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Reliability and Availability Models of Belt drive Systems Considering Failure Dependence

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Chinese Journal of Mechanical Engineering 2019年第2期32卷 133-144页

作者： Peng Gao Liyang Xie Jun Pan School of Mechanical Engineering Liaoning Shihua University School of Mechanical Engineering and Automation Zhejiang Sci-Tech University School of Mechanical Engineering and Automation Northeastern University

Conventional reliability models of belt drive systems in the failure mode of fatigue are mainly based on the static stress strength interference model and its extended models, which cannot consider dynamic factors in the operational duration and be used for further availability analysis. In this paper, time-dependent reliability models, failure rate models and availability models of belt drive systems are developed based on the system dynamic equations with the dynamic stress and the material property degradation taken into account. In the proposed models, dynamic failure dependence and imperfect maintenance are taken into consideration. Furthermore, the issue of time scale inconsistency between system failure rate and system availability is proposed and addressed in the proposed system availability models. Besides, Monte Carlo simulations are carried out to validate the established models. The results from the proposed models and those from the Monte Carlo simulations show a consistency. Furthermore, the case studies show that the failure dependence, imperfect maintenance and the time scale inconsistency have significant influences on system availability. The independence assumption about the belt drive systems results in underestimations of both reliability and availability. Moreover, the neglect of the time scale inconsistency causes the underestimate of the system availability. Meanwhile, these influences show obvious time-dependent characteristics.

关键词： Availability Reliability Belt drive Failure dependence Time scale inconsistency

Dynamics of rolling mill drive system considering arc tooth gear dynamic characteristics

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Journal of Iron and Steel Research International 2019年第9期26卷 953-961页

作者： Ming Zhang Yan Peng Jian-liang Sun Hao-ran Li College of Mechanical and Equipment Engineering Hebei University of EngineeringHandan 056038HebeiChina National Engineering Research Center for Equipment and Technology of Cold Strip Rolling Yanshan UniversityQinhuangdao 066004HebeiChina

The arc tooth gear spindle (ATGS) is the key structure of the drive system of hot finishing rolling mills. To investigate the dynamic characteristics of ATGS of the drive system of hot finishing rolling mills, a dynamic mechanical model of ATGS was established. The influences of dynamic displacement and dynamic torque on dynamic load (meshing force, additional torque and friction torque) were studied during the non-steady-state operation of ATGS. On this basis, a dynamic model of rolling mill drive system was established considering the arc tooth gear dynamic characteristics. The dynamic response of the drive system was simulated and analyzed. The results showed that the nonlinear characteristics of ATGS were obvious;the meshing force (PX and PZ) could restrain the increase in dynamic displacement, which reflected the positive stiffness of ATGS;there was a coupling among the vertical, horizontal and torsional directions in the drive system model considering the dynamic characteristics of the arc tooth gear;the vibration intensity of ATGS in the horizontal direction is greater than that in the vertical direction when the self-excited torsional vibration happens;the greater the axial inclination angle was, the more complex the vibration mode was, and the lower the stability of the drive system was.

关键词： Rolling mill drive system Arc tooth gear Coupling model Dynamic characteristics

Evaluation of electron cyclotron current drive performance for CFETR

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Plasma Science and Technology 2019年第6期21卷 63-71页

作者： Wei WEI Xiaojie WANG Miaohui LI Bojiang DING Hefei University of Technology Hefei 230601 People's Republic of China Institute of Plasma Physics Chinese Academy of Sciences Hefei 230031 People's Republic of China

A number of simulations of electron cyclotron current drive (ECCD) have been carried out for the China Fusion Engineering Test Reactor (CFETR) using the C3PO/LUKE code to investigate the performance and optimize schemes of power injection for the design of the *** operation ranges of the toroidal field,cutoff density,and resonance layer location are given at different source frequencies in CFETR phases Ⅰ and Ⅱ.A comparison of ECCD performance between the horizontal and top port launch is *** efficiency (γEC) estimated for CFETR phase Ⅰ is γEC =0.21 for top port launch and γEC =0.20 for horizontal port *** ECCD efficiency and second-harmonic absorption is calculated at different wave frequencies (from 170 to 230 GHz) in CFETR phase Ⅱ.It is found that the highest driven efficiency is obtained at 210 GHz with the toroidal field of 6.5 T,and the second-harmonic absorption increases rapidly with the increase of frequency.

