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高动应力水平下软粘土动力特性研究及应用 被引量:1
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作者 王元战 李世纪 雷继超 《水道港口》 2020年第1期99-106,共8页
软粘土在受到不同应力水平动荷载作用时动力特性差异较大,在低水平动应力作用下土体强度呈现循环弱化并趋于稳定状态,在高水平动应力作用下土体强度会发生循环破坏,高、低动应力水平的临界值称为临界动应力。目前研究大多针对低水平动... 软粘土在受到不同应力水平动荷载作用时动力特性差异较大,在低水平动应力作用下土体强度呈现循环弱化并趋于稳定状态,在高水平动应力作用下土体强度会发生循环破坏,高、低动应力水平的临界值称为临界动应力。目前研究大多针对低水平动应力作用下土体强度循环弱化问题。针对烟台港淤泥质粉质粘土开展了一系列动三轴试验,探究淤泥质粉质粘土的临界动应力变化特性及土体在高水平动应力下的强度变化规律,研究了不同围压、不同固结静偏应力和不同超固结比条件下软粘土的动力特性。通过对动强度试验数据的统计分析,给出了土体临界动应力随固结围压的变化规律,得到了综合考虑循环次数、围压、静偏应力和超固结比的土体动强度模型。依据已有的低水平动应力下循环强度弱化模型和建立的高水平动应力下动强度模型,通过二次开发将其在ABAQUS软件中实现,建立了综合考虑不同动应力水平下土体强度循环弱化和循环破坏的有限元数值模型,并通过实例研究了土体强度循环破坏对地基承载力的影响。 展开更多
关键词 循环荷载 软土 力特性 临界应力 动强度模型
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Application of the Sub-Model Method in the Engine Strength Analysis 被引量:9
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作者 邹文胜 左正兴 +1 位作者 冯慧华 廖日东 《Journal of Beijing Institute of Technology》 EI CAS 2001年第3期260-265,共6页
On the basis of introducing the fundamental theory and the basic analysis steps of the sub model method, the strength of the new engine complex assembly structure was analyzed according to the properties of the engin... On the basis of introducing the fundamental theory and the basic analysis steps of the sub model method, the strength of the new engine complex assembly structure was analyzed according to the properties of the engine structures, some of the key parts of the engine were analyzed with refined mesh by sub model method and the error of the FEM solution was estimated by the extrapolation method. The example showed that the sub model can not only analyze the comlex structures without the restriction of the software and hardware of the computers, but get the more precise analysis result also. This method is more suitable for the strength analysis of the complex assembly structure. 展开更多
关键词 sub model method ENGINE strength analysis FEM
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CONDITION-BASED MAINTENANCE DECISION MAKING METHODS FOR CIVIL AEROENGINE 被引量:6
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作者 戎翔 左洪福 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2008年第3期201-207,共7页
To provide some feasible condition-based maintenance (CBM) decision making methods for civil aeroengine, firstly, the theory of aeroengine CBM decision making is described. The proportional intensity(PI) model is ... To provide some feasible condition-based maintenance (CBM) decision making methods for civil aeroengine, firstly, the theory of aeroengine CBM decision making is described. The proportional intensity(PI) model is established based on the reliability and condition monitoring data. According to the model, the decision making methods are proposed for the optimal preventive maintenance(PM) interval and removal. Then, the time on wing (TOW) is predicted by collecting actual data based on the engine age and operating conditions. Finally, an example of a fleet for CF6-80C2 engines is illustrated. It shows that sufficient engine operation data are the key of accurate decision making. Results indicate that the CBM decision making methods are helpful for engineers in airlines to control engine maintenance actions and TOW, thus decreasing risks and maintenance costs. 展开更多
关键词 civil aviation aircraft engines maintenance condition-based maintenance proportional intensity model
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Structural Decomposition Analysis on Energy Intensity Changes at Regional Level 被引量:1
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作者 廖华 王策 +1 位作者 朱治双 马晓微 《Transactions of Tianjin University》 EI CAS 2013年第4期287-292,共6页
As China's energy intensity fluctuated in recent years, it is necessary to examine whether this fluctuation happened at a regional level. This paper establishes a decomposition model by using the structural decomp... As China's energy intensity fluctuated in recent years, it is necessary to examine whether this fluctuation happened at a regional level. This paper establishes a decomposition model by using the structural decomposition analysis (SDA) method at a regional level. Then this model is employed to empirically analyze the changes of Beijing's energy intensity. The conclusions are as follows: during 2002-2010, except petroleum, the energy intensity decreased and the changes were mostly attributed to the technology changes, while the final use variation actually increased the energy intensity; comparing different periods of 2002-2010, the decline rates of energy intensity for coal and hydropower were decreasing, resulting from the production technology being more energy-intensive than before; the energy intensity changes of petroleum firstly increased substantially and then decreased moderately. 展开更多
关键词 structural decomposition analysis input-output analysis energy intensity
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Optimization of Output Properties for Bias Signal-Modulated in a Single-Mode Laser
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作者 LI Tai-Quan DONG Ping +1 位作者 YANG Hong-Quan HAN Li-Bo 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第2X期288-292,共5页
Defining the quantity K as the signal-to-noise ratio (SNR) and the normalized intensity fluctuation C(O) of a single-mode laser for bias signal modulation driven by color noises with colored correlation, the whole... Defining the quantity K as the signal-to-noise ratio (SNR) and the normalized intensity fluctuation C(O) of a single-mode laser for bias signal modulation driven by color noises with colored correlation, the whole output properties of the laser system is described by K. It is found that there is a maximum in the curves of K versus D, Q, and io. The optimization parameters are gained. 展开更多
关键词 bias signal modulation correlation noise OPTIMIZATION
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Subspace identification for a stochastic model of plague 被引量:4
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作者 Miao Yu Jianchang Liu 《International Journal of Biomathematics》 2016年第5期85-105,共21页
In this paper, a stochastic model of plague is first studied by subspace identification. First, the discrete model of plague is obtained based on the classical model. The corresponding stochastic model is proposed for... In this paper, a stochastic model of plague is first studied by subspace identification. First, the discrete model of plague is obtained based on the classical model. The corresponding stochastic model is proposed for the existence of stochastic disturbances. Second, for the model, the parameter matrices and noise intensity are obtained. Finally, the simulations of the model show that the subspace identification is more precise than least square method. 展开更多
关键词 Subspace method system identification stochastic biological model PLAGUE
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