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Dynamic modeling and computer simulation analysis of the air spring suspension
Rui Zhou,Bao Zhang,Zhi Li 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.4
In improving the comfort of vehicles, air spring suspension has obvious advantages, but under the action of transient impact load, the damping effect of air spring suspension is not ideal due to the hysteresis phenomenon of air spring stiffness regulation. In order to analyze the mechanism of the above problems, the dynamic mathematical model and simulation model of air spring suspension are established. And the nonlinear characteristic of the elastic characteristics of the suspension is expounded theoretically. The simulation results show that the stiffness of the air spring increases with the increase of the transient impact load, and the peak value of the transfer function increases and moves to high frequency near the natural frequency of the body. And the peak value and the peak frequency of the transfer function only change slightly near the natural frequency of the wheel. There are bifurcations and secondary shocks at the wave crest of the acceleration curve under impact loads of 30 mm and 50 mm. The type of research can provide theoretical basis and reference for the design, analysis and optimization of air suspension.
Rui Zhou,강윤한 한국식품과학회 2018 Food Science and Biotechnology Vol.27 No.6
Thermal stable polysaccharides from Auricularia auricula-judae (AP) have unique molecularstructures and multiple bioactivities. The effects of AP on the physicochemical properties and in vitro starch digestibility of yam starch (YS) were studied. The addition of AP induced a significant increase in the swelling power, solubility, mean volume diameter and adhesiveness as well as a dramatic decrease in the hardness and gumminess (p\0.05). AP showed a strong suppressive effect on in vitro starch digestibility. Higher modulus (G0, G00) and stiffness parameters (Aa), and lower order of relaxation function (a), were observed in oscillatory rheological measurements, indicating that the gels were more elasticlike and had higher pseudoplasticity in the presence of AP. Furthermore, AP remarkably decreased the syneresis and storage modulus (G0), and also retarded the retrogradation process of YS gel at 4C, revealing a synergistic interaction between AP and YS, which could also be demonstrated by scanning electron microscopy.
Rui Liu,Zhang-Long Yu,Yuan-Lin Sun,Li-Tao Tong,Li-Ya Liu,Li-Li Wang,Xian-Rong Zhou,Su-Mei Zhou 한국식품과학회 2021 Food Science and Biotechnology Vol.30 No.6
To investigate the effects of electrolyzed watertreatment on the qualities of rice noodles prepared withsemidry- milled rice flour, pasting properties and thermalproperties of rice flour, and the cooking and texturalproperties of rice noodles were determined. Higher peakviscosity and lower melting enthalpy were observed inelectrolyzed water (EW) treated rice flour. The hardness,gumminess and chewiness of rice noodle in slightly acidicelectrolyzed water treated rice noodles with availablechlorine concentration (ACC) 20.32 mg/L were increasedsignificantly (p\0.05). The cooking loss decreased significantlyin strong acidic electrolyzed water treated noodleswith ACC 10.09 mg/L treatment (p\0.05). Theresults indicated that EW could promote the gelatinizationof rice flour, and improve the textural qualities of ricenoodles. Therefore EW was appropriate to be used in ricenoodle production.
Rui Zhou,Hanlin Liu,Wenhao Yuan,Yanliang Du,Jingmang Xu,Rong Chen 국제구조공학회 2023 Smart Structures and Systems, An International Jou Vol.32 No.2
The temperature prediction approaches of three important locations in an operational longitudinal slab track-bridge structure by using three typical neural network methods based on the field measuring platform of four meteorological factors and internal temperature. The measurement experiment of four meteorological factors (e.g., ambient temperature, solar radiation, wind speed, and humidity) temperature in the three locations of the longitudinal slab and base plate of three important locations (e.g., mid-span, beam end, and Wide-Narrow Joint) were conducted, and then their characteristics were analyzed, respectively. Furthermore, temperature prediction effects of three locations under five various meteorological conditions are tested by using three neural network methods, respectively, including the Artificial Neural Network (ANN), the Long Short-Term Memory (LSTM), and the Convolutional Neural Network (CNN). More importantly, the predicted effects of solar radiation in four meteorological factors could be identified with three indicators (e.g., Root Means Square Error, Mean Absolute Error, Correlation Coefficient of R2). In addition, the LSTM method shows the best performance, while the CNN method has the best prediction effect by only considering a single meteorological factor.
