Damage effect of pile wharf under underwater explosion load

2021 ◽  
pp. 1-19
Author(s):  
Shuanzhu Tian ◽  
Xiuli Du ◽  
Qiushi Yan ◽  
Jun Wu ◽  
Tieshuan Zhuang
Keyword(s):  
Underwater Explosion ◽  
Damage Effect ◽  
Explosion Load

The influence of strain rate on the cavitation time and deformation of an underwater impulsively rectangular plate

2021 ◽  
pp. 030932472110208
Author(s):  
Habib Ramezannejad Azarboni ◽  
Abolfazl Darvizeh
Keyword(s):  
Constitutive Equation ◽  
Strain Rate ◽  
Rectangular Plate ◽  
Total Pressure ◽  
Elastoplastic Deformation ◽  
Underwater Explosion ◽  
Strain Rate Effect ◽  
Linear Solution ◽  
Explosion Load ◽  
Explosive Forming

The effect of strain rate on the cavitation time and elastoplastic deformation of steel rectangular plate subjected to underwater explosion load is analytically and numerically investigated in this study. At the cavitation time, the total pressure of the explosion is eliminated so that the cavitation time plays a significant role in the elastoplastic deformation of underwater explosive forming of plate. Taking into account the strain rate effect, the Cowper-Symond constitutive equation of mild steel is employed. Exact linear solution using the Eigen function and numerical linear and nonlinear solution using finite difference method (FDM) of dynamic response of impulsively plate is obtained. Implementing the linear work hardening, the stress, strain, displacement, and velocity in any steps of loading are calculated. The time of cavitation can be recognized in elastic or plastic regimes by applying the Cowper-Symond constitutive equation. Considering the strain rate influence, the effects of charge mass and standoff are investigated to occur of cavitation and time dependent deflection and velocity of a rectangular plate.

Simulation Study on Tapered and Spherical Shaped Charge under Underwater Explosion

2012 ◽  
Vol 157-158 ◽  
pp. 852-855
Author(s):  
Fang Yi Zhou ◽  
Tao Jiang ◽  
Wei Li Wang ◽  
Fa Min Zhan ◽  
Ke Yu Zhang
Keyword(s):  
Numerical Simulation ◽  
Stress Distribution ◽  
Simulation Study ◽  
Underwater Explosion ◽  
Shaped Charge ◽  
Damage Effect ◽  
Tapered Angle ◽  
Underwater Target ◽  
Shaped Charge Jet

For improving the damage effect to underwater target of warhead, a kind of metamorphic tapered angle shaped charge is designed, and the damge mechanism is analyzed. The physics modle of tapered and spherical shaped charge under underwater explosion is built, numerical simulation is done by LS-DYNA, the stress distribution and velocity of jet are got. The result shows that the shaped charge jet formed by this kind of structure can provide moving space for latter EFP, which improving the damage effect to target.

Wall effect of underwater explosion load based on wave motion theories

2014 ◽  
Vol 28 (5) ◽  
pp. 587-598 ◽  
Author(s):  
Wei Xiao ◽  
Xiong-liang Yao ◽  
Jun Guo
Keyword(s):  
Wave Motion ◽  
Underwater Explosion ◽  
Wall Effect ◽  
Explosion Load

Investigation of the Effect of the Deck Simulator on the Shock Spectrum of Floating Shock Platform

2016 ◽  
Author(s):  
Yao Xiongliang ◽  
Cui Xiongwei ◽  
Wang Jun ◽  
Zhang Wenqi
Keyword(s):  
Underwater Explosion ◽  
Structural Difference ◽  
Body Motion ◽  
Structural Form ◽  
The Real ◽  
Assessment Tests ◽  
Shock Environment ◽  
Explosion Load ◽  
The Impact ◽  
Is Design

The investigation of the effect of the deck simulator on the shock spectrum of floating shock platform is conducted in this paper. Generally, the impact assessment tests of large-medium sized shipboard equipment are conducted on the floating shock platform. The structural form of the floating shock platform is similar to the barge’s structural form, with a strong double bottom which can ensure the safety of the bottom structure under the underwater explosion load. The tested equipment is fixed on the inner bottom plating as same as it is fixed on the real ship. It is obvious that there is a huge structural difference between floating shock platform and the real ship. The response of the real ship under explosion load is flexible-body motion, while the main response of the floating shock platform is rigid-body motion[1]. The deck can be regarded as a filter acting on the shock environment which can cause difference between the shock environments of ship and floating shock platform[2]. To decrease the shock environment difference, a special deck which is called deck simulator here is design. Through the numerical simulation and analysis, the FSP with a deck simulator can decrease the shock environment difference and can be used to test equipment with special mounting frequency demand. These conclusions have a certain guiding significance for the assessment of ship equipment in engineering applications.

