Transient Response of Submerged Plates Subject to Underwater Shock Loading: An Analytical Perspective

2008 ◽  
Vol 75 (4) ◽  
Author(s):  
Zhanke Liu ◽  
Yin L. Young
Keyword(s):  
Structural Dynamics ◽  
Transient Response ◽  
Shock Loading ◽  
Structural Response ◽  
Small Range ◽  
Pressure Loading ◽  
Structure Interaction ◽  
Shock Response ◽  
Analytical Perspective ◽  
Underwater Shock

In this paper, Taylor’s floating air-backed plate (ABP) model is extended to the case of a submerged water-backed plate (WBP) within the acoustic range. The solution of the WBP is cast into the same format as that of the ABP with a modified fluid-structure interaction (FSI) parameter, which allows a unified analysis of the ABP and WBP using the same set of formulas. The influence of back conditions on fluid and structural dynamics, including fluid cavitation, is systematically investigated. Asymptotic limits are mathematically identified and physically interpolated. Results show that the WBP experiences lower equivalent pressure loading, reduced structural response, and hence lower peak momentum gaining. The time to reach peak momentum is shorter for the WBP than for the ABP. Cavitation is found to be almost inevitable for the ABP, while relevant to the WBP only for a small range of the FSI parameter. Implications to shock response of submerged structures are briefly discussed.

Analytical Determination of Shock Response Spectra for an Impulse-Loaded Proportionally Damped System

Volume 1 ◽  
2004 ◽  
Author(s):  
R. David Hampton ◽  
Nathan S. Wiedenman ◽  
Ting H. Li
Keyword(s):  
Transient Response ◽  
Shock Loading ◽  
Response Spectrum ◽  
Response Spectra ◽  
Analytical Determination ◽  
System Response ◽  
Mechanical Shock ◽  
Shock Response ◽  
Mass Spring ◽  
The Impact

Many military systems must be capable of sustained operation in the face of mechanical shocks due to projectile or other impacts. The most widely used method of quantifying a system’s vibratory transient response to shock loading is called the shock response spectrum (SRS). The system response for which the SRS is to be determined can be due, physically, either to a collocated or to a noncollocated shock loading. Taking into account both possibilities, one can define the SRS as follows: the SRS presents graphically the maximum transient response (output) of an imaginary ideal mass-spring-damper system at one point on a flexible structure, to a particular mechanical shock (input) applied to an arbitrary (perhaps noncollocated) point on the structure, as a function of the natural frequency of the imaginary mass-spring-damper system. For a response point sufficiently distant from the impact area, many Army platforms (such as vehicles) can be accurately treated as linear systems with proportional damping. In such cases the output due to an impulsive mechanical-shock input can be decomposed into exponentially decaying sinusoidal components, using normal-mode orthogonalization. Given a shock-induced loading comprising such components, this paper provides analytical expressions for the various common SRS forms. The analytical approach to SRS-determination can serve as a verification of, or an alternative to, the numerical approaches in current use for such systems. No numerical convolution is required, because the convolution integrals have already been accomplished analytically (and exactly), with the results incorporated into the algebraic expressions for the respective SRS forms.

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.

Probabilistic Risk Prediction of Submarine Pipelines Subjected to Underwater Explosion Shock

1999 ◽  
Vol 121 (4) ◽  
pp. 251-254 ◽  
Author(s):  
Z. Zong ◽  
K. Y. Lam ◽  
G. R. Liu
Keyword(s):  
Shock Loading ◽  
Simple Procedure ◽  
Underwater Explosion ◽  
Coupling Model ◽  
Oil Pipeline ◽  
Structure Interaction ◽  
The Monte Carlo Method ◽  
Underwater Shock ◽  
Interaction Problem ◽  
Failure Probabilities

A simple procedure is proposed in this paper to estimate the global failure probabilities of a submarine oil pipeline subjected to underwater explosion shock wave. The deterministic response of a pipeline subjected to an underwater shock loading is first given by solving a simplified fluid-structure interaction problem. Compared with an FEM/BEM coupling model, the present method gives good results at much lower computational efforts. Then, the Monte Carlo method is used to find the global failure probabilities of the pipeline. Finally, a practical example is given.

Fluid–Structure Interaction of High Aspect-Ratio Hair-Like Micro-Structures Through Dimensional Transformation Using Lattice Boltzmann Method

2016 ◽  
Vol 08 (08) ◽  
pp. 1650095 ◽  
Author(s):  
H. Devaraj ◽  
Kean C. Aw ◽  
E. Haemmerle ◽  
R. Sharma
Keyword(s):  
Fluid Flow ◽  
Drag Force ◽  
Lattice Boltzmann ◽  
Stokes Equations ◽  
Fluid Structure Interaction ◽  
Structural Response ◽  
Momentum Exchange ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Micro Structures

3D printed hair-like micro-structures have been previously demonstrated in a novel micro-fluidic flow sensor aimed at sensing air flows down to rates of a few milliliters per second. However, there is a lack of in-depth understanding of the structural response of these ‘micro-hairs' under a fluid flow field. This paper demonstrates the use of lattice Boltzmann methods (LBM) to understand this structural response towards a better optimization of the micro-hair flow sensors designed to suit the end applications' needs. The LBM approach was chosen as an efficient alternative to simulate Navier–Stokes equations for modeling fluid flow around complex geometries primarily for improved accuracy and simplicity with lesser computational costs. As the spatial dimensions of the sensor's flow channel are much larger in comparison to the actual micro-hairs (the sensing element), a multidimensional approach of combining two-dimensional (D2Q9) and three-dimensional (D3Q19) lattice configurations were implemented for improved computational speeds and efficiency. The drag force on the micro-hairs was estimated using the momentum-exchange method in the D3Q19 configuration and this drag force is transferred to the structural analysis model which determines the micro-hair deformation using Euler–Bernoulli beam theory. The entirety of the LBM Fluid–Structure Interaction (FSI) model was implemented within MATLAB and the obtained results are compared against the numerical model implemented on a commercially available software package.

Transient response of structures with uncertain properties to nonlinear shock loading

2013 ◽  
Vol 332 (22) ◽  
pp. 5821-5836 ◽  
Author(s):  
Mauro Caresta ◽  
Robin S. Langley ◽  
Jim Woodhouse
Keyword(s):  
Transient Response ◽  
Shock Loading ◽  
Nonlinear Shock

The Program DYSMAS/ELC and its Application on Underwater Shock Loading of Vessels

1985 ◽  
pp. 280-290
Author(s):  
W. Bergerhoff ◽  
W. Mohr ◽  
W. Pfrang ◽  
F. Scharpf
Keyword(s):  
Shock Loading ◽  
Underwater Shock
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