Analytical Modeling of the Underwater Shock Response of Rigid and Elastic Plates Near a Solid Boundary

2013 ◽  
Vol 80 (2) ◽  
Author(s):  
Qinyuan Li ◽  
Michail Manolidis ◽  
Yin L. Young
Keyword(s):  
Rise Time ◽  
Shock Loading ◽  
Fluid Structure Interaction ◽  
Damping Coefficient ◽  
Solid Boundary ◽  
Material Damping ◽  
Fluid Structure ◽  
Fixed Boundary ◽  
Structure Interaction ◽  
Underwater Shock

In this paper, analytical solutions are derived for the case when an elastic water-backed plate (WBP) is subject to an exponential shock loading near a fixed solid boundary. Two cases, a rigid plate and an elastic plate represented by two mass elements connected by a spring and a dashpot, are studied. The analytical solution is extended from Taylor's (1963, “The Pressure and Impulse of Submarine Explosion Waves on Plates,” Scientific Papers of Sir Geoffrey Ingram Taylor, Vol. 3, G. K. Batchelor, ed., Cambridge University Press, Cambridge, UK, pp. 287–303) floating air-backed plate (ABP) model and the water-backed plate model of Liu and Young (2008, “Transient Response of Submerged Plates Subject to Underwater Shock Loading: An Analytical Perspective,” J. Appl. Mech., 75(4), 044504; 2010, “Shock-Structure Interaction Considering Pressure Precursor,” Proceedings of the 28th Symposium on Naval Hydrodynamics, Pasadena, CA). The influences of five parameters are studied: (a) the distance of the fixed boundary from the back plate d, (b) the fluid structure interaction (FSI) parameter φ of the plate, (c) the stiffness of the plate as represented by the natural frequency of the system T, (d) the material damping coefficient CD of the plate, and (e) the pressure precursor (rise) time θr. The results show that the pressure responses at the front and back surfaces of the plate are greatly affected by the proximity to the fixed boundary, the fluid-structure interaction parameter, the ratio of the shock decay time to the natural period of the structure, and the rise time of incident pressure. The effect of structural damping (assuming a typical material damping coefficient of 5%) is found to be practically negligible compared to the other four parameters.

scholarly journals Validation of a Surrogate Model for Marine Mammal Lung Dynamics Under Underwater Explosive Impulse

2019 ◽  
Author(s):  
Emily L. Guzas ◽  
Stephen E. Turner ◽  
Matthew Babina ◽  
Brandon Casper ◽  
Thomas N. Fetherston ◽  
...  
Keyword(s):  
Test Data ◽  
Marine Mammal ◽  
Marine Mammals ◽  
Shock Loading ◽  
Fluid Structure Interaction ◽  
Mammal Species ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Underwater Environment ◽  
Lung Response

Abstract Primary blast injury (PBI), which relates gross blast-related trauma or traces of injury in air-filled tissues or those tissues adjacent to air-filled regions (rupture/lesions, contusions, hemorrhaging), has been documented in a number of marine mammal species after blast exposure [1, 2, 3]. However, very little is known about marine mammal susceptibility to PBI except in rare cases of opportunistic studies. As a result, traditional techniques rely on analyses using small-scale terrestrial mammals as surrogates for large-scale marine mammals. For an In-house Laboratory Independent Research (ILIR) project sponsored by the Office of Naval Research (ONR), researchers at the Naval Undersea Warfare Center, Division Newport (NUWCDIVNPT), have undertaken a broad 3-year effort to integrate computational fluid-structure interaction techniques with marine mammal anatomical structure. The intent is to numerically simulate the dynamic response of a marine mammal thoracic cavity and air-filled lungs to shock loading, to enhance understanding of marine mammal lungs to shock loading in the underwater environment. In the absence of appropriate test data from live marine mammals, a crucial part of this work involves code validation to test data for a suitable surrogate test problem. This research employs a surrogate of an air-filled spherical membrane structure subjected to shock loading as a first order approximation to understanding marine mammal lung response to underwater explosions (UNDEX). This approach incrementally improves upon the currently used one-dimensional spherical air bubble approximation to marine mammal lung response by providing an encapsulating boundary for the air. The encapsulating structure is membranous, with minimal simplified representation not accounting for marine mammal species-specific and individual animal differences in tissue composition, rib mechanics, and mechanical properties of interior lung tissue. NUWCDIVNPT partnered with the Naval Submarine Medical Research Laboratory (NSMRL) to design and execute a set of experiments to investigate the shock response of an air-filled rubber dodgeball in a shallow underwater environment. These tests took place in the 2.13 m (7-ft) diameter pressure tank at the University of Rhode Island, with test measurements including pressure data and digital image correlation (DIC) data captured with high-speed cameras in a stereo setup. The authors developed 3-dimensional computational models of the dodgeball experiments using Dynamic System Mechanics Advanced Simulation (DYSMAS), a Navy fluid-structure interaction code. DYSMAS models of a variety of different problems involving submerged pressure vessel structures responding to hydrostatic and/or UNDEX loading have been validated against test data [4]. Proper validation of fluid structure interaction simulations is quite challenging, requiring measurements in both the fluid and structure domains. This paper details the development of metrics for comparison between test measurements and simulation results, with a discussion of potential sources of uncertainty.

