Lower critical pressure for dynamic stability of a spherical shell

1971 ◽  
Vol 23 (1) ◽  
pp. 337-367
Author(s):  
A. I. Zagustin ◽  
E. A. Zagustin
Keyword(s):  
Spherical Shell ◽  
Dynamic Stability ◽  
Critical Pressure

Nonlinear Stability Analysis of the Vaulted Roofs With Corrosion Defects of Oil Storage Tank

2009 ◽  
Author(s):  
Baosheng Dong ◽  
Xinwei Zhao ◽  
Hongda Chen ◽  
Jinheng Luo ◽  
Zhixin Chen ◽  
...  
Keyword(s):  
Spherical Shell ◽  
Nonlinear Stability ◽  
Storage Tank ◽  
Critical Pressure ◽  
External Pressure ◽  
Shallow Spherical Shell ◽  
Nonlinear Stability Analysis ◽  
Spherical Shells ◽  
Oil Storage ◽  
Oil Storage Tank

The vaulted roofs of oil storage tank are usually designed as the shallow spherical shells subjecting to a uniform external pressure, which have been widely observed that these shallow spherical shells undergo various levels of corrosion in their employing conditions. It is important to assess the stability of these local weaken shallow spherical roofs due to corrosion for preventing them from occurring unexpected buckling failure. In this paper, the uniform eroded part of a shallow spherical oil tank vaulted roof is simplified as a shallow spherical shell with elastic supports. Based on the simplification, a general pathway to calculate the critical pressure of eroded shallow spherical shell is proposed. The modified iteration method considering large deflection of the shell is applied to solve the problem of nonlinear stability of the shallow spherical shells, and then the second-order approximate analytical solution is obtained. The critical pressure calculated by this method is consistent with the classical numerical results and nonlinear finite element method, and the calculation errors are less than 10%. It shows that it is feasible to apply the method proposed here.

Convergence of a thin spherical shell

2007 ◽  
Vol 5 ◽  
pp. 307-323
Author(s):  
S.V. Khabirov ◽  
A.R. Garifullin
Keyword(s):  
Spherical Shell ◽  
Dynamic Stability ◽  
Equations Of Motion ◽  
Asymptotic Formulas ◽  
Precise Solution ◽  
Solution Of Equations ◽  
Initial Stage ◽  
Thin Spherical Shell

The precise solution of equations of motion of a true liquid describing a convergence to the center of a thin spherical shell is considered. At the initial stage prime asymptotic formulas which are used for studying of a dynamic stability in relation to potential indignations are received.

Spherical Shell Sector Acrylic Plastic Windows with 12,000 ft Operational Depth for Submersible Alvin

1976 ◽  
Vol 98 (2) ◽  
pp. 523-536 ◽  
Author(s):  
J. D. Stachiw ◽  
R. Sletten
Keyword(s):  
Stress Distribution ◽  
Spherical Shell ◽  
Critical Pressure ◽  
Catastrophic Failure ◽  
Ocean Bottom ◽  
Uniform Stress ◽  
Short Term ◽  
Single Pass ◽  
Sustained Loading ◽  
The Cost

It has been found that the 90-deg plane conical frustum windows with t/Di = 0.7 ratio in ALVIN submersible can be replaced with 90-deg t/Di = 1 spherical shell sector windows without any modification of window seat flanges. The 90-deg spherical shell sector windows with t/Di = 1.0 possess not only a higher short term critical pressure but also develop more uniform stress distribution during a typical dive to 12,000 ft than the t/Di = 0.7 acrylic conical frustum windows that they replace. The 90-deg t/Di = 1.0 spherical shell sector windows (1) withstood, without catastrophic failure, 100 hr sustained loading to 20,000 psi, (2) 33 pressure cycles of 7-hr duration to 13,500 ft depth without any signs of fatigue, and (3) experienced less than 15,000 μin. strain during a simulated typical prooftest dive to 13,500 ft depth. The 90-deg t/Di = 1 spherical shell sector window presents a 50 percent larger view in water than a 90-deg t/Di = 0.7 conical frustum window that it replaces. This permits the observer inside the submersible to cover visually more ocean bottom during a single pass along the bottom and thus decreases the cost of a typical bottom search mission for a submersible.

Rapid Critical Point Drying of Tissues in a Parr Bomb

1972 ◽  
Vol 30 ◽  
pp. 400-401
Author(s):  
C.A. Baechler ◽  
W. C. Pitchford ◽  
J. M. Riddle ◽  
C.B. Boyd ◽  
H. Kanagawa ◽  
...  
Keyword(s):  
Critical Point ◽  
Critical Pressure ◽  
Soft Tissues ◽  
Biological Tissues ◽  
Critical Temperatures ◽  
Air Drying ◽  
The Past ◽  
Critical Point Drying ◽  
Great Stress ◽  
Infiltration Techniques

Preservation of the topographic ultrastructure of soft biological tissues for examination by scanning electron microscopy has been accomplished in the past by using lengthy epoxy infiltration techniques, or dehydration in ethanol or acetone followed by air drying. Since the former technique requires several days of preparation and the latter technique subjects the tissues to great stress during the phase change encountered during air-drying, an alternate rapid, economical, and reliable method of surface structure preservation was developed. Turnbill and Philpott had used a fluorocarbon for the critical point drying of soft tissues and indicated the advantages of working with fluids having both moderately low critical pressures as well as low critical temperatures. Freon-116 (duPont) which has a critical temperature of 19. 7 C and a critical pressure of 432 psi was used in this study.

Molecular insights on the dynamic stability of peptide nucleic acid functionalized carbon and boron nitride nanotubes

2021 ◽  
Vol 23 (1) ◽  
pp. 219-228
Author(s):  
Nabanita Saikia ◽  
Mohamed Taha ◽  
Ravindra Pandey
Keyword(s):  
Nucleic Acid ◽  
Boron Nitride ◽  
Nucleic Acids ◽  
Dynamic Stability ◽  
Peptide Nucleic Acid ◽  
Rational Design ◽  
Peptide Nucleic Acids ◽  
Boron Nitride Nanotubes ◽  
Molecular Hybrids ◽  
Single Wall Nanotubes

The rational design of self-assembled nanobio-molecular hybrids of peptide nucleic acids with single-wall nanotubes rely on understanding how biomolecules recognize and mediate intermolecular interactions with the nanomaterial's surface.

When Rows Look Like Columns: Dynamic Stability of Grouping by Proximity

2000 ◽  
Author(s):  
Helena Kadlec ◽  
Iris Van Rooij ◽  
Valerie A. Gonzales
Keyword(s):  
Dynamic Stability
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