scholarly journals Asymmetric vibrations and chaos in spherical caps under uniform time-varying pressure fields

2021 ◽  
Author(s):  
Iarriccio Giovanni ◽  
Zippo Antonio ◽  
Pellicano Francesco
Keyword(s):  
Time Varying ◽  
Pressure Fields ◽  
Spherical Caps

scholarly journals Asymmetric Vibrations and Chaos in Spherical Caps under Uniform Time-varying Pressure Fields

2021 ◽  
Author(s):  
Giovanni Iarriccio ◽  
Antonio Zippo ◽  
Francesco Pellicano
Keyword(s):  
Equations Of Motion ◽  
Ritz Method ◽  
Excitation Frequency ◽  
Lagrange Equations ◽  
Reduced Order ◽  
Pressure Fields ◽  
Time Histories ◽  
Implicit Solver ◽  
Spherical Caps ◽  
External Excitation Frequency

Abstract This paper presents a study on nonlinear asymmetric vibrations in shallow spherical caps under pressure loading. The Novozhilov’s nonlinear shell theory is used for modelling the structural strains. A reduced-order model is developed through the Rayleigh-Ritz method and Lagrange equations. The equations of motion are numerically integrated using an implicit solver. The bifurcation scenario is addressed by varying the external excitation frequency. The occurrence of asymmetric vibrations related to quasi-periodic and chaotic motion is shown through the analysis of time histories, spectra, Poincaré maps, and phase planes.

Interface motion during recrystallization of amorphous NiSi2

1990 ◽  
Vol 48 (4) ◽  
pp. 524-525
Author(s):  
J. L. Batstone ◽  
D.A. Smith
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Amorphous Film ◽  
Nucleation And Growth ◽  
Recrystallization Process ◽  
Amorphous Films ◽  
Interface Motion ◽  
Si Substrates ◽  
Spherical Caps ◽  
Crystal Interfaces

Recrystallization of amorphous NiSi2 involves nucleation and growth processes which can be studied dynamically in the electron microscope. Previous studies have shown thatCoSi2 recrystallises by nucleating spherical caps which then grow with a constant radial velocity. Coalescence results in the formation of hyperbolic grain boundaries. Nucleation of the isostructural NiSi2 results in small, approximately round grains with very rough amorphous/crystal interfaces. In this paper we show that the morphology of the rccrystallizcd film is dramatically affected by variations in the stoichiometry of the amorphous film.Thin films of NiSi2 were prepared by c-bcam deposition of Ni and Si onto Si3N4, windows supported by Si substrates at room temperature. The base pressure prior to deposition was 6 × 107 torr. In order to investigate the effect of stoichiomctry on the recrystallization process, the Ni/Si ratio was varied in the range NiSi1.8-2.4. The composition of the amorphous films was determined by Rutherford Backscattering.

Pressure fields investigation by LPS technology on the aerospacecraft model

1994 ◽  
Vol 4 (11) ◽  
pp. 2317-2327 ◽  
Author(s):  
A. O. Andreev ◽  
A. P. Bukov ◽  
M. W. lpatov ◽  
S. V. Kabin ◽  
P. D. Nushtaev ◽  
...  
Keyword(s):  
Pressure Fields

Time-varying Macroeconomic Risk of Real Estate Returns

2016 ◽  
Author(s):  
Felix Schindler ◽  
Bertram Steininger ◽  
Tim Kroencke
Keyword(s):  
Real Estate ◽  
Time Varying ◽  
Macroeconomic Risk ◽  
Real Estate Returns
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