Transient underwater shock response of sacrificed coating with continuous density graded foam core

2016 ◽  
Vol 98 ◽  
pp. 297-307 ◽  
Author(s):  
Y. Chen ◽  
F. Chen ◽  
W. Zhang ◽  
Z.P. Du ◽  
H.X. Hua
Keyword(s):  
Foam Core ◽  
Continuous Density ◽  
Shock Response ◽  
Underwater Shock

Dynamic Hydroelastic Scaling of the Underwater Shock Response of Composite Marine Structures

2011 ◽  
Vol 79 (1) ◽  
Author(s):  
Erin E. Bachynski ◽  
Michael R. Motley ◽  
Yin L. Young
Keyword(s):  
Underwater Explosion ◽  
Elastic Beam ◽  
Initial Response ◽  
Scaling Relations ◽  
Scaling Analysis ◽  
Marine Structures ◽  
Finite Element Software ◽  
Anisotropic Composite ◽  
Shock Response ◽  
Underwater Shock

The hydroelastic scaling relations for the shock response of water-backed, anisotropic composite marine structures are derived and verified. The scaling analysis considers the known underwater explosion physics, previously derived analytical solutions for the underwater shock response of a water-backed plate, and elastic beam behavior. To verify the scaling relations, the hydroelastic underwater shock response of an anisotropic composite plate at several different scales is modeled as a fully coupled fluid-structure interaction (FSI) problem using the commercial Lagrangian finite element software ABAQUS/Explicit. Following geometric and Mach similitude, as well as proper scaling of the FSI parameter, scaling relations for the structural natural frequencies, fluid and structural responses are demonstrated for a variety of structural boundary conditions (cantilevered, fixed-fixed, and pinned-pinned). The scaling analysis shows that the initial response scales properly for elastic marine structures, but the secondary bubble pulse reload caused by an underwater explosion does not follow the same scaling and may result in resonant response at full scale.

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.

scholarly journals Computational Treatments of Cavitation Effects in Near-Free-Surface Underwater Shock Analysis

2001 ◽  
Vol 8 (2) ◽  
pp. 105-122 ◽  
Author(s):  
Michael A. Sprague ◽  
Thomas L. Geers
Keyword(s):  
Free Surface ◽  
Finite Elements ◽  
Plane Wave ◽  
Single Layer ◽  
Wave Radiation ◽  
Large Array ◽  
Shock Response ◽  
Underwater Shock ◽  
Wet Surface ◽  
Fundamental Limitation

Fluid cavitation constitutes an expensive computational nuisance in underwater-shock response calculations for structures at or just below the free surface. In order to avoid the use of a large array of cavitating acoustic finite elements (CAFE), various wet-surface approximations have been proposed. This paper examines the performance of two such approximations by comparing results produced by them for 1-D canonical problems with corresponding results produced by more rigorous CAFE computations. It is found that the fundamental limitation of wet-surface approximations is their inability to capture fluid-accretion effects. As an alternative, truncated CAFE fluid meshes with plane-wave radiation boundaries are shown to give good results. In fact, a single layer of CAFE is found to be comparable in accuracy to the better of the wet-surface approximations. The paper concludes with an examination of variations in CAFE modeling.

Sign in / Sign up

Export Citation Format

Share Document