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Study on anti-explosion performance of double-layer structures subjected to far-field underwater explosion
Published in J. Parunov, C. Guedes Soares, Trends in the Analysis and Design of Marine Structures, 2019
The components of underwater explosion load are diverse and the physical phenomena are complex, including the detonation of the initial explosive, the formation and propagation of the shock wave, the cavitation caused by the interaction between the shock wave and the free surface or structure, the expansion, contraction and uplift of the bubbles, and the water jet formed by the bubble collapse. Among them, the shock wave and bubble pulsation pressure are considered as the two main loads for the far-field underwater explosion (Xin et al. 2017).
A simplified method to assess the damage of an immersed cylinder subjected to underwater explosion
Published in C. Guedes Soares, Y. Garbatov, Progress in the Analysis and Design of Marine Structures, 2017
K. Brochard, H. Le Sourne, G. Barras
The loading due to the underwater explosion shock wave is supposed to be severe enough so that the shell deforms plastically. As a result, the shell undergoes radial deflection w(x, θ, t), where x, θ denotes the axial and circumferential coordinates respectively and t denotes time.
A peak-over-threshold approach for the numerical modeling of 26 December 2004 Indian Ocean Tsunami at the Kalpakkam coast, Tamil Nadu, India
Published in ISH Journal of Hydraulic Engineering, 2020
Denesh J. Herrick, Mohit Sharma, Prasad K. Bhaskaran, Neeraj K. Goyal
The term tsunami, also known as a seismic sea wave is derived from the Japanese word meaning ‘harbor wave’. It is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions, and other underwater explosions (including detonations of underwater nuclear devices), landslides, glacier, calvings, meteorite impacts and other disturbances above or below the water all have the potential to generate a tsunami. Once generated by the displacement of water, a tsunami contrasts itself both with a normal ocean wave generated by wind and with tides generated by the gravitational force of astronomical bodies on the water surface. Often originally called as tidal waves, the phenomenon has little to do with tides and the term refers to waves that have a characteristic long wavelength. In general they are referred in literature as ‘long waves’ created by the sudden displacement of water surface. In perspective of geological time scales, tsunami can be considered as low-frequency, high-magnitude events.
Numerical modelling of tsunami in the Makran Subduction Zone – A case study on the 1945 event
Published in Journal of Operational Oceanography, 2019
A tsunami (also known as a seismic sea wave) is a series of water waves (similar to shallow water waves) in a water body caused by the abrupt displacement of a large volume of water initially resembling a rapidly rising tide. A tsunami can be generated by underwater earthquakes, landslides, fault breaks (ruptures), volcanic eruptions and other underwater explosions (such as the detonation of nuclear devices), glacier calving, impact of objects from outer space (such as meteorites, asteroids, comets) and other disturbances in water. Ninety percent or more of historical tsunamis in the world have been generated by earthquakes in the sea and coastal regions. Generally larger and shallower hypocentre earthquakes cause larger tsunamis (PIANC 2010).
Parametric study for underwater blast-induced pipeline response embedded in marine sediments
Published in Marine Georesources & Geotechnology, 2019
C. C. Liao, Yaguang Wang, Jinjian Chen, Qi Zhang
Submerged pipelines are installed extensively with great development of the offshore oil industry, which may be threatened by unexploded mines left during the past wars. A quantity of energy is released as underwater explosion takes place. A superheated, highly compressed gas bubble and stimulated shock wave are generated in the detonation zone. And the overpressure is up to 5 GPa (Rajendran and Narasimhan 2006). Blast energy produced by underwater explosion will propagate in seawater and seabed simultaneously. Meanwhile, submerged pipelines are installed in the marine environment with various embedment depth. It is not accurate to neglect interaction of pipeline–soil as has been mentioned in the introduction. Moreover, soil is considered as a multiphase material, including air, pore water, and soil particle. Propagation of blast wave in the porous media is affected by saturation degree significantly (Wang, Lu, and Hao 2004). Blast energy attenuates slowest in the fully saturated soil (Leong et al. 2007; Yankelevsky, Karinski, and Feldgun 2011). Accordingly, seabed is treated as fully saturated soil in this study. Biot (1956) originally proposed the theory of wave propagation in saturated porous media taking inertia of soil skeleton and pore fluid into account. The u–p dynamic form derived by Zienkiewicz, Chang, and Bettess (1980) is adopted to calculate pore water effect in marine sediment considering difficulty of solving Biot’s equations. The equilibriums of porous medium, equilibriums of fluid phrase and the mass conservation of fluid phase are expressed as follow: where is total stress which is sum of effective stress acting on the soil skeleton and pore water pressure p. is body force acceleration, is displacement of the soil skeleton, is the average fluid phase displacement, and n is porosity of soil material. is bulk modulus of pore fluid. and ρ represent pore fluid density and soil density, respectively. It could be written as in which is density of the soil skeleton.