Blast resistance evaluation of urban utility tunnel reinforced with BFRP bars

To improve corrosion-resistance of shallow-buried concrete urban utility tunnels(UUTs),basalt fiber reinforced polymer(BFRP)bars are applied to reinforce UUTs.As the UUT must have excellent survival capability under accidental explosions,a shallow-buried BFRP bars reinforced UUT(BBRU)was designed and constructed.Repetitive blast experiments were carried out on this BBRU.Dynamic responses,damage evolutions and failure styles of the BBRU under repetitive explosions were revealed.The tunnel roof is the most vulnerable component and longitudinal cracks develop along the tunnel.When the scaled distance is larger than 1.10 m/kg1/3,no cracks are observed in the experiments.When the BBRU is severely damaged,there are five cracks forming and developing along the roof.The roof is simplified as a clamped-supported one-way slab,proved by the observation that the maximum strain of the transverse bar is much larger than that of the longitudinal bar.Dynamic responses of the roof slab are predicted by dynamic Euler beam theory,which can consistently predict the roof displacement under large-scaled-distance explosion.Compared with the UUT reinforced with steel bars,the BBRU has advantages in blast resistance with smaller deflections and more evenly-distributed cracks when the scaled distance is smaller than 1.260 m/kg1/3 and the steel bars enter plastic state.Longer elastic defamation of the BFRP bars endows the UUT more excellent blast resistance under small-scaled-distance explosions.     

A cooperative interference resource allocation method based on improved firefly algorithm

To deal with the radio frequency threat posed by modern complex radar networks to aircraft, we researched the unmanned aerial vehicle (UAV) formations radar countermeasures, aiming at the solution of radar jamming resource allocation under system countermeasures. A jamming resource allocation method based on an improved firefly algorithm (FA) is proposed. Firstly, the comprehensive factors affecting the level of threat and interference efficiency of radiation source are quantified by a fuzzy comprehensive evaluation. Besides, the interference efficiency matrix and the objective function of the allocation model are determined to establish the interference resource allocation model. Finally, A mutation operator and an adaptive heuristic are integtated into the FA algorithm, which searches an interference resource allocation scheme. The simulation results show that the improved FA algorithm can compensate for the deficiencies of the FA algorithm. The improved FA algorithm provides a more sci-entific and reasonable decision-making plan for aircraft mission allocation and can effectively deal with the battlefield threats of the enemy radar network. Moreover, in terms of convergence accuracy and speed as well as algorithm stability, the improved FA algorithm is superior to the simulated annealing algorithm (SA), the niche genetic algorithm (NGA), the improved discrete cuckoo algorithm (IDCS), the mutant firefly algorithm (MFA), the cuckoo search and fireflies algorithm (CSFA), and the best neighbor firefly algorithm (BNFA).     

A novel launch dynamics measurement system for multiple launch rocket system and comparative analysis with numerical simulations

In this paper,a novel launch dynamics measurement system based on the photoelectric sensor pair is built.The actual muzzle time(i.e.a time duration that originates from the initial movement to the rocket's departure from the muzzle)and the muzzle velocity are measured.Compared with the classical methods,the actual muzzle time is obtained by eliminating the ignition delay.The comparative analysis method is proposed with numerical simulations established by the transfer matrix method for multibody systems.The experiment results indicate that the proposed measurement system can effectively measure the actual muzzle time and reduce the error of classical methods,which match well with the simulation results showing the launch dynamics model is reliable and helpful for further analysis and design of the MLRS.     

耐1200℃陶瓷瓦重复使用性能

针对目前比较成熟的耐1 200℃陶瓷瓦开展了1 200℃多次重复热处理,研究了陶瓷瓦的结构和性能演变行为和重复使用性能。结果表明:1 200℃热处理20次后,耐1 200℃陶瓷瓦表现出良好的宏观热稳定性;重复热处理过程中,纤维间烧结,黏接熔融和石英纤维析晶及晶粒长大,使纤维直径发生变化,出现缩颈,进而导致了Z向收缩,收缩率达14%,从而使得压缩强度略有增大,隔热性能降低;经过1 260℃、11次单面辐射加热后,Z向收缩率为5.58%,隔热效果降低了7.59%,但隔热材料能够在6次重复加热后保持材料隔热性能不降低。     

基于情景模型的重大突发事件人员应急疏散方法

针对重大突发事件人员应急疏散难题,提出了基于情景应对的应急决策方法.将重大突发事件相关关键属性表示为一系列情景,对情景进行定性与定量相结合的描述.以疏散时间作为决策收益的判断标准,引入交通流量算法并考虑安全距离,建立数学模型.通过计算机仿真应急疏散算例,求解决策的最优解,验证了方法的有效性.     

作战辅助决策模型设计及评估方法

作战辅助决策模型是在复杂战场态势下,辅助指挥人员科学、高效决策的重要工具.针对当前辅助决策模型功能分散、可信性不足、缺乏工程化设计与管理等问题,从系统工程角度出发,开展作战辅助决策模型构建与评估通用方法的研究,提出辅助决策模型工程化设计与评估分级的一般流程与方法,并结合实例进行说明.     

基于超网络的近距空中支援信息流转模式构建

稳健灵活的信息流转模式是近距空中支援顺利实施的重要保障.针对近距空中支援信息流转模式构建问题,建立基于超网络的作战信息流转"两层四网"模型.根据作战经验,分析近距空中支援作战的主要作战力量及基本流程,抽象出相应的作战节点和信息关系,以此建立近距空中支援作战信息流转超网络模型.针对超网络节点的超度分布、网络弹性等特性进行仿真实验.仿真结果表明,当前近距空中支援超网络具有一定的合理性和稳定性,同时为下一步优化作战网络结构提供了参考.     

WSNs中基于鸡群优化算法选择簇头的簇路由

能量是无线传感网络(Wireless Sensor Networks,WSNs)的重要资源.有效地利用节点能量可延长网络寿命.簇技术是提高资源分配、缓解网络能耗的有效策略.提出基于鸡群优化算法选择簇头的簇路由(Chicken Swarm Optimization-based Cluster Head Selecting Clustering Routing,CSO-CHS).CSO-CHS路由先从能量角度构建目标函数,再利用鸡群优化算法产生最优鸡群,进而形成最优的簇.通过最优的簇,平衡节点间能耗,进而实现延长网络寿命的目的 .仿真结果表明,相比于同类算法,CSO-CHS路由缓解了节点能耗速度,延长了网络寿命.