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Effect of Foam Cladding for Blast Mitigation:Numerical Simulation 被引量:1
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作者 MA Guowei YE Ziqing ZHANG Xingui 《Transactions of Tianjin University》 EI CAS 2006年第B09期122-125,共4页
Two numerical simulations were performed to investigate the protective effect of the foam cladding. One simulation is based on a previous experimental study, which is a ballistic pendulum with and without a foam cladd... Two numerical simulations were performed to investigate the protective effect of the foam cladding. One simulation is based on a previous experimental study, which is a ballistic pendulum with and without a foam cladding subjected to close-range blast loading. The other model is a steel beam with and without a foam cladding under blast loading. The overpressure due to the blast event can be calculated by the empirical function ConWep or by an arbitrary Lagrangian-Eulerian (ALE) coupling model. The first approach is relatively simple and widely used. The second approach can model the propagation of the blast wave in the air and the interaction between the air and the solid. It is found that the pendulum with the foam cladding always swings to a larger rotation angel compared to a bare pendulum. However, the steel beam with an appropriate foam cladding has a smaller deflection compared to the bare beam without a foam cladding. It is concluded that the protective effect of the foam cladding depends on the properties of the foam and the protected structure. 展开更多
关键词 foam material blast mitigation ALE LS-DYNA
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Evaluating the blast mitigation performance of hard/soft composite structures through field explosion experiment and numerical analysis 被引量:5
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作者 Fengyuan Yang Zhijie Li +1 位作者 Zhuo Zhuang Zhanli Liu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2022年第1期27-36,共10页
The application of hard/soft composite structure in personnel armor for blast mitigation is relatively practical and effective in realistic protection engineering,such as the shell/liner system of the helmet.However,t... The application of hard/soft composite structure in personnel armor for blast mitigation is relatively practical and effective in realistic protection engineering,such as the shell/liner system of the helmet.However,there is still lacking a reliable experi-mental methodology to effectively evaluate the blast mitigation performance when the structure directly contacts the protected target,which limits the development of protection structures.In this paper,we proposed a new method to evaluate experi-mentally and numerically the blast mitigation performance of hard/soft composite structures.The blast mitigation mechanism is analyzed.The hard/soft structures were composed of ultra-high molecular weight polyethylene(UHMWPE)composite and expanded polyethylene(EPE)foam.In field explosion experiment,a 7.0 kg trinitrotoluene(TNT)spherical charge is used to generate blast waves at a 3.8 m stand-off distance.A pressure test device is designed to support the tested structure and measure the transmitted blast pressure pulses after passing through the structure.Experimental results indicate that the hard/soft structures can mitigate the blast pressure pulse into the triangular pressure pulse,through making the pulse profile flatter,reducing the pressure amplitude,and delaying the pulse arrival time.Specifically,the combination of 7 mm UHMWPE composite and 20 mm EPE foam can reduce the blast pressure amplitude by 40%.Correspondingly,the finite element simulation is also carried out to understand the blast mitigation mechanism.The numerical results indicate that the regulation for blast pressure pulses mainly complete at the hard/soft interface,which is attributed to the reflection of pressure waves at the interface and the deformation of the soft layer compressed by the hard layer possessing kinetic energy.Furthermore,based on these analyses,the corresponding theoretical model is proposed,and it can well explain the experimental and numerical results.This study is meaningful for evaluating and designing high-performance blast mitigation structures. 展开更多
关键词 blast mitigation Composite structure Field explosion experiment Numerical simulation
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Relative performance of novel blast wave mitigation system to conventional system based on mitigation percent criteria 被引量:1
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作者 Moustafa Esa Mostafa S.Amin Ahmed Hassan 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2021年第3期912-922,共11页
