The vibration of a corrugated carbon fibre pressure vessel under external hydrostatic pressure

2000 ◽  
Vol 214 (10) ◽  
pp. 1299-1311 ◽  
Author(s):  
C T F Ross ◽  
A P F Little
Keyword(s):  
Carbon Fibre ◽  
Water Pressure ◽  
Periodic Excitation ◽  
The Finite Element Method ◽  
External Hydrostatic Pressure ◽  
Surrounding Water ◽  
Resonant Frequencies ◽  
External Water Pressure ◽  
External Water ◽  
Good Agreement

The paper presents a theoretical and an experimental investigation into the vibration of a corrugated carbon fibre cylinder in air and under external water pressure. The theoretical investigation was via the finite element method, where both the shell and the surrounding water were modelled with axisymmetric finite elements. In the case of the shell, the element allowed for orthotropicity and in the case of the water, the element was a solid element with an isoparametric cross-section. Good agreement was found between experiment and theory for both the vibration in air and the vibration under external water pressure. The results showed that as the external water pressure was increased, the resonant frequencies decreased. This appeared to agree with previous findings that a form of dynamic buckling could occur when the vibration eigenmode was the same form as the buckling eigenmode, in response to a periodic excitation force.

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.

The vibration of ring-reinforced circular cylinders under external water pressure

1998 ◽  
Vol 212 (4) ◽  
pp. 299-306 ◽  
Author(s):  
C T F Ross ◽  
W D Richards
Keyword(s):  
Finite Element Method ◽  
Water Pressure ◽  
External Pressure ◽  
Circular Cylinders ◽  
The Finite Element Method ◽  
Similar Form ◽  
Surrounding Water ◽  
Resonant Frequencies ◽  
External Water Pressure ◽  
External Water

The paper reports on an experimental and a theoretical investigation into the vibration of three ring-stiffened circular cylinders under external water pressure. The theoretical analysis was via the finite element method, where both the structure and the surrounding water were modelled using finite elements. Comparison between experiment and theory was good, and showed that the resonant frequencies decreased with increasing external pressure. The results also showed that there was a possibility of a form of dynamic buckling, when the vibration eigenmodes became of similar form to the static buckling eigenmodes.

The Vibration of Ring-Stiffened Cones Under External Water Pressure

1994 ◽  
Vol 208 (3) ◽  
pp. 177-185 ◽  
Author(s):  
C T F Ross ◽  
W D Richards
Keyword(s):  
Finite Element Method ◽  
Experimental Investigation ◽  
Water Pressure ◽  
The Finite Element Method ◽  
Surrounding Water ◽  
Conical Shells ◽  
External Water Pressure ◽  
Thin Walled ◽  
External Water ◽  
Good Agreement

This paper describes a theoretical and an experimental investigation into the vibration of three ring-stiffened thin-walled conical shells, under external water pressure. The theoretical investigation was via the finite element method for both the shell structure and the surrounding water. Various fluid meshes were chosen, and a relatively simple one showed good agreement between experiment and theory.

Vibrations of Circular Cylindrical Shells under External Water Pressure

1992 ◽  
Vol 206 (2) ◽  
pp. 79-86 ◽  
Author(s):  
C T F Ross ◽  
T Johns ◽  
R M Stanton
Keyword(s):  
Water Pressure ◽  
Cylindrical Shells ◽  
Shell Element ◽  
The Finite Element Method ◽  
Applied Water ◽  
Resonant Frequencies ◽  
External Water Pressure ◽  
Circular Cylindrical Shells ◽  
External Water ◽  
Surrounding Fluid

A theoretical and an experimental investigation was made on the vibration of three machined circular cylindrical shells under external water pressure. The theoretical investigation was based on the finite element method, where the shell was modelled by a truncated thin-walled conical shell element and the surrounding fluid by an annular element which had a cross-section in the form of an eight-node isoparametric quadrilateral. Comparison between theory and experiment was good and showed that the resonant frequencies decreased with an increase in the externally applied water pressure.

Vibration of a thin-walled carbon fibre corrugated circular cylinder under external water pressure

2006 ◽  
Vol 44 (5) ◽  
pp. 542-553 ◽  
Author(s):  
Carl T.F. Ross ◽  
Andrew P.F. Little ◽  
Philipp Köster ◽  
Giles Tewkesbury
Keyword(s):  
Circular Cylinder ◽  
Carbon Fibre ◽  
Water Pressure ◽  
External Water Pressure ◽  
Thin Walled ◽  
External Water

Vibration Analysis of Submerged Submarine Pressure Hull

2011 ◽  
Vol 133 (1) ◽  
Author(s):  
Seyed Khalil Shariati ◽  
Saeed Mahjob Mogadas
Keyword(s):  
Vibration Analysis ◽  
Water Pressure ◽  
External Pressure ◽  
Pressure Vessels ◽  
Launch Vehicles ◽  
The Finite Element Method ◽  
Structural Applications ◽  
Ballistic Missiles ◽  
External Water Pressure ◽  
External Water