Study and Analysis of the Fluid-Structure Interaction Between Apple and Underwater Shock Wave

2007 ◽  
Author(s):  
Asuka Oda ◽  
Moji Moatamedi ◽  
Shigeru Itoh
Keyword(s):  
Shock Wave ◽  
Apple Juice ◽  
Fluid Structure Interaction ◽  
Water Tank ◽  
Underwater Shock Wave ◽  
Element Analysis ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Exploratory Experiment ◽  
Underwater Shock

Shock wave treatment of an apple can produce a soft apple similar to a sponge containing water. Therefore, without needing to cut and grate apples, apple juice can be easily obtained by squeezing by hand. In a previous result, it was reported that more than 40MPa shock pressure was needed to make a soft apple. From observation for the shock treatment for the apple, an oblique wave was produced from a detonating fuse and the wave reflected at the surface of the apple. The resulting shock wave data was obtained. In the result of further observations, there was the possibility that the wave passing through the apple was attenuated faster than the wave passing through water. In this report, the same method in the previous research was used. Apples, detonating fuse, and electric detonator were set in water tank, with the fuse initiated by electric detonator. In this research, the behavior of shock wave passing through an apple was researched as exploratory experiment for numerical analysis. In the future, we want to attempt to analyze the fluid-structure interaction between the apple and underwater shock wave by using computer finite element analysis.

Fluid–Structure Interaction Effects in the Dynamic Response of Free-Standing Plates to Uniform Shock Loading

2006 ◽  
Vol 74 (5) ◽  
pp. 1042-1045 ◽  
Author(s):  
Nayden Kambouchev ◽  
Raul Radovitzky ◽  
Ludovic Noels
Keyword(s):  
Dynamic Response ◽  
Shock Intensity ◽  
Acoustic Waves ◽  
Shock Loading ◽  
Fluid Structure Interaction ◽  
Mass Range ◽  
Free Standing ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Transmitted Impulse

The problem of uniform shocks interacting with free-standing plates is studied analytically and numerically for arbitrary shock intensity and plate mass. The analysis is of interest in the design and interpretation of fluid–structure interaction (FSI) experiments in shock tubes. In contrast to previous work corresponding to the case of incident blast profiles of exponential distribution, all asymptotic limits obtained here are exact. The contributions include the extension of Taylor’s FSI analysis for acoustic waves, the exact analysis of the asymptotic limits of very heavy and very light plates for arbitrary shock intensity, and a general formula for the transmitted impulse in the intermediate plate mass range. One of the implications is that the impulse transmitted to the plate can be expressed univocally in terms of a single nondimensional compressible FSI parameter.

An underwater shock simulator

2006 ◽  
Vol 462 (2067) ◽  
pp. 1021-1041 ◽  
Author(s):  
V.S Deshpande ◽  
A Heaver ◽  
N.A Fleck
Keyword(s):  
Finite Element ◽  
Fluid Structure Interaction ◽  
Element Analysis ◽  
Compression Phase ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Decay Times ◽  
Underwater Shock ◽  
The One ◽  
Peak Pressures

An underwater shock simulator has been developed for the underwater shock loading of materials and test structures within the laboratory. The tube is struck at one end by a steel projectile, with the test structure placed at the opposite end of the tube. Realistic exponentially decaying pressure pulses are generated in the water with peak pressures in the range 15–70 MPa and decay times ranging from 0.1 to 1.5 ms. The peak pressure and the pulse duration are independently adjusted by varying the projectile velocity and mass, respectively. The underwater shock simulator is used to investigate the one-dimensional fluid–structure interaction of sandwich plates with steel face sheets and an aluminium foam core. The degree of core compression is measured as a function of both the underwater shock impulse and the Taylor fluid–structure interaction parameter. Fully coupled finite element simulations agree well with the measurements while decoupling the fluid–structure interaction phase from the core compression phase within the finite element analysis leads to an under-prediction of the degree of core compression.