关键词： CFETR electron cyclotron current drive current drive efficiency

ROCO:Using a Solid State drive Cache to Improve the Performance of a Host-Aware Shingled Magnetic Recording drive

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Journal of Computer Science & Technology 2019年第1期34卷 61-76页

作者： Wen-Guo Liu Ling-Fang Zeng Dan Feng Kenneth B.Kent School of Computer Science and Technology Huazhong University of Science and TechnologyWuhan 430074China Faculty of Computer Science University of New BrunswickFrederictonE3B 5A3Canada

Shingled magnetic recording (SMR)can effectively increase the capacity of hard disk drives (HDDs).Hostaware SMR (HA-SMR)is expected to be more popular than other SMR models because of its backward compatibility and new SMR-specific ***,an HA-SMR drive often suffers performance degradation under write-intensive workloads because of frequent non-sequential writes buffered in the disk *** non-sequential writes mainly come from update writes,small random writes and out-of-order *** this paper,we propose a hybrid storage system called ROCO which aims to use a solid state drive (SSD)cache to improve the performance of an HA-SMR *** reorders out-of-order writes belonging to the same zone and uses the SSD cache to absorb update writes and small random *** also design a data replacement algorithm called CREA for the SSD *** first conducts zone-oriented hot/cold data identification to identify cold-cached zones and hot-cached zones,and then evicts data blocks belonging to colder zones with higher priorities that can be sequentially written or written through host-side read-modify-write *** gives the lowest priority to data blocks belonging to the hottest-cached zone that have to be non-sequentially *** results show that ROCO can effectively reduce non-sequential writes to the HA-SMR drive and improve the performance of the HA-SMR drive.

关键词： solid state reordering zone-oriented drive (SSD)cache host-aware shingled magnetic recording (HA-SMR)drive zone-oriented block hot/cold data identification data replacement algorithm

Successive Picket drive for Mitigating the Ablative Richtmyer–Meshkov Instability

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Chinese Physics Letters 2019年第2期36卷 28-31页

作者： Meng Li Wen-Hua Ye Institute of Applied Physics and Computational Mathematics Center for Applied Physics and Technology HEDPS Peking University

The ablative Richtmyer–Meshkov instability(ARMI) is crucial to the successful ignition implosion of the inertial confinement fusion(ICF) because of its action as the seed of the Rayleigh–Taylor instability. In usual ICF implosions, the first shock driven by various foots of the pulses plays a central role in the ARMI growth. We propose a new scheme for refraining from ARMI with a pulse of successive pickets. With the successive-picket pulse design, a rippled capsule surface is compressed by three successive shocks with sequentially strengthening intensities and ablated stabilization, and the ablative Richtmyer–Meshkov growth is mitigated quite *** numerical simulations and theoretical analyses identify the validity of this scheme.

关键词： RMI ICF Successive Picket drive for Mitigating the Ablative Richtmyer Meshkov Instability

Effect of front guide nozzle shape on the flow characteristics in an augmentation channel of a direct drive turbine for wave power generation

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Science China(Technological Sciences) 2010年第1期53卷 46-51页

作者： Deepak PRASAD Mohammed Asid ZULLAH Mohammed Rafiuddin AHMED Young-Ho LEE Graduate School Korea Maritime University1 Dongsam-dong Youngdo-kuBusan606-791Republic of Korea Division of Mechanical Engineering University of the South PacificPrivate Mail BagLaucala CampusSuvaFiji Islands Division of Mechanical & Information Engineering Korea Maritime University1 Dongsam-dong Youngdo-kuBusan606-791Republic of Korea

