scholarly journals Pressure Measurements on a Deforming Surface in Response to an Underwater Explosion in a Water-Filled Aluminum Tube

2001 ◽  
Vol 8 (1) ◽  
pp. 1-7 ◽  
Author(s):  
G. Chambers ◽  
H. Sandusky ◽  
F. Zerilli ◽  
K. Rye ◽  
R. Tussing ◽  
...  
Keyword(s):  
Shock Loading ◽  
Tube Wall ◽  
Underwater Explosion ◽  
Computer Code ◽  
Dynamic Interaction ◽  
Hypodermic Needle ◽  
Pressure Measurements ◽  
Cylindrical Structures ◽  
Explosive Charges ◽  
Carbon Resistor

Experiments have been conducted to benchmark DYSMAS computer code calculations for the dynamic interaction of water with cylindrical structures. Small explosive charges were suspended using hypodermic needle tubing inside Al tubes filled with distilled water. Pressures were measured during shock loading by tourmaline crystal, carbon resistor and ytterbium foil gages bonded to the tube using a variety of adhesives. Comparable calculated and measured pressures were obtained for the explosive charges used, with some gages surviving long enough to record results after cavitation with the tube wall.

scholarly journals Dynamic Measurements of Plastic Deformation in a Water-Filled Aluminum Tube in Response to Detonation of a Small Explosives Charge

1999 ◽  
Vol 6 (3) ◽  
pp. 125-132 ◽  
Author(s):  
Harold Sandusky ◽  
Paul Chambers ◽  
Frank Zerilli ◽  
Larry Fabini ◽  
William Gottwald
Keyword(s):  
Tube Wall ◽  
Residual Deformation ◽  
Computer Code ◽  
Dynamic Interaction ◽  
Distilled Water ◽  
Dynamic Measurements ◽  
Dynamic Data ◽  
Plastic Sheet ◽  
Thin Plastic ◽  
Displacement Measurements

Experiments have been conducted to benchmark computer code calculations for the dynamic interaction of explosions in water with structures. Aluminum cylinders with a length slightly more than twice their diameter were oriented vertically, sealed on the bottom by a thin plastic sheet, and filled with distilled water. An explosive charge suspended in the center of the tube plastically deformed but did not rupture the wall. Tube wall velocity, displacement, and strain were directly measured. The agreement among the three sets of dynamic data and the agreement of the terminal displacement measurements with the residual deformation were excellent.

The Influence of Piping Arrangement on the Response of Vibration Isolation System Under Underwater Explosion Loading

2019 ◽  
Author(s):  
Chen Pan ◽  
Wei Qiang ◽  
Liu Zhizhong ◽  
Wang Guan
Keyword(s):  
Shock Loading ◽  
Vibration Isolation ◽  
Underwater Explosion ◽  
Mechanical Equipment ◽  
Piping System ◽  
Flexible Pipe ◽  
Isolation System ◽  
Floating Raft ◽  
Shock Resistance ◽  
Actual Response

Abstract The response of ship equipment under non-contact underwater explosion shock loading was one of the main loadings of equipment. In order to cut down mechanical noise caused by mechanical equipment, vibration isolation measures, such as floating raft, vibration isolation, were widely used on noise mechanical equipments in acoustical stealth of ship, vibration isolation can reduce the vibration transfer to install base effectively, while the anti-shock resistance of vibration isolation and the equipment was important synchronously, as for the response of the equipment on vibration isolation, especially the actual response of the vibration isolation with piping system under shock loading. In this paper, the research on the response of vibration isolation, equipment, flexible piping and piping under underwater explosion shock loading were considered together, and the response of vibration isolation under shock load was analyzed with different piping arrangement. Found that the piping system has a significant impact on the response of the equipment under horizontal impact, but almost all equipments were assessed in experiment without considering the piping system. With the precondition of the effect of vibration isolation, a more rigid flexible pipe can be taken was benefit to the anti-shock resistance of vibration isolation.

Correlation of Support Impact Force and Fretting-Wear for a Heat Exchanger Tube

1984 ◽  
Vol 106 (1) ◽  
pp. 69-77 ◽  
Author(s):  
P. L. Ko ◽  
H. Basista
Keyword(s):  
Heat Exchanger ◽  
Impact Force ◽  
Computer Code ◽  
Oblique Impact ◽  
Dynamic Interaction ◽  
Fretting Wear ◽  
Heat Exchanger Tube ◽  
Dynamic Interactions ◽  
Realistic Assessment ◽  
Exchanger Tube