Recent researches focused on developing robust blast load mitigation systems due to the threats of terrorist attacks.One of the main embraced strategies is the structural systems that use mitigation techniques.They ar... Recent researches focused on developing robust blast load mitigation systems due to the threats of terrorist attacks.One of the main embraced strategies is the structural systems that use mitigation techniques.They are developed from a combination of structural elements and described herein as conventional systems.Among the promising techniques is that redirect the waves propagation through hollow tubes.The blast wave propagation through tubes provides an efficient system since it combines many blast wave phenomena,such as reflection,diffraction,and interaction.In this research,a novel blast load mitigation system,employed as a protection fence,is developed using a technique similar to the technique of the bent tube in manipulating the shock-wave.The relative performance of the novel system to the conventional system is evaluated based on mitigation percent criteria.Performances of both systems are calculated through numerical simulation.The proposed novel system proved to satisfy high performance in mitigating the generated blast waves from charges weight up to 500 kg TNT at relatively small standoff distances(5 m and 8 m).It mitigates at least 94%of the blast waves,which means that only 6%of that blast impulse is considered as the applied load on the targeted structure. 展开更多
关键词 blast mitigation blast barriers Protection system mitigation percent Protection evaluation
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Mitigation of blast loadings on structures by an anti-blast plastic water wall 被引量:4
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作者 张力 陈力 +1 位作者 方秦 张亚栋 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第2期461-469,共9页
Seven in-situ tests were carried out in far field to study the blast mitigation effect of a kind of water filled plastic wall. Test results show that the mitigation effect of water filled plastic wall is remarkable. T... Seven in-situ tests were carried out in far field to study the blast mitigation effect of a kind of water filled plastic wall. Test results show that the mitigation effect of water filled plastic wall is remarkable. The maximum reduction of peak reflected overpressure reaches up to 94.53%, as well as 36.3% of the minimum peak reflected overpressure reduction in the scaled distance ranging from 1.71 m/kg1/3 to 3.42 m/kg1/3. Parametric studies were also carried out. The effects of the scaled gauge height, water/charge scaled distance(the distance between the explosive charge and the water wall), water wall scaled height and water/structure scaled distance(the distance between the water wall and the structure) were systematically investigated and compared with the usual rigid anti-blast wall. It is concluded that these parameters affect the mitigation effects of plastic water wall on blast loadings significantly, which is basically consistent to the trend of usual rigid anti-blast wall. Some formulae are also derived based on the numerical and test results, providing a simple but reliable prediction model to evaluate the peak overpressure of mitigated blast loadings on the structures. 展开更多
关键词 water wall blast mitigating effect protective technique prediction model
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Incidence, casualties and risk characteristics of civilian explosion blast injury in China: 2000-2017 data from the State Administration of Work Safety 被引量:4
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作者 Xu Wang Juan Du +3 位作者 Zhuo Zhuang Zheng-Guo Wang Jian-Xin Jiang Ce Yang 《Military Medical Research》 SCIE CSCD 2021年第1期1-8,共8页
Background: Civilian explosion blast injury is more frequent in developing countries, including China. However, the incidence, casualties, and characteristics of such incidents in China are unknown.Methods: This is a ... Background: Civilian explosion blast injury is more frequent in developing countries, including China. However, the incidence, casualties, and characteristics of such incidents in China are unknown.Methods: This is a retrospective analysis of the State Administration of Work Safety database. Incidents during a period from January 1, 2000 to April 30, 2017 were included in the analysis. The explosions were classified based on the number of deaths into extraordinarily major, major, serious and ordinary type. Descriptive statistics was used to analyze the incidence and characteristics of the explosions. Correlation analysis was performed to examine the potential correlations among various variables.Results: Data base search identified a total of 2098 explosions from 2000 to 2017, with 29,579 casualties: 15,788 deaths(53.4%), 12,637 injured(42.7%) and 1154 missing(3.9%). Majority of the explosions were serious type(65.4%). The number of deaths(39.5%) was also highest with the serious type(P=0.006). The highest incidence was observed in the fourth quarter of the year(October to December), and at 9:00–11:00 am and 4:00–6:00 pm of the day. The explosions were most frequent in coal-producing provinces(Guizhou and Shanxi Province). Coal mine gas explosions resulted majority of the deaths(9620, 60.9%). The number of explosion accidents closely correlated with economic output(regional economy and national GDP growth rate)(r=–0.372, P=0.040;r=0.629, P=0.028).Conclusions: The incidence and civilian casualties due to explosions remain unacceptable in developing China. Measures that mitigate the risk factors are of urgently required. 展开更多
关键词 Explosion blast exposure blast mitigation OVERPRESSURE Trauma and injury