The Effect of Roundness on the Buckling Strength for the Submerged Pressure Hull

2014 ◽  
Vol 644-650 ◽  
pp. 5133-5137
Author(s):  
Ching Yu Hsu ◽  
Cho Chung Liang ◽  
Tso Liang Teng ◽  
Chia Wei Chang
Keyword(s):  
Underwater Explosion ◽  
Cylinder Pressure ◽  
Pressure Loading ◽  
Finite Element Program ◽  
Buckling Strength ◽  
Element Program ◽  
Analysis Models ◽  
Explosion Load ◽  
Very High ◽  
Design Pressure

The pressure hull is the most important part of resisting pressure structures of the structural systems. The submerged pressure hull is subjected to very high hydrostatic pressure or underwater explosion load, which creates large compressive stress resultants. Due to this the pressure hull is susceptible to buckling. Buckling phenomena analysis is of greater importance in the design of the submerged pressure hulls. For the pressure hulls with local out-of-roundness, the operating depth will be greatly influenced and thus decreasing capability to resist pressure loading. Thus, this work employs the ABAQUS finite element program to analyze the effect of roundness on the buckling strength for the cylinder pressure hull. Sex kinds of out-of-roundness rateφ, 0%, 1%, 3%, 5%, 10% and 15%, were studied in this study. The bulking depth and collapse depth for the cylinder pressure hull with different out-of-roundness rate were calculated. The Analysis models and results of this study contribute to efforts to design pressure hull structures.

scholarly journals Research on the escape mechanism and influencing factors of harmful gas induced by blasting excavation in deep rock tunnel

2021 ◽  
Author(s):  
Yi Luo ◽  
Hangli Gong ◽  
Dengxing Qu ◽  
Xinping Li ◽  
Shaohua Hu ◽  
...  
Keyword(s):  
Coupling Effect ◽  
In Situ Stress ◽  
Surrounding Rock ◽  
Water Soluble ◽  
Damage Effect ◽  
Escape Mechanism ◽  
Blasting Excavation ◽  
Deep Rock ◽  
Explosion Load

Abstract The escape of toxic and harmful gases is a common disaster effect in tunnel engineering. Frequent drilling and blasting excavation disturbances under high in-situ stress environment will inevitably lead to cumulative damage effect on surrounding rock, which will increase the permeability coefficient of surrounding rock, increase the risk of toxic and harmful gas escape, and seriously endanger construction safety. In this paper, based on real-time monitoring data of harmful gases during blasting and excavation of Yuelongmen Tunnel on Chengdu-Lanzhou Railway, this study summarized laws and distribution characteristics of harmful gas escape intensified by the blasting excavation, and the effectiveness of shotcreting and grouting for water blocking to inhibit gas escape is verified. Then, taking water-containing and gas-containing voids as carriers, considering the influence of different in-situ stress, explosion load and void parameters (including void pressure, void diameter and distance between void and tunnel), to carry out research on the escape mechanism of water-soluble (H 2 S) and insoluble (CH 4 ) toxic and harmful gases under the coupling effect of stress-seepage-damage. The relationship between the amount of harmful gas escaped and the damage degree of the surrounding rock of the tunnel is analyzed, and the functional relationship between it and the in-situ stress, explosion load and cave parameters is established. The results further demonstrate that the amount of escaped harmful gases, such as methane and H 2 S is closely related to lithology of surrounding rock, occurrence conditions of the deep rock mass, development degree of structural fractures and void parameters. The damage of surrounding rock caused by dynamic disturbance during blasting excavation is the main reason of aggravating harmful gas escape. The research results can provide a theoretical reference for preventing harmful gas from escaping in the similar engineering construction.

A Numerical Study on Shock Wave Characteristics for the Underwater Explosion

2012 ◽  
Vol 594-597 ◽  
pp. 2680-2683
Author(s):  
Wei Ju ◽  
Yi Liu ◽  
Jue Ding
Keyword(s):  
Shock Wave ◽  
Numerical Study ◽  
Bubble Formation ◽  
Underwater Explosion ◽  
Scientific Basis ◽  
Energy Output ◽  
Damage Effect ◽  
Variable Step Size ◽  
Step Size ◽  
Output Characteristics

Underwater explosion is very important for underwater weapons-design technology and research on the damage effect of target structure. In this paper, the flow-out boundary and variable step-size multi-material Euler algorithm were utilized to analyze numerically the whole process of shock wave generation and propagation, as well as bubble formation and impulse of underwater explosion. The computed results reveal the energy output characteristics of underwater explosion by TNT charge, which provide an important scientific basis for formulation design of charge and improvement of damage effects for underwater target.

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