Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Study on Optimization Design of Black Box of Offshore Test System for Underwater Explosion Test
Haisong Xiao1, Jinchao Zhu2, Zeyu Shi1, Yue Tian2
1, Marine Design & Research Institute of China
2, AVIC Shanghai Aviation Electric Co.,LtdShanghai, PR China

ABSTRACT

Hunter and Geers (2004) analyzed the load characteristics of bubbles indifferent stages, adopted different calculation models in the initialshock-wave phase and oscillation phase, and proposed the distribution
law of pressure field and velocity field of underwater explosion bubbles.
Klaseboer et al. (2005) conducted an experimental study on thecomplex fluid structure coupling phenomenon of underwater explosion
in a specially designed explosion test tank, discussed the phenomena
such as bubble jetting and bubble migration towards the structure, andanalyzed the characteristics of bubble load in underwater explosion indetail. Jin et al. (2020) analyzed the load of cavitation collapse
characteristics of underwater explosion, focusing on the evolution ofcavitation zone, pressure distribution near the structure and theresponse of the structure under underwater explosion load. Therefore,
the particularity of underwater explosion load should be fully
considered in the shock resistance optimization design of black box.
Gong and Lam (2015) studied the response of glass-epoxy composite
hull under underwater explosion load, and analyzed the shock
resistance of composite hull and a steel hull through comparison. Yin etal. (2016) discussed the impact resistance of pressure hull and pointed
out that the damage of pressure hull under underwater bubble load canbe effectively reduced by adding cellular claddings. Ren et al. (2019)analyzed the shock resistance of water-backed sandwich panel andcompared it with that of air-backed sandwich panel with the same
configurations, which can provide guidance for the design of shock
resistant structure.

When carrying out large-scale underwater explosion test using floating
shock platform or real ship, it can be considered to set up a black box torecord and store the test data. However, under the conventional design,
the internal structure of the black box may fail under some assessment
conditions of underwater explosion test. Aiming at the weak link of theshock resistance of the black box, five optimization schemes of theshock resistance of the black box are designed from the perspectives ofstructural optimization and material optimization, and the shock
response of the black box under these five schemes is numericallycalculated. According to the calculation results, the final optimization
scheme is determined.

KEY WORDS: Underwater Explosion; Black Box; Shock Resistance;
Optimization Design

INTRODUCTION
Due to the strong nonlinearity and complexity of underwater explosion,
the research on underwater explosion needs to carry out a large numberof experiments to explore some specific phenomena and explain therelevant mechanical problems, so as to make up for the deficiency ofnumerical calculation methods. Among them, large-scale or even realscale underwater explosion tests are particularly important. Large scaleand real-scale underwater explosion tests usually need to be carried out
on various floating shock platforms or real ships. In the previous
research (Xiao et al., 2021), a black box which can be applied to theoffshore test system of underwater explosion test such as shock
platform and real ship is designed, which puts forward a new solution
for the recording and storage of data in the test. However, theconventional black box is difficult to resist the shock load under allassessment conditions of underwater explosion test, so it is necessary to
carry out the shock resistance optimization design of black box. Theloads produced by underwater explosion are very complex. Comparedwith air explosion, the transient loads such as shock wave, bubble
pulsation and bubble jet produced by underwater explosion havedifferent damage modes to ship structure and ship borne equipment.

Using the ideas of other scholars for reference, in this study, aiming at
the weak link of shock resistance of traditional black box, theoptimization design of black box is carried out from two aspects ofstructural form and material. The structure optimization mainly
considers three optimization methods: changing the installation modeof hard disk, increasing the thickness of insulation damping layer andadding buffer material layer. Considering the various shell materials,
the porous composite foam aluminum is used as the insulation damping
layer to optimize the material of the black box, in order to further
improve the shock resistance of the black box. By means of numericalcalculation, the proposed optimization schemes are compared, analyzed
and evaluated.

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