The cracks emerged in a fossil-fired power plant in China in 2008 and several similar crack accidents had been detected in nuclear turbines in USA before. The possible causes of the cracks are analyzed in previous stu...
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ISBN:
(纸本)9784883254194
The cracks emerged in a fossil-fired power plant in China in 2008 and several similar crack accidents had been detected in nuclear turbines in USA before. The possible causes of the cracks are analyzed in previous study while the torsional vibration is one of the most significant factors. The paper analyzes the impact of torsional vibration using the practical running data in some turbine generator unit. Based on the transient response analysis under emulational subsynchronous oscillation model simplified from the practical network, the torques acted on the coupling section are analyzed. Then the stress and strain field is calculated for local dangerous point search in Zone of Vulnerability (ZoV) and the fatigue damage criterion determination. Manson-Coffin equation is used to ascertain whether it is high-cycle fatigue or low-cycle fatigue and the fatigue data from standard test specimen is used. The method using local stress and strain analysis as well as fatigue damage cumulation study may establish a novel way to diagnose the crack in an early stage.
This paper presents a method called Event-based Incremental Update of Spatial-Temporal Database. By studying the event-based incremental update of spatial-temporal database, proposed event-based incremental informatio...
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The rollover warning technology reported in this paper focuses on detection of heavy duty truck real-time rollover propensities. The paper suggests a new algorithm of rollover warning for heavy duty vehicle based on K...
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The coolant flow field distribution affects the cooling effect of internal combustion (IC) engine. Simulated calculation is applied in the engine water jacket structure design process more and more because the method ...
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On the basis of self-developed electro-hydraulic variable valve train, controlled auto-ignition (CAI) was achieved under two different EGR strategies on a modified single cylinder engine. Stable CAI operating ranges o...
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On the basis of self-developed electro-hydraulic variable valve train, controlled auto-ignition (CAI) was achieved under two different EGR strategies on a modified single cylinder engine. Stable CAI operating ranges of these two valve timing scenarios were obtained by plotting tested operating points. Within the operating range, engine performances and combustion features were analyzed. The experimental results indicate that operating range of NVO strategy, allowing more substantial adjustment of valve phase, is wider than that of EGRB strategy at fixed engine speed of 1000 r/min. The maximum BMEP of EGRB strategy slightly exceeds the NVO strategy. Moreover, brake thermal efficiency exceeds 30% in most of these two operating range, higher than conventional engine, with an extremely low NOx emission at the same time. Besides, start of combustion of CAI under NVO strategy is a little advanced and combustion duration is a little shorter compare with that of EGRB strategy.
In order to make coordination relation between left wheel and right wheel, a powertrain model based on complete differential dynamic system is established. The freedom of wheel rotation is calculated in the powertrain...
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A nonlinear full-order observer is proposed for vehicle side-slip angle estimation to improve the accuracy and the real-time performance of the side-slip angle estimation. The longitudinal velocity, lateral velocity a...
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A nonlinear full-order observer is proposed for vehicle side-slip angle estimation to improve the accuracy and the real-time performance of the side-slip angle estimation. The longitudinal velocity, lateral velocity and yaw rate of the vehicle are estimated by the observer using the information of vehicle states which are measured by on-board sensors based on the vehicle dynamic model and Uni-Tire model for longitudinal slip and lateral slip, and then, the estimates of the side-slip angle are determined based on the above results. The stability of the observer is analyzed using the theory of input-to-state stability(ISS). The offline estimation result is validated using the vehicle simulation software veDYNA with the parameters of Hongqi CA7180A3E in critical condition;the real-time performance of the full-order nonlinear observer is tested on the simulation platform using the xPC-Target simulation environment and dSPACE real-time system. The simulation results show that the nonlinear estimation method has high estimation precision, good real-time performance and satisfies the requirements of engineering application.
The SEA simulation method to reduce car interior noise in high frequency is introduced by the properties modification of door glass. An SEA (Statistical Energy Analysis) model of a domestic car was built. The inputs o...
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Security evaluation has become a hot topic in the research field of water resource management. In this paper, we established a novel water resource security indicator system based on the Pressure-Status-Response (PSR)...
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ISBN:
(纸本)9788890357411
Security evaluation has become a hot topic in the research field of water resource management. In this paper, we established a novel water resource security indicator system based on the Pressure-Status-Response (PSR) framework using grey relation analysis and technique for order preference by similarity to ideal solution (TOPSIS). A case study of Beijing from 1996 to 2007 was conducted to verify the evaluation system. Results showed that the grey relative closeness degrees of water resource security to the positive ideal solution were low, with the least one of 0.360 in 1999 and largest one of 0.527 in 2007, implying that Beijing was facing severer challenges with water resources during the concerned time. Also, the analysis of water resource security indicated that the pressure of water resource was constantly increasing. Finally, factor analysis was employed to calculate the grey relation degrees of evaluating indices with the ideal solutions so as to reveal the relativity of water resource security of Beijing, which may contribute to a better understanding of the urban water resource management and regulation.
With the increase of the number of electronic control units (ECUs), the integrated and smart control system in automobile is required to solve the problem of information exchange, reliability and maintenance. This pap...
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