Global ETD Search
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Showing 1 to 14 of 14 for “"UNDEX"”.
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Numerical Study of Energy Loss Mechanisms in Oscillating Underwater Explosion (UNDEX) Bubbles
… was investigated for underwater explosion (UNDEX) events. The problem of over-prediction for long-term UNDEX bubble behavior in modern hydrocodes that is known to be due to neglected secondary energy-loss mechanisms is evaluated. A single secondary energy-loss mechanism is established as the …
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Modeling Underwater Explosion (UNDEX) Shock Effects for Vulnerability Assessment in Early Stage Ship Design
This thesis describes and assesses a simplified tool for modeling underwater explosion shock effects during early naval ship concept design. A simplified fluid model using Taylor flat-plate theory is incorporated directly into the OpenFSI module code in Nastran and used to interface with the …
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Development of a Lung Surrogate Model for Assessing Biomechanical Responses to Underwater Explosions (UNDEX)
Underwater explosions (UNDEX) generate high-energy shock waves that pose significant risks to military personnel during training exercises and combat scenarios. The primary objective of this research is to develop a surrogate modeling framework using engineering materials to investigate the …
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A Hybrid Framework of CFD Numerical Methods and its Application to the Simulation of Underwater Explosions
Underwater explosions (UNDEX) and a ship's vulnerability to them are problems of interest in early-stage ship design. A series of events occur sequentially in an UNDEX scenario in both the fluid and structural domains and these events happen over a wide range of time and spatial scales. Because of …
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A Runge Kutta Discontinuous Galerkin-Direct Ghost Fluid (RKDG-DGF) Method to Near-field Early-time Underwater Explosion (UNDEX) Simulations
… simulating a near-field underwater explosion (UNDEX). An UNDEX consists of a complicated sequence of events over a wide range of time scales. Due to the complex physics, separate simulations for near/far-field and early/late-time are common in practice. This work focuses on near-field …
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An Underwater Explosion-Induced Ship Whipping Analysis Method for use in Early-Stage Ship Design
… of a hull girder to underwater explosion (UNDEX) bubble pulse loading. A potential flow-based UNDEX bubble model capable of calculating the behavior of a migrating bubble for up to three pulses is developed. An approximate vertical plane ship vibration model is derived using fundamental …
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Finite and Spectral Element Methods for Modeling Far-Field Underwater Explosion Effects on Ships
The far-field underwater explosion (UNDEX) problem is a complicated problem dominated by two phenomena: the shock wave traveling through the fluid and the cavitation in the fluid. Both of these phenomena have a significant effect on the loading of ship structures subjected to UNDEX. An approach to …
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Computationally-effective Modeling of Far-field Underwater Explosion for Early-stage Surface Ship Design
… a ship to the impact of underwater explosions (UNDEX) and how to incorporate this factor into early-stage ship design is an important aspect in the ship survivability study. In this dissertation, attention is focused on the cost-efficient simulation of the ship response to a far-field UNDEX …
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Assessment of LS-DYNA and Underwater Shock Analysis (USA) Tools for Modeling Far-Field Underwater Explosion Effects on Ships
… general far-field underwater explosions (UNDEX) by modeling a three-dimensional box barge that is subjected to a far-field underwater explosion. Past UNDEX models using these tools have not been validated by experiment and most are limited to very specific problems because of the …
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Exploring Immersed FEM, Material Design, and Biological Tissue Material Modeling
… of lung tissue for Diver Underwater Explosion (UNDEX) simulations. In the first part, a shape optimization scheme utilizing a four-noded rectangular immersed-interface element is presented. This method eliminates the need for interface fitted mesh or mesh morphing, reducing computational costs …
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Regionalism in South East Asia: a factor analysis approach
… from a variety of secondary sources including UNDEX United Nations documents, International Trade Directory and the World Handbook of Political and Social Indicators. The variables were then correlated to check the extent of regionalism in the ASEAN countries. Factor Analysis and Pearson's …
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Present position of spinal analgesia
… and lives which would undoubtedly have been lost undex* a General Anaesthetic, have been saved by its means. But as in the introduction of all important Surgical procedures, the evolution has been slow. One authority gives a glowing account of the virtues Spinal Analgesia whereas another points …
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Investigation of Close Proximity Underwater Explosion Effects on a Ship-Like Structure Using the Multi-Material Arbitrary Lagrangian Eulerian Finite Element Method
This thesis investigates the characteristics of a close proximity underwater explosion and its effect on a ship-like structure. Finite element model tests are conducted to verify and validate the propagation of a pressure wave generated by an underwater explosion through a fluid medium, and the …