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Shock wave mitigation using zig-zag structures and cylindrical obstructions 被引量:2
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作者 Arun Kumar R Vaibhav Pathak 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2021年第6期1840-1851,共12页
The present study focuses on the mitigation of shock wave using novel geometric passages in the flow field.The strategy is to produce multiple shock reflections and diffractions in the passage with minimum flow obstru... The present study focuses on the mitigation of shock wave using novel geometric passages in the flow field.The strategy is to produce multiple shock reflections and diffractions in the passage with minimum flow obstruction,which in turn is expected to reduce the shock wave strength at the target location.In the present study the interaction of a plane shock front(generated from a shock tube)with various geometric designs such as,1)zig-zag geometric passage,2)staggered cylindrical obstructions and 3)zigzag passage with cylindrical obstructions have been investigated using computational technique.It is seen from the numerical simulation that,among the various designs,the maximum shock attenuation is produced by the zig-zag passage with cylindrical obstructions which is then followed by zig-zag passage and staggered cylindrical obstructions.A comprehensive investigation on the shock wave reflection and diffraction phenomena happening in the proposed complex passages have also been carried out.In the new zig-zag design,the initial shock wave undergoes shock wave reflection and diffraction process which swaps alternatively as the shock front moves from one turn to the other turn.This cyclic shock reflection and diffraction process helps in diffusing the shock wave energy with practically no obstruction to the flow field.It is found that by combining the shock attenuation ability of zig-zag passage(using shock reflection and diffraction)with the shock attenuation ability of cylindrical blocks(by flow obstruction),a drastic attenuation in shock strength can be achieved with moderate level of flow blocking. 展开更多
关键词 blast wave mitigation Blockage ratio Geometric obstructions Shock wave reflection and diffraction Zig-zag structure
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Investigation of Supersonic Shock Wave Loading on Thin Metallic Sheets
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作者 Khushi Ram Kartikeya Kartikeya +1 位作者 Puneet Mahajan Naresh Bhatnagar 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第11期10-14,共5页
Shock tube experiments were carried out to investigate dynamic behavior of Ultra-high hardness(UHH)steel and Aluminium(Al) sheets of 0.8 mm thickness at 0.55, 0.9 and 1.18 MPa peak-over pressure.Experimental results s... Shock tube experiments were carried out to investigate dynamic behavior of Ultra-high hardness(UHH)steel and Aluminium(Al) sheets of 0.8 mm thickness at 0.55, 0.9 and 1.18 MPa peak-over pressure.Experimental results showed that center point deflection increases with an increase in peak-over pressure for Al sheets. However, UHH steel sheets showed negligible deformation when loaded at low peak-over pressures and showed sudden brittle failure at high peak-over pressures. Similar results were obtained by quasi-static testing, UHH steel failed abruptly while Al showed ductile behavior. Results from literature indicate that to protect structures against shock loading it is necessary that they dissipate energy via plastic deformation. The Al sheets were shown to deform plastically both in quasi-static and shock loading. Thus, hardness along with ductility is required to dissipate supersonic shock waves. 展开更多
关键词 Shock tube Peak-over pressure Shock wave blast mitigation Plastic deformation
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Introduction to Enhanced Protective Film Systems
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作者 LIU Chunlin DAVID Palermo +2 位作者 LI Guoqiang SUN Jianyun CHEN Suwen 《Transactions of Tianjin University》 EI CAS 2008年第B10期491-494,共4页
An explosive blast mitigation alternative has increased the safety of structures by using " catcher" systems. These systems " catch" or repel the failure of the window or in-fill wall pro-tecting l... An explosive blast mitigation alternative has increased the safety of structures by using " catcher" systems. These systems " catch" or repel the failure of the window or in-fill wall pro-tecting life and property from ballistic shards or fragments. They can be designed to be stand-alone in new construction and structural retrofits or used to augment structural hardening tech-niques. Cables, fabrics, and thin gauge sheet steel are examples of catcher systems used in the past. A new and evolving category of catcher systems are based on polymeric materials that can be used for both wall and window upgrades. These products are a proven blast mitigation concept and K&C Protective Technologies Pte Ltd (KCPT) together with Sherwin-Williams(SW) use KCPT′s blast engineering capacity and SW′s material engineering principles to create engineered systems for even greater in-use performance. 展开更多
关键词 explosion blast mitigation catcher system protective film systems
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