scholarly journals An Immersed Boundary–Lattice Boltzmann Approach to Study Deformation and Fluid–Structure Interaction of Hollow Sealing Strip

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8110
Author(s):  
Zhe Shen ◽  
Zhigang Yang ◽  
Munawwar Ali Abbas ◽  
Haosheng Yu ◽  
Li Chen
Keyword(s):  
Flow Field ◽  
Lattice Boltzmann ◽  
Fluid Structure Interaction ◽  
Immersed Boundary ◽  
Solid Boundary ◽  
Specific Situation ◽  
Technical Problems ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Hyper Elastic

A combined immersed boundary–lattice Boltzmann approach is used to simulate the dynamics of the fluid–structure interaction of a hollow sealing strip under the action of pressure difference. Firstly, the multiple relaxation times LBM model, hyper-elastic material model and immersed boundary method were deduced. According to the strain characteristics of hyper-elastic materials and the specific situation of friction between the elastic boundary and solid boundary, the internal force and the external force on the immersed boundary were discussed and deduced, respectively. Then, a 2D calculation model of the actual hollow sealing strip system was established, during which technical problems such as the equivalent wall thickness of the sealing strip and the correction of the stiffness of the contact corner were solved. The reliability of the model was verified by comparing results of FEM simulation of quasi-static deformation. Following this, the simulation results of three typical cases of sealing strips were presented. The results show that when the sealing strip fails, there will be a strong coupling phenomenon between the flow field and the sealing strip, resulting in the oscillation of the flow field and the sealing strip at the same frequency.

scholarly journals Fluid-Structure Interaction Mechanisms for Close-In Explosions

2000 ◽  
Vol 7 (5) ◽  
pp. 265-275 ◽  
Author(s):  
Andrew B. Wardlaw Jr. ◽  
J. Alan Luton
Keyword(s):  
Flow Field ◽  
Rigid Body ◽  
Shock Loading ◽  
Fluid Structure Interaction ◽  
Pressure Level ◽  
Fluid Structure ◽  
Underwater Explosions ◽  
Structure Interaction ◽  
Bubble Interaction ◽  
Initial Shock

This paper examines fluid-structure interaction for close-in internal and external underwater explosions. The resulting flow field is impacted by the interaction between the reflected explosion shock and the explosion bubble. This shock reflects off the bubble as an expansion that reduces the pressure level between the bubble and the target, inducing cavitation and its subsequent collapse that reloads the target. Computational examples of several close-in interaction cases are presented to document the occurrence of these mechanisms. By comparing deformable and rigid body simulations, it is shown that cavitation collapse can occur solely from the shock-bubble interaction without the benefit of target deformation. Addition of a deforming target lowers the flow field pressure, facilitates cavitation and cavitation collapse, as well as reducing the impulse of the initial shock loading.

Coupled Fluid–Structure Interaction based Numerical Investigation on the Large Deformation Behavior of Thin Plates Subjected to under Water Explosion

2020 ◽  
Vol 12 (4) ◽  
Author(s):  
C. Suresh ◽  
K. Ramajeyathilagam
Keyword(s):  
Equation Of State ◽  
Numerical Investigation ◽  
Large Deformation ◽  
Shock Loading ◽  
Fluid Structure Interaction ◽  
Material Model ◽  
Loading Conditions ◽  
Test Plate ◽  
Fluid Structure ◽  
Structure Interaction

Coupled fluid structure interaction based numerical investigation on rectangular mild steel plates subjected to underwater explosion is tested using Explosion Bulge Testing (EBT) is presented in this paper. The test plate along with the EBT box model fixture immersed in water domain subjected to small explosive charges of PEK I at a standoff distance of 0.15 m from centre of the plate is considered for the analysis using LSDYNA code. For the analysis, explosive charge is modelled using high explosive burn with JWL equation of state. The fluid is using null material model with Gruinesian equation of state, the EBT setup is using Lagrangian solid element with rigid material model and the test plate is modelled using Belytschko-Tsay shell element with piece-wise linear plasticity material model. The numerical analysis aims to predict the permanent deformation of the plate under various shock loading conditions. The results are then compared with experimental results available in the literature and numerical results based on Taylor’s plate theory. Parametric investigations on the large deformation behaviour of different plate thickness of various shock loading conditions are presented.

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