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Ballistic impact response of flexible and rigid UHMWPE textile composites:Experiments and simulations

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Defence Technology（防务技术） 2023年第4期22卷 37-53页

作者： Hongxu Wang Dakshitha Weerasinghe Paul J.Hazell damith mohotti Evgeny V.Morozov Juan P.Escobedo-Diaz School of Engineering and Information Technology The University of New South WalesCanberraACT2600Australia

This study elaborates on the effects of matrix rigidity on the high-velocity impact behaviour of UHMWPE textile composites using experimental and numerical *** composite samples were manufactured of a plain-weave fabric(comprising Spectra?1000 fibres)and four different matrix ***-velocity impact tests were conducted by launching a spherical steel projectile to strike on the prepared samples via a gas *** experimental results showed that the textile composites gradually changed from a membrane stretching mode to a plate bending mode as the matrix rigidity and thickness *** composites deformed in the membrane stretching mode had higher impact resistance and energy absorption capacity,and it was found that the average energy absorption per ply was much higher in this mode,although the number of broken yarns was smaller in the perforated ***,the flexible matrix composites always had higher perforation resistance but larger deformation than the rigid matrix counterparts in the tested thickness and velocity range.A novel numerical modelling approach with enhanced computational efficiency was proposed to simulate textile composites in mesoscale *** simulation results revealed that stress and strain development in the more rigid matrix composite was localised in the vicinity of the impact location,leading to larger local deformation and inferior perforation resistance.

关键词： Impact behaviour Textile composite UHMWPE fibre Energy absorption Finite element analysis

Evaluation of effectiveness of polymer coatings in reducing blastinduced deformation of steel plates

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Defence Technology（防务技术） 2021年第6期17卷 1895-1904页

作者： damith mohotti P.L.N.Fernando Dakshitha Weerasinghe Alex Remennikov School of Engineering and Information Technology The University of New South WalesCanberraACT2600Australia Department of Civil Engineering Faculty of EngineeringGeneral Sir John Kotelawala Defence UniversityRatmalanaSri Lanka School of Civil Engineering Faculty of EngineeringThe University of SydneyDarlingtonNSW2006Australia Centre for Infrastructure Protection and Mining Safety University of WollongongWollongongNSW2522Australia

Incorporating elastomers such as polymers in protective structures to withstand high energetic dynamic loads,has gained significant *** main objective of this study is to investigate the influence of a Polyurea coating towards the blast-induced response in steel *** such,Polyurea coated steel plates were tested under near-field blast loads,produced by the detonation of 1 kg of spherical nitromethane charges,at a standoff distance of 150 *** steel(XLERPLATE 350)and high-strength steel(BIS80)plates with thicknesses of 10 mm were Polyurea coated with thicknesses of 6 mm and 12 mm on either the front(facing the charge)or the back *** deformation profiles were measured using 3D *** simulations were performed using the non-linear finite element code *** strain-dependent behaviour of the steel and Polyurea were represented by Johnson-cook and Money-Rivlin constitutive models,*** numerical models were validated by comparing the plate deflection results obtained from the experiments and were then used in the subsequent parametric study to investigate the optimum thickness of the Polyurea *** results indicate that back face coating contributes towards an approximately 20%reduction in the residual deformation as well as the absence of melting of the Polyurea layer,while the front-face coating can be used a means of providing additional standoff distance to the steel plates.

关键词： Polyurea coating Near-field blast LS-DYNA Plate deformation ALE

A simplified approach to modelling blasts in computational fluid dynamics (CFD)

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Defence Technology（防务技术） 2023年第5期23卷 19-34页

作者： D.mohotti K.Wijesooriya S.Weckert School of Engineering and Information Technology The University of New South WalesCanberraACT2600Australia Sensors and Effectors Division Defence Science and Technology GroupEdinburghSA5111Australia