Ring stiffened cylindrical shells are used in many structural applications, such as pressure vessels, submarine hulls, aircrafts, launch vehicles, and waterborne ballistic missiles. Most of these structures are required to operate while subjected to some form of dynamic loading and some of these can be quite severe. Submerged structures, such as submarines, torpedoes, and waterborne missiles, are all subjected to external pressure and are required to operate in a variety of environments where they can be subjected to different loads and conditions. Therefore, the analysis of the dynamic characteristics of these shells under external water pressure is crucial to ensure safe and successful designs. Therefore, in this research, we have considered their vibration analysis. To do this, we have considered the finite element method for vibration analysis of submerged structure and finally by using ANSYS software. We analyzed the free vibration of some models, which have been presented in some papers. After confirmation of the results, we have extended this method to analysis of imaginary submerged pressure hull of submarine.

scholarly journals Analysis of Tunnel Water Inrush Considering the Influence of Surrounding Rock Permeability Coefficient by Excavation Disturbance and Ground Stress

2021 ◽  
Vol 11 (8) ◽  
pp. 3645
Author(s):  
Helin Fu ◽  
Pengtao An ◽  
Long Chen ◽  
Guowen Cheng ◽  
Jie Li ◽  
...  
Keyword(s):  
Permeability Coefficient ◽  
Water Pressure ◽  
Water Inrush ◽  
Surrounding Rock ◽  
Water Inflow ◽  
Calculation Error ◽  
External Water Pressure ◽  
Ground Stress ◽  
External Water ◽  
Inflow Prediction

Affected by the coupling of excavation disturbance and ground stress, the heterogeneity of surrounding rock is very common. Presently, treating the permeability coefficient as a fixed value will reduce the prediction accuracy of the water inflow and the external water pressure of the structure, leading to distortion of the prediction results. Aiming at this problem, this paper calculates and analyzes tunnel water inflow when considering the heterogeneity of permeability coefficient of surrounding rock using a theoretical analysis method, and compares with field data, and verifies the rationality of the formula. The research shows that, when the influence of excavation disturbance and ground stress on the permeability coefficient of surrounding rock is ignored, the calculated value of the external water force of the tunnel structure is too small, and the durability and stability of the tunnel are reduced, which is detrimental to the safety of the structure. Considering the heterogeneity of surrounding rock, the calculation error of water inflow can be reduced from 27.3% to 13.2%, which improves the accuracy of water inflow prediction to a certain extent.

Control of arterial pressure in aquatic sea snakes

1983 ◽  
Vol 244 (1) ◽  
pp. R66-R73 ◽  
Author(s):  
H. B. Lillywhite ◽  
F. H. Pough
Keyword(s):  
Arterial Pressure ◽  
Blood Volume ◽  
Water Pressure ◽  
Cardiovascular Responses ◽  
Physiological Regulation ◽  
Sea Snakes ◽  
Head Up Tilt ◽  
External Water Pressure ◽  
External Water ◽  
Head Level

Cardiovascular responses to head-up tilt, acutely graded hemorrhage, and pharmacologic stimulation by principal autonomic drugs were studied in four species of marine snakes, principally Aipysurus laevis (family Hydrophiidae). Arterial pressure varied inversely with tilt angle and blood volume deficit in conscious snakes outside of water, indicating that physiological regulation was poor or lacking. Calculated arterial pressures at head level typically diminished to zero in A. laevis tilted to angles greater than or equal to 30 degrees. Arterial pressure (corrected for external water pressure) did not change when these snakes were tilted in seawater. Changes of arterial pressure induced by tilt, blood loss, or autonomic drugs elicited reflex adjustments in heart activity, but the magnitude of these responses was less than that observed in terrestrial species of snake. It is concluded that baroreflexes are present but comparatively ineffective in sea snakes. Snakes tolerated large losses of blood volume, and extravascular fluids were absorbed into the circulation during hemorrhage; both hemorrhage and estimated hemodilution volumes exceeded 100% of the initial blood volume in Acalyptophis peronii. Thus, in marine snakes major fluid shifts between nonvascular and vascular compartments significantly compensate hypovolemia but, because of minor autonomic adjustments, do not result in a well-regulated arterial pressure.

scholarly journals A multicentered comparison of measurements obtained with microtip and external water pressure transducers

2005 ◽  
Vol 17 (4) ◽  
pp. 400-406 ◽  
Author(s):  
Andrew F. Hundley ◽  
Morton B. Brown ◽  
Linda Brubaker ◽  
Geoffrey W. Cundiff ◽  
Karl Kreder ◽  
...  
Keyword(s):  
Water Pressure ◽  
Pressure Transducers ◽  
External Water Pressure ◽  
External Water
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