Transient response of stiffened composite submersible hull to underwater explosion bubble

2015 ◽  
Vol 122 ◽  
pp. 229-238 ◽  
Author(s):  
S.W. Gong ◽  
B.C. Khoo
Keyword(s):  
Transient Response ◽  
Underwater Explosion

The Transient Response of Imperfect Thin-Walled Stiffened Cylindrical Shell Exposed to Side-On Underwater Explosion

2009 ◽  
Author(s):  
Ching-Yu Hsu ◽  
Chan-Yung Jen
Keyword(s):  
Cylindrical Shell ◽  
Transient Response ◽  
Cylindrical Shells ◽  
Underwater Explosion ◽  
Stiffened Cylindrical Shell ◽  
Analysis And Design ◽  
Finite Element Software ◽  
Pressure Load ◽  
Thin Walled ◽  
Stiffened Cylindrical Shells

The thin-walled stiffened cylindrical shells are usually applied in a submarine which takes the external pressure load, or in a boiler, pressure vessel or pipeline system which takes the internal pressure load. The thin-walled stiffened cylindrical shells under hydrodynamic loading are very sensitive to geometrical imperfections. This study is investigating an imperfect thin-walled stiffened cylindrical shell (out-of-round ratio is ψ = 2%) at a depth of 50m below the water level to see how it withstands sideward TNT 782 kg underwater explosion loading so as to understand its structural transient response. ABAQUS finite element software is used as an analysis tool in the current study, meanwhile, during the analysis process, the Fluid-Structure Interaction (FSI) condition is employed. The structural transient response results of stress and displacement time history of the imperfect thin-walled stiffened cylindrical shell can be used as a reference for the anti-underwater explosion analysis and design of future submersible vehicles, pressure hulls or related structural designs.

Transient Response of Coated Submersible Hull to Deep Underwater Explosion

2016 ◽  
Author(s):  
Caiyu Yin ◽  
Zeyu Jin ◽  
Yong Chen ◽  
Hongxing Hua
Keyword(s):  
Transient Response ◽  
Underwater Explosion ◽  
The Finite Element Method ◽  
Acceleration Response ◽  
One Dimensional ◽  
Combined Loads ◽  
Shock Mitigation ◽  
Deformation Velocity ◽  
Underwater Shock ◽  
Shock Resistance

Underwater explosion (UNDEX) can severely damage warships and submarines, so improving shock resistance ability of such weapons is of great importance. However, studies on enhancing shock resistance ability of submerged structures are limited. In this paper, the shock mitigation effects of cellular cladding coated on the submersible hull subjected to combined loads of hydrostatic pressure and shock wave are analyzed. First, one-dimensional analytical model is proposed to reveal the shock mitigation mechanism of cellular claddings. The pressure at fluid-structure interface and the thickness of cellular foam needed to fully dissipate shock energy are obtained. Then, the finite element method is employed to investigate the transient response of bare/coated submersible hull subjected to UNDEX. The results indicate that the cellular cladding coated on the pressure hull is very effective on reducing hull deformation, velocity and acceleration response if the cladding is not fully densified. Otherwise, the stress enhancement appears when the cladding is fully densified prematurely, which will weaken the shock mitigation effects. The research results are useful in designing surface shields for submersible hull so as to enhance its resistance to underwater shock damage.

Finite Element Analysis of Subsea Pipelines Subjected to Underwater Explosion

2013 ◽  
Author(s):  
F. Van den Abeele ◽  
P. Verleysen
Keyword(s):  
Shock Wave ◽  
Finite Element ◽  
Transient Response ◽  
Acoustic Pressure ◽  
Underwater Explosion ◽  
Structural Response ◽  
Added Mass ◽  
Radiation Damping ◽  
Time Response ◽  
Subsea Pipelines

Underwater mines and explosives, left in ports and harbours after World War II, can still pose a threat to subsea pipelines. In case of an accidental explosion, or even during controlled detonation, such explosives can cause significant damage to subsea pipelines. To assess the safety of pipelines exposed to an underwater explosion, finite element analyses are performed to predict the transient response of the pipeline to an acoustic pressure shock wave. This type of problem is characterized by a strong coupling between the structural response of the pipe and the acoustic pressure on the wetted interface between the pipe surface and the surrounding seawater. The spherical pressure wave induced by an underwater explosion is characterized by a very steep wave front, where the maximum pressure is attained over an extremely short rise time. The pressure then drops off exponentially over a significantly longer period of time. As a result, the structural behaviour is a combination of a long time response, dominated by an added mass effect (low frequency), a short time response, governed by radiation damping (high frequency), and an intermediate time-frequency response, where both added mass and radiation damping effects are present. In this paper, a finite element model is presented to simulate the transient response of a subsea pipeline subjected to an underwater explosion. The close coupling between acoustic pressure and structural response gives rise to numerical challenges like the accurate formulation and representation of the shock wave, the mesh requirements for the acoustic domain, and the position of the surface based absorbing radiation boundaries. An explicit dynamic solver is used to tackle these challenges, and to predict the behaviour of subsea pipelines exposed to an underwater explosion. The numerical results are compared to published experimental data, and can be used to assess the safety of submerged pipelines in the vicinity of explosives.

Separable cortico-basal ganglia networks support self-imposed transient response inhibition

2012 ◽  
Vol 43 (01) ◽  
Author(s):  
A Franz ◽  
O Granert ◽  
M Rijntjes ◽  
HR Siebner ◽  
C Weiller ◽  
...  
Keyword(s):  
Basal Ganglia ◽  
Transient Response ◽  
Response Inhibition

Transient Response of Electrostatic Field due to Collision ESD between Spherical Electrodes by using Bare-chip Optical Electric Field Sensor

2020 ◽  
Vol 140 (12) ◽  
pp. 599-600
Author(s):  
Kento Kato ◽  
Ken Kawamata ◽  
Shinobu Ishigami ◽  
Ryuji Osawa ◽  
Takeshi Ishida ◽  
...  
Keyword(s):  
Electric Field ◽  
Transient Response ◽  
Electrostatic Field ◽  
Electric Field Sensor ◽  
Field Sensor

Characteristic Analysis of a Micro DC-DC Converter for Portable Electronic Devices and an Improvement of Transient Response Characteristic

2008 ◽  
Vol 128 (12) ◽  
pp. 1373-1380
Author(s):  
Satoshi Sugahara ◽  
Kouhei Yamada ◽  
Haruhiko Nishio ◽  
Masaharu Edo ◽  
Toshiro Sato ◽  
...  
Keyword(s):  
Transient Response ◽  
Electronic Devices ◽  
Response Characteristic ◽  
Characteristic Analysis
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