Flow-induced tube vibration can cause dynamic interactions between a tube and its supports. Both wear information and results from vibration analyses are needed to achieve a realistic assessment of long-term tube wear. Normal and oblique impact forces at the tube supports characterize dynamic interaction between tube and tube-support, and can be correlated to the rate of fretting-wear. A statistical analysis of the force signal provides an indication of the time distribution of various force levels during a vibration cycle. Different schemes for obtaining a weighted sum of these force levels were developed to account for changes in excitation levels, tube/support clearance, and the type of tube motion. With one of the schemes, the correlation to measured wear data was good. Therefore, fretting-wear can be estimated directly from the analytically predicted support impact force in a steam generator or heat exchanger tube. The effects of other support parameters, such as tube support land area, can be added to the empirical equation. A series of tests involving the three parameters mentioned were performed in room temperature water. Forces along two orthogonal axes at the support were recorded and analysed. The paper presents the results of these tests and shows the correlation between the wear results and the force functions. A computer code for predicting tube/support dynamic interaction is used to estimate wear damages from the experimental force-wear correlation.

Simulation of Responses of Liquid Filled Double Bottom Structures Subjected to a Closely Underwater Explosion Shock Loading

2011 ◽  
Vol 88-89 ◽  
pp. 662-667 ◽  
Author(s):  
Ting Tang ◽  
Li Jun Wang ◽  
Jin Bo Ma
Keyword(s):  
Finite Element ◽  
Shock Loading ◽  
Underwater Explosion ◽  
Finite Element Program ◽  
Explicit Finite Element ◽  
Comparative Analyses ◽  
Element Program ◽  
The Difference ◽  
Bottom Structures

The purpose of this work is to study the effect of liquid in double bottom structures subjected to a closely underwater explosion shock loading. The comparative analyses are made by use of a commercial, explicit finite element program. Based on the difference of depth of liquid in double bottom structures and distance between explosive and outer bottom, six cases were simulated in this paper. The results show that liquid in cabins can enhance the resistance of double bottom structures to an underwater explosion.

On the Dynamic Collapse of Cylindrical Shells Under Impulsive Pressure Loadings

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Luciana Loureiro da Silva Monteiro ◽  
Theodoro Antoun Netto ◽  
Paulo Cesar da Camara Monteiro
Keyword(s):  
Cylindrical Shells ◽  
Underwater Explosion ◽  
Acoustic Medium ◽  
Isotropic Hardening ◽  
Water Tank ◽  
Numerical Work ◽  
Collapse Pressure ◽  
Explosion Pressure ◽  
Explosive Charges ◽  
Impulsive Pressure

The dynamic collapse of submerged cylindrical shells subjected to lateral impulsive pressure loads caused by underwater explosions is studied via coupled experimental and numerical work. Two sets of experiments were performed. Initially, 50.8 mm outside diameter aluminum tubes with diameter-to-thickness ratio of 32.3 were tested inside a pressure vessel. Hydrostatic pressure was applied quasi-statically up to the onset of collapse in order to obtain the collapse pressure of the tubes tested. Subsequently, similar tubes were tested in a 5 m × 5 m × 1.6 m deep water tank under various explosive charges placed at different distances. Explosive charges and standoff distances were combined so as to eventually cause collapse of the specimens. Dynamic pressures were recorded using a fit-for-purpose data acquisition system with sampling rates of up to 1 mega samples/s/channel. In parallel, finite element models were developed using commercially available software to simulate underwater explosion, pressure wave propagation, its interaction with a cylindrical shell, and the subsequent onset of dynamic collapse. The surrounding fluid was modeled as an acoustic medium, the shells as J2 flow theory based materials with isotropic hardening, and proper fluid–structure interaction elements accounting for relatively small displacements of the boundary between fluid and structure were used. Subsequently, the physical explosion experiments were numerically reproduced with good correlation between results. Finally, a parametric study was carried out to examine the effect on the pipe under different impulsive pressure loads.

Basic Study on the Crushing of Frozen Soil by Shock Loading

2007 ◽  
Author(s):  
Toshiaki Watanabe ◽  
Hironori Maehara ◽  
Masahiko Otsuka ◽  
Shigeru Itoh
Keyword(s):  
Shock Wave ◽  
High Speed ◽  
Shock Loading ◽  
Underwater Explosion ◽  
Frozen Soil ◽  
High Speed Camera ◽  
Underwater Shock Wave ◽  
Basic Study ◽  
Underwater Shock ◽  
A New Technique

The aim of study is to confirm a new technique that can crush the frozen soil and/or ice block using underwater shock wave generated by the underwater explosion of explosive. This technique can lead to the earlier sowing, which can have the larger harvest because the duration of sunshine increases. Especially, in Hokkaido prefecture, Japan, if the sowing is carried out in April, we can expect to have 150% of harvest in the ordinary season. This technique is effective against the cold regions. For example, Korea, China, Mongolia, Russia, Norway, and Sweden, etc. At first, we carried out experiments usung a detonating fuse and ice block. The process of ice breaking was observed by means of a high-speed camera. In order to check about that influence we tried to give an actual frozen soil a shock wave.

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