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Arturo Garcia-Perez Juan P. Amezquita-Sanchez Aurelio Dominguez-Gonzalez Ramin Sedaghati Roque Osornio-Rios Rene J. Romero-Troncoso 《浙江大学学报(A卷英文版)》2013,14(9):615-630
Structural health monitoring （SHM） is a relevant topic for civil systems and involves the monitoring, data processing and interpretation to evaluate the condition of a structure, in order to detect damage. In real structures, two or more sites or types of damage can be present at the same time. It has been shown that one kind of damaged condition can interfere with the detection of another kind of damage, leading to an incorrect assessment about the structure condition. Identifying combined damage on struc- tures still represents a challenge for condition monitoring, because the reliable identification of a combined damaged condition is a difficult task. Thus, this work presents a fusion of methodologies, where a single wavelet-packet and the empirical mode decom- position （EMD） method are combined with artificial neural networks （ANNs） for the automated and online identification-location of single or multiple-combined damage in a scaled model of a five-bay truss-type structure. Results showed that the proposed methodology is very efficient and reliable for identifying and locating the three kinds of damage, as well as their combinations. Therefore, this methodology could be applied to detection-location of damage in real truss-type structures, which would help to improve the characteristics and life span of real structures. 相似文献
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目的:本研究旨在凸显热效应在离合系统动态摩擦分析中的重要性以及将其拓展到制动系统的可能性。创新点:采用一种未被报道过的新方法从根本上整合摩擦特性、微结构组分、产热机理、摩擦片磨损和传热机制。方法:基于能量守恒原理,针对由飞轮、摩擦片和压力板构成的离合系统提出一种适用于工业应用的热分区网络解析模型。结论:1.通过实测得到的μ-ν特性表明,新的摩擦片具有磨损片子所不具备的温度敏感性。2.通过对磨损片子的微结构分析以及热导率变化的测量显示,晶格结构中铜颗粒损耗会导致其导热性能减弱。3.使用摩擦计的测量结果显示新的摩擦片相对于磨损片子具有更高的摩擦系数;较高的摩擦系数减轻了离合器啮合时产生的界面滑移的程度,从而减小了由于产热导致的摩擦功率损耗。4.根据本文发展的热学模型,新的摩擦片可通过其优良的导热性将摩擦产生的热量释放出去。 相似文献
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This study presents a framework to guide managers in the ICT industry in assessing the factors that inform the decision to participate in the development of technology standards. Using multi-criteria decision analysis and judgment data from panels of experts, a robust model is developed that comprehends the essential criteria and outcomes within the context of computer interconnect technologies. The resultant, generalizable model is validated against the case of the extant Universal Serial Bus (USB) interconnect standard and found to be congruent with the assessment of the experts. 相似文献
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Dynamic behaviour of automotive dry clutches depends on the frictional characteristics of the contact between the friction lining material, the flywheel, and the pressure plate during the clutch engagement process. During engagement due to high interfacial slip and relatively high contact pressures, generated friction gives rise to contact heat, which affects the material behaviour and the associated frictional characteristics. In practice excess interfacial slipping and generated heat during torque transmission can result in wear of the lining, thermal distortion of the friction disc, and reduced useful life of the clutch. This paper provides measurement of friction lining characteristics for dry clutches for new and worn state under representative operating conditions pertaining to interfacial slipping during clutch engagement, applied contact pressures, and generated temperatures. An analytical thermal partitioning network model of the clutch assembly, incorporating the flywheel, friction lining, and the pressure plate is presented, based upon the principle of conservation of energy. The results of the analysis show a higher coefficient of friction for the new lining material which reduces the extent of interfacial slipping during clutch engagement, thus reducing the frictional power loss and generated interfacial heating. The generated heat is removed less efficiently from worn lining. This might be affected by different factors observed such as the reduced lining thickness and the reduction of density of the material but mainly because of poorer thermal conductivity due to the depletion of copper particles in its microstructure as the result of wear. The study integrates frictional characteristics, microstructural composition, mechanisms of heat generation, effect of lining wear, and heat transfer in a fundamental manner, an approach not hitherto reported in literature. 相似文献
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The endurance time (ET) method is a time history based dynamic analysis in which structures are subjected to gradually intensifying
excitations and their performances are judged based on their responses at various excitation levels. Using this method, the
computational effort required for estimating probable seismic demand parameters can be reduced by an order of magnitude. Calculation
of the maximum displacement or target displacement is a basic requirement for estimating performance based on structural design.
The purpose of this paper is to compare the results of the nonlinear ET method with the nonlinear static pushover (NSP) method
of FEMA 356 by evaluating performances and target displacements of steel frames. This study will lead to a deeper insight
into the capabilities and limitations of the ET method. The results are further compared with those of the standard nonlinear
response history analysis. We conclude that results from the ET analysis are in proper agreement with those from standard
procedures. 相似文献
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