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91.
杨瀚涛 《国外电子测量技术》2017,36(5):107-110
在介绍Swerling目标模型的基础上,研究了网络协同雷达对Swerling起伏目标的检测性能。分析了单站雷达对Swerling起伏目标的检测性能,进而推广到网络协同雷达对Swerling起伏目标的检测,并给出了网络协同雷达对单个多起伏特性目标的检测性能的仿真结果,为研究目标起伏与网络协同雷达系统设计提供了理论依据。 相似文献
92.
在研究故障预测与健康管理(PHM)技术体系构建、数据采集与运用、系统状态监测与故障预测、验证评估等发展现状的基础上,结合新阶段装备PHM工程应用现状,从装备测试性设计与验证、多源故障信息交互与管理、寿命预测与维修支持、验证评估及标准制定等方面分析军用飞机PHM技术面临的瓶颈问题,并指出应重点开展包括测试性试验技术、智能信息处理与融合技术、航空装备与信息标准化管理技术、数据挖掘与平台构建技术等方面的研究,最后对我国PHM技术的发展给出思考与建议。 相似文献
93.
94.
T. M. J. Rakotomahefa Feng Wang Shugang Wang 《Journal of Building Performance Simulation》2018,11(5):538-552
A ventilated wall module is an outdoor air-intake device that can clean the drawn air, reduce heat loss or gain, and insulate outdoor noises. It contains a solar board, air cavities, and an air filter. This investigation proposes a zonal network model to efficiently predict temperature profiles in a ventilated wall module. The thermal network is established by applying an energy balance to each network node. The outdoor temperature, indoor temperature, and solar irradiation intensity are specified as boundary parameters. The proposed model is validated by the measured temperatures in a prototype model. The results show that the proposed model provides reasonably accurate temperatures with a maximum gap of 3°C between the prediction and the measurement. The temperature profiles approach straight lines when the mass flow rate significantly increases. A similar trend is observed when the solar irradiation intensity, the solar board absorptivity, or the glass transmitivity dramatically decreases. 相似文献
95.
S.A. Brideau I. Beausoleil-Morrison M. Kummert 《Journal of Building Performance Simulation》2018,11(4):449-469
While some building energy simulation tools include dedicated models to represent thermally massive embedded-tubes radiant floor systems, there are no models available for lightweight above-floor tube-and-plate (AFTP) systems. AFTP systems consist of a grooved wooden subfloor (or high density insulation layer), and conductive fin. This paper discusses the development of a transient AFTP radiant floor model and its implementation into ESP-r. This AFTP radiant floor model uses the general approach of the existing embedded-tube model in ESP-r and combines an analytical model of the tube with a two-dimensional finite difference model of the top layers of the floor construction. The new AFTP radiant floor model was found to compare closely with a transient two-dimensional finite element analysis model. Additionally, a full-scale transient experiment was conducted to empirically validate the model. The new model's predictions were found to be in close agreement with the measurements from this experiment. 相似文献
96.
为解决交叉隧道的安全性评定问题,类比边坡工程中的强度折减法,以既有隧道允许的最大沉降值为判据提出交叉间距折减法。应用FLAC3D软件模拟探究了不同覆土厚度、交叉角度对上部既有隧道的影响规律。当交叉角度为90°,覆土厚度分别为15、20、24、30 m时的临界交叉间距为3、4.5、7、11 m。当覆土厚度为26 m,交叉角度分别为0°、30°、45°、60°、90°时的安全净间距为6.8、7.6、8.9、8.1、7.4 m。结果表明,新建隧道对既有隧道的影响随覆土厚度增加而增大,随交叉角度增大呈现先增大后减小的趋势。为验证方法的合理性,以盘道岭隧道为背景对3种支护方案进行了交叉间距折减检验进行安全性评估。现场监测表明,开挖前进行的管棚支护较好地控制了对上部公路隧道的影响。 相似文献
97.
《Structure and Infrastructure Engineering》2013,9(8):777-793
Precast girders have recently been widely employed in the construction of bridges and viaducts. The new bridge over the Tagus River in Portugal, the Lezíria Bridge, comprehends a 9160 m long south approach viaduct, which was built with precast girders made continuous in situ. Given the relevance of this construction, a long-term monitoring system was implemented and measurements were taken since the start of the construction. The observed parameters were concrete strains and temperatures, deck rotations, joint displacements, accelerations and also environment temperature and relative humidity. The work presents the precast structure, the monitoring system and the appraisal of a statistical procedure for the long-term assessment of the structural behaviour. This procedure is based on prediction models, which establish the normal correlation patterns between environmental and material parameters (such as concrete temperature and shrinkage strains), and the observed structural response in terms of strains, rotations and movements of expansion joints. The calculation of the normal correlation pattern comprehends the minimisation of a square error. By applying the prediction model to the structural response measured in the south approach viaduct of the Lezíria Bridge, it was found that this methodology is a feasible tool for real-time damage detection of bridges. 相似文献
98.
《Structure and Infrastructure Engineering》2013,9(12):1251-1266
This paper aims at developing an innovative technique of concurrent multi-objective optimisation for updating the multi-scale model of long-span bridges. A multi-scale model is established for the purpose of concurrently analysing the global response of the structure and nonlinear local damages in order to assess structural state and local damage evolution or deteriorating, respectively. A multi-objective optimisation technique is proposed in this work for concurrent multi-scale model updating, in which several key issues including the determination of the objective functions and constraint conditions, the multi-objective optimisation algorithm and how to find the optimal solution from many non-inferior solutions are studied. The proposed concurrent multi-objective optimisation technique is applied to update the initial multi-scale model of Runyang Suspension Bridge (RYSB) near Shanghai, and the updated model is validated by the data from the field tests conducted for obtaining the response in global (dynamic properties) and local levels. 相似文献
99.
100.
道路横断面的设计与规划,在城市的交通安全便捷、整体景观与形象以及土地资源的合理利用等方面有着重大的意义。城市道路建设用地缺乏与机动车迅猛增长的矛盾日益突出,必须合理设计道路横断面,确保交通的可持续发展。 相似文献