This paper presents a time-efficient numerical approach to modelling high explosive(HE)blastwave propagation using Computational Fluid Dynamics(CFD).One of the main issues of using conventional CFD modelling in high explosive simulations is the ability to accurately define the initial blastwave properties that arise from the ignition and consequent *** codes often employ Jones-Wilkins-Lee(JWL)or similar equation of state(EOS)to simulate ***,most available CFD codes are limited in terms of EOS *** are restrictive to the Ideal Gas Law(IGL)for compressible flows,which is generally unsuitable for blast *** this end,this paper presents a numerical approach to simulate blastwave propagation for any generic CFD code using the IGL EOS.A new method known as the Input Cavity Method(ICM)is defined where input conditions of the high explosives are given in the form of pressure,velocity and temperature time-history *** time history curves are input at a certain distance from the centre of the *** is shown that the ICM numerical method can accurately predict over-pressure and impulse time history at measured locations for the incident,reflective and complex multiple reflection scenarios with high numerical accuracy compared to experimental *** ICM is compared to the Pressure Bubble Method(PBM),a common approach to replicating initial conditions for a high explosive in Finite Volume *** is shown that the ICM outperforms the PBM on multiple fronts,such as peak values and overall overpressure curve ***,the paper also presents the importance of choosing an appropriate solver between the Pressure Based Solver(PBS)and Density-Based Solver(DBS)and provides the advantages and disadvantages of either *** general,it is shown that the PBS can resolve and capture the interactions of blastwaves to a higher degree of resolution than the *** is achieved at a much higher computational cos

关键词： Blast loads Computational fluid dynamics Explosions Numerical simulations

Contamination Sources of Bomuruella Reservoir at Nuwara Eliya

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Journal of Environmental Protection 2011年第3期2卷 271-279页

作者： Randika Anjalie Jayasinghe Nilanthi J. G. J. Bandara Keerthi Meepe mohotti 不详

Bomuruella Reservoir in Nuwara Eliya is an important water source in the area which indirectly contributes to the drinking water supply of the downstream people. Many agricultural lands obtain water from this reservoir and consume its water for washing and cleaning purposes. This research was focused on identifying the contamination sources of Bomuruella reservoir and to investigate the suitability of the reservoir as a drinking water *** to the water quality analysis, BOD5 and CODMn values of most sample points did not satisfy the specified standards of Central Environmental Authority, Sri Lanka. Municipal wastewater stream and the stream from the cultivated area recorded high BOD5 levels of 7.65 mg/l and 6.55 mg/l respectively in the period of low water level of the reservoir. The stream from the cultivated area reported a high CODMn value of 595.74 mg/l during March and the stream from Kandapola plantation recorded a CODMn value of 74.44 mg/l during May. This concludes that the reservoir was contaminated with significant loads of organic wastes. Furthermore, the effluent from the leachate treatment plant recorded higher conductivity, nitrate and CODMn values which indicated that the leachate treatment plant was *** main cause of pollution of the reservoir is the discharge of agricultural runoff, raw sewage and wastes which include domestic, industrial and hospital waste directly into the feeder streams. It can be concluded that if the reservoir is to be used as a source of drinking water stringent measures have to be taken to control effluents.

关键词： Water Quality Contamination Sources Bod5 Codmn Leachate

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物联网RFID多领域应用解决方案

21世纪独一无二的无线电创新构建可缩放的全球射频识别网络

作者： (澳) damith C. Ranasinghe (澳) Quan Z. Sheng (美) Sherali Zeadally

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国外科技新书评介 2012年第3期 10-11页

作者： damith C. Ranasinghe 王岳不详中国科学院空间科学与应用研究中心博士生

近年来，无线通信、中间件以及互联网等技术的飞速发展推动了射频识别（RFID）技术的不断演进，射频识别技术已经成为“物联网（Internet of Things）”的一个不可或缺的组成部分。在未来的“物联网”环境中，我们日常生活中物理存在的... 详细信息

近年来，无线通信、中间件以及互联网等技术的飞速发展推动了射频识别（RFID）技术的不断演进，射频识别技术已经成为“物联网（Internet of Things）”的一个不可或缺的组成部分。在未来的“物联网”环境中，我们日常生活中物理存在的物体是可识别的、可读的、可寻址的，甚至是可控制的，这种连接并融合物理世界和虚拟世界的能力不仅会改变我们的生活，

关键词：射频识别技术无线电创新网络缩放虚拟世界无线通信组成部分