scholarly journals Stress Analysis for Design of Electromagnetic Launchers

1988 ◽  
Vol 110 (3) ◽  
pp. 395-400 ◽  
Author(s):  
E. P. Fahrenthold ◽  
D. R. Peterson ◽  
J. H. Price ◽  
A. Y. Wu
Keyword(s):  
Structural Analysis ◽  
Stress Analysis ◽  
Pulsed Power ◽  
Power Supplies ◽  
High Current ◽  
Stress Concentrations ◽  
Electromagnetic Launchers ◽  
Electromagnetic Launcher ◽  
Order Of Magnitude ◽  
Very High

The recent development of very high current pulsed power supplies provides an opportunity for order of magnitude improvements in electromagnetic launcher performance. Consideration of design objectives and constraints suggests that a ceramic-steel construction offers significant advantages over conventional composite-steel railguns. Structural analysis of such a system focuses upon material specific stress concentrations produced by dynamic and asymmetric electromagnetic loads.

Design of Pressure Vessel Cascades for Electromagnetic Launchers

1989 ◽  
Vol 111 (3) ◽  
pp. 326-331
Author(s):  
E. P. Fahrenthold
Keyword(s):  
High Energy ◽  
Pressure Vessels ◽  
Pulsed Power ◽  
Power Supplies ◽  
High Energy Density ◽  
Electromagnetic Launchers ◽  
Electromagnetic Launcher ◽  
Very High Energy ◽  
Very High

The relatively recent development of very high-energy density pulsed power supplies has motivated a renewed interest in the structural design of electromagnetic launchers. Cascade design electromagnetic launcher pressure vessels offer convenient maintenance access to high wear rate components of the structure while satisfying an unusual combination of electromagnetic, strength, and preloading constraints imposed on the system designer. Analysis for design of such structures focuses on the accurate characterization of fluid-structure interaction under dynamic asymmetric loading.

Mechanical Design of Small-Bore Electromagnetic Launchers

1991 ◽  
Vol 113 (1) ◽  
pp. 92-101
Author(s):  
A. K. Thakore ◽  
E. P. Fahrenthold
Keyword(s):  
Mechanical Performance ◽  
Mechanical Design ◽  
Pressure Vessels ◽  
Pulsed Power ◽  
Power Supplies ◽  
Fatigue Reliability ◽  
Electromagnetic Launchers ◽  
Design Changes ◽  
Low Modulus ◽  
Fast Fracture

The development of special-purpose pressure vessels for small-bore, high-velocity electromagnetic launchers has characteristically employed low modulus composites and bolted steel frames. Such designs exhibit low structural stiffness, particularly at high operating currents. Although these designs can be modified to improve mechanical performance, numerical modeling results indicate that basic changes are needed to allow operation at the high bore pressures characteristic of newly developed pulsed power supplies. The indicated design changes introduce a requirement for fast fracture and fatigue reliability analysis of low tensile strength ceramic parts.

scholarly journals Origin and Application of the Twinned Calcite Strain Gauge

Geosciences ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 296
Author(s):  
Richard H. Groshong
Keyword(s):  
Stress Analysis ◽  
Strain Gauge ◽  
Strain Tensor ◽  
Three Dimensional ◽  
Constant Strain Rate ◽  
Axis Orientation ◽  
Order Of Magnitude ◽  
Rate Experiment ◽  
Strain Axis ◽  
Expected Values

This paper is a personal account of the origin and development of the twinned-calcite strain gauge, its experimental verification, and its relationship to stress analysis. The method allows the calculation of the three-dimensional deviatoric strain tensor based on five or more twin sets. A minimum of about 25 twin sets should provide a reasonably accurate result for the magnitude and orientation of the strain tensor. The opposite-signed strain axis orientation is the most accurately located. Where one strain axis is appreciably different from the other two, that axis is generally within about 10° of the correct value. Experiments confirm a magnitude accuracy of 1% strain over the range of 1–12% axial shortening and that samples with more than 40% negative expected values imply multiple or rotational deformations. If two deformations are at a high angle to one another, the strain calculated from the positive and negative expected values separately provides a good estimate of both deformations. Most stress analysis techniques do not provide useful magnitudes, although most provide a good estimate of the principal strain axis directions. Stress analysis based on the number of twin sets per grain provides a better than order-of-magnitude approximation to the differential stress magnitude in a constant strain rate experiment.

scholarly journals Observational manifestations of ‘cosmological dinosaurs’ at redshifts z ∼ 20

2021 ◽  
Vol 503 (2) ◽  
pp. 3081-3088
Author(s):  
V K Dubrovich ◽  
Yu N Eroshenko ◽  
S I Grachev
Keyword(s):  
Black Hole ◽  
Atomic Hydrogen ◽  
Radiation Transfer ◽  
Ring Width ◽  
High Mass ◽  
Primordial Black Hole ◽  
Array Type ◽  
Local Sources ◽  
Order Of Magnitude ◽  
Very High

ABSTRACT We consider a primordial black hole of very high mass, $10^9\!-\!10^{10}\, \mathrm{M}_\odot$, surrounded by the dark matter and bayonic halo at redshifts z ∼ 20 without any local sources of energy release. Such heavy and concentrated objects in the early Universe were previously called ‘cosmological dinosaurs’. Spectral distribution and spatial variation of the brightness in the 21-cm line of atomic hydrogen are calculated with the theory of radiation transfer. It is shown that a narrow and deep absorption arises in the form of the spherical shell around the primordial black hole at the certain radius. The parameters of this shell depend almost exclusively on the mass of the black hole. The angular diameter 18 arcsec of the absorption ring at z ∼ 20 is well within the current technical possibilities of the Square Kilometre Array type telescopes. But the observation of the ring width itself requires an order of magnitude better resolution.

High voltage, high current stabilized power supplies

1962 ◽  
Vol 39 (2) ◽  
pp. 99-99
Author(s):  
Electronic Machine Co Ltd.
Keyword(s):  
High Voltage ◽  
Power Supplies ◽  
High Current
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