There is an increasing interest in cross flow turbines(also known as Banki turbines) for small and low head applications because of their simple structure as well as low capital and maintenance *** present work aims at implementing the direct drive turbine(DDT) of cross flow type for wave power generation.A numerical wave tank was used to simulate the waves and after obtaining the desired wave properties;the augmentation channel plus the front guide nozzle and rear chamber were integrated to the numerical wave *** waves in the numerical wave tank were generated by a piston type wave maker which was located at the wave tank *** inlet which was modeled as a plate wall moved sinusoidally with the general function x = asinω *** augmentation channel consisted of a front nozzle,rear nozzle and an internal fluid region which represented the turbine *** front and rear nozzles were geometrically the *** different front guide nozzle configurations were studied:a standard guide nozzle which was originally attached to the augmentation channel and two other front guide nozzles of different *** purpose of this study is to observe how the front guide nozzle shape influences the flow downstream,mainly in the augmenta-tion channel,water power and the first stage energy *** analysis was performed using a commercial CFD code *** results of the flow in the augmentation channel for the three front guide nozzles are presented in this paper.

关键词： numerical wave tank wave power augmentation channel direct drive turbine water power

Active Design Method of Tooth Profiles for Cycloid drive Based on Meshing Efficiency

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Transactions of Nanjing University of Aeronautics and Astronautics 2019年第3期36卷 413-423页

作者： WANG Jian SU Deyu School of Mechanical Engineering Nanjing Institute of TechnologyNanjing 211167P.R.China Institute of Intelligent Manufacturing Huazhong University of Science and Technology in QuanzhouQuanzhou 362300P.R.China

An active design method of tooth profiles for cycloid gears based on their meshing efficiency is *** method takes the meshing efficiency as one of the design variables to determine the tooth *** calculation method for the meshing efficiency of planetary transmission is analyzed and the equation of the meshing efficiency is *** between the meshing efficiency,the radius of the pin wheel and the eccentric distance are *** design constraint quations and the strength constraint quations are *** the basis of this,a design procedure is laid *** examples using different input parameters are conducted to demonstrate the feasibility of the approach.A dynamic simulation of the rigid flexible coupling of cycloid gears is also *** results show that the proposed design method is more flexible to control the tooth profiles by changing the input values of the transmission efficiency.

关键词： cycloid drive tooth profile active design meshing efficiency meshing theory

DYNAMICS OF THE LOOPER drive MECHANISM ON A BLIND STITCHING MACHINE

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Journal of China Textile University(English Edition) 1990年第4期8卷 54-62页

作者：项靖安史荣生 Basic Sciences Department

The looper drive mechanism is a main moving part in the blind stitching machine, which is aspatial 5 bar RRRSR linkage. In this paper, a dynamic analysis of the looper drive mechanism is made by means of the ma-trix method. Two methods are adopted in the calculation of the shaking force and shaking moment, one isdone by the constraint reaction of the flame-connected kinematic parts; the other is the inertialforces of all moving links.

关键词： blind stitching machine looper drive mechanism shaking force shaking moment constraint reaction

Fuzzy fault tree analysis of roller oscillating tooth gear drive

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Journal of Harbin Institute of Technology(New Series) 2002年第3期9卷 249-253页

作者： LI Guixian(李瑰贤) YANG Weijun(杨伟君) ZHANG Xin(张欣) LI Xiao(李笑) LIU Fuli(刘福利) Dept. of Mechanical Engineering and Automatization Harbin Institute of Technology Harbin 150001 China Dept. of Mechanical Engineering and Automatization Harbin Institute of Technology Harbin 150001 China University of Arkansas USA Dept. of Mechanical Engineering and Automatization Harbin Institute of Technology Harbin 150001 China Dept. of Mechanical Engineering and Automatization Harbin Institute of Technology Harbin 150001 China

Conventional fault tree and reliability analysis do not reflect the characteristics of basic events as non stationary and ergodic process. To overcome these drawbacks, theory of fuzzy sets is employed to run fault tree analysis(FTA) of roller oscillating tooth gear drive(ROTGD), the relative frequencies of basic events are considered as symmetrical normal fuzzy numbers, from the logical relationship between different events in the fault tree and fuzzy operators AND and OR, fuzzy probability of top event is solved. Finally, an example is given to demonstrate a real ROTGD system.

关键词： roller oscillating tooth gear drive fuzzy fault tree non-stationary probability of event