use of later to explain problems in connection with creep phenomena (2). The author discusses subsequent studies in the United States and Germany, relating to the occurrence of brittle fractures in metals after long periods of time. With the aid of the Rosenhain-Ewen conceptions, he attempts to reconcile discrepancies between recent observations on the occurrence of inter-crystalline fractures after long test periods. His evaluation of the theories cited offers an explanation of various phenomena which previously could not be interpreted, and also furnishes a basis for determining the risk of failure with creep in a three-dimensional system of stress. He concludes that the problem of calculating the strength of a material subjected to creep is actually solved only when the metallurgist and the steel manufacturer are in a position to furnish the designer with complete experimental data enabling him to predict failure for all systems of stress occurring in practice.

scholarly journals A Comparison of Simulation’s Results with Experiment on Water Mitigation of an Explosion

1999 ◽  
Vol 6 (2) ◽  
pp. 73-80 ◽  
Author(s):  
W.K Chong ◽  
K.Y. Lam ◽  
K.S. Yeo ◽  
G.R. Liu ◽  
O.Y. Chong
Keyword(s):  
United States ◽  
Experimental Data ◽  
Finite Element ◽  
United States Army ◽  
Peak Pressure ◽  
Three Dimensional ◽  
The United States ◽  
Small Scale ◽  
Finite Element Code ◽  
Good Comparison

This paper presents a comparison of simulation’s results with the experimental data from a series of small-scale tests conducted by Joachim and Lunderman of the United States Army Engineer Waterways Experiment Station. The purpose of the experiments was to evaluate the effect of water as a mean of reducing airblast pressure from accidental explosions in underground magazines. In the present study, a series of three-dimensional numerical calculations were conducted using a Multimaterial Eulerian Finite Element Code. Results from the numerical simulations show good comparison with the experimental data for the case with and without water. Our simulation ascertains the mitigation effects of water in reducing the maximum peak pressure and impulse density due to an explosion.

scholarly journals NON-UNIFORM ALONGSHORE CURRENTS

1976 ◽  
Vol 1 (15) ◽  
pp. 39 ◽  
Author(s):  
Michael R. Gourlay
Keyword(s):  
Experimental Data ◽  
Current System ◽  
Three Dimensional ◽  
Dimensional System ◽  
Circulation Patterns ◽  
Alongshore Current ◽  
Set Up ◽  
Current Systems ◽  
Three Dimensional System ◽  
Nonuniform Wave

Alongshore gradients of breaker height have been shown to significantly influence the velocities and circulation patterns of nearshore current systems. Experimental data from an idealized laboratory experiment shows that the form of the nonuniform wave generated current system resulting from diffraction behind an offshore breakwater is essentially determined by the beach-breakwater geometry while its magnitude depends upon the wave height. Furthermore the current may produce significant increases in the magnitude of the wave set-up within the three dimensional system. For the case investigated, where the alongshore gradient of breaker height is comparatively large, the maximum mean alongshore current velocity is not greatly affected by bottom resistance and may be computed for plunging breakers from a relation of the following form.

Inner-product theory calculations for some rational potentials in a three-dimensional system

1996 ◽  
Vol 74 (1-2) ◽  
pp. 4-9
Author(s):  
M. R. M. Witwit
Keyword(s):  
Energy Levels ◽  
Three Dimensional ◽  
Inner Product ◽  
Dimensional System ◽  
Product Technique ◽  
Special Cases ◽  
Wide Range ◽  
Perturbation Parameters ◽  
Three Dimensional System ◽  
Range Of Values

The energy levels of a three-dimensional system are calculated for the rational potentials,[Formula: see text]using the inner-product technique over a wide range of values of the perturbation parameters (λ, g) and for various eigenstates. The numerical results for some special cases agree with those of previous workers where available.

The influence of mean shear on Alfvén-internal wave propagation

1976 ◽  
Vol 15 (2) ◽  
pp. 197-222
Author(s):  
R. J. Hartman
Keyword(s):  
Three Dimensional ◽  
Dimensional System ◽  
Linear Wave ◽  
Mean Flow ◽  
Wave Processes ◽  
Initial Value ◽  
Initial Wave ◽  
Wave Phenomena ◽  
Three Dimensional System

This paper uses the general solution of the linearized initial-value problem for an unbounded, exponentially-stratified, perfectly-conducting Couette flow in the presence of a uniform magnetic field to study the development of localized wave-type perturbations to the basic flow. The two-dimensional problem is shown to be stable for all hydrodynamic Richardson numbers JH, positive and negative, and wave packets in this flow are shown to approach, asymptotically, a level in the fluid (the ‘isolation level’) which is a smooth, continuous, function of JH that is well defined for JH < 0 as well as JH > 0. This system exhibits a rich complement of wave phenomena and a variety of mechanisms for the transport of mean flow kinetic and potential energy, via linear wave processes, between widely-separated regions of fluid; this in addition to the usual mechanisms for the absorption of the initial wave energy itself. The appropriate three-dimensional system is discussed, and the role of nonlinearities on the development of localized disturbances is considered.

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