Rui Zhou,Yongxin Yang,Yaojun Ge,Priyan Mendis,Damith Mohotti 한국풍공학회 2015 Wind and Structures, An International Journal (WAS Vol.21 No.2
Open decks are a widely used deck configuration in long-span cable-stayed bridges; however, incorporating aerodynamic countermeasures are advisable to achieve better aerodynamic performance than a bluff body deck alone. A sectional model of an open deck cable-stayed bridge with a main span of 400 m was selected to conduct a series of wind tunnel tests. The influences of five practical aerodynamic countermeasures on flutter and vortex-induced vibration (VIV) performance were investigated and are presented in this paper. The results show that an aerodynamic shape selection procedure can be used to evaluate the flutter stability of decks with respect to different terrain types and structural parameters. In addition, the VIV performance of Π-shaped girders for driving comfortableness and safety requirements were evaluated. Among these aerodynamic countermeasures, apron boards and wind fairings can improve the aerodynamic performance to some extent, while horizontal guide plates with 5% of the total deck width show a significant influence on the flutter stability and VIV. A wind fairing with an angle of 55° showed the best overall control effect but led to more lock-in regions of VIV. The combination of vertical stabilisers and airflow-depressing boards was found to be superior to other countermeasures and effectively boosted aerodynamic performance; specifically, vertical stabilisers significantly contribute to improving flutter stability and suppressing vertical VIV, while airflow-depressing boards are helpful in reducing torsional VIV
Aerodynamic performance evaluation of different cable-stayed bridges with composite decks
Rui Zhou,Yaojun Ge,Yongxin Yang,Yanliang Du,Lihai Zhang 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.34 No.5
The aerodynamic performance of long-span cable-stayed bridges is much dependent on its geometrical configuration and countermeasure strategies. In present study, the aerodynamic performance of three composite cable-stayed bridges with different tower configurations and passive aerodynamic countermeasure strategies is systematically investigated by conducting a series of wind tunnel tests in conjunction with theoretical analysis. The structural characteristics of three composite bridges were firstly introduced, and then their stationary aerodynamic performance and wind-vibration performance (i.e., flutter performance, VIV performance and buffeting responses) were analyzed, respectively. The results show that the bridge with three symmetric towers (i.e., Bridge I) has the lowest natural frequencies among the three bridges, while the bridge with two symmetric towers (i.e., Bridge II) has the highest natural frequencies. Furthermore, the Bridge II has better stationary aerodynamic performance compared to two other bridges due to its relatively large drag force and lift moment coefficients, and the improvement in stationary aerodynamic performance resulting from the application of different countermeasures is limited. In contrast, it demonstrates that the application of both downward vertical central stabilizers (UDVCS) and horizontal guide plates (HGP) could potentially significantly improve the flutter and vortex-induced vibration (VIV) performance of the bridge with two asymmetric towers (i.e., Bridge III), while the combination of vertical interquartile stabilizers (VIS) and airflowdepressing boards (ADB) has the capacity of improving the VIV performance of Bridge II.
Rui Zhou,Hoang Nam Nguyen,Iwao Sasase 한국통신학회 2009 Journal of communications and networks Vol.11 No.5
In this paper, we propose a packet scheduling algorithm for cellular relay networks by considering relay selection, variation of channel quality, and packet delay. In the networks, mobile users are equipped with not only cellular but also user relaying radio interfaces, where base station exploits adaptive high speed downlink channel. Our proposed algorithm selects a user with good cellular channel condition as a relay station for other users with bad cellular channel condition but can get access to relay link with good quality. This can achieve flexible packet scheduling by adjusting transmission rates of cellular link. Packets are scheduled for transmission depending on scheduling indexes which are calculated based on user’s achieved transmission rate, packet utility, and proportional fairness of their throughput. The performance results obtained by using computer simulation show that the proposed scheduling algorithm is able to achieve high network capacity, low packet loss, and good fairness in terms of received throughput of mobile users.
Full-scale test of dampers for stay cable vibration mitigation and improvement measures
Zhou, Haijun,Xiang, Ning,Huang, Xigui,Sun, Limin,Xing, Feng,Zhou, Rui Techno-Press 2018 Structural monitoring and maintenance Vol.5 No.4
This paper reported test of full-scale cables attached with four types of dampers: viscous damper, passive Magneto-Rheological (MR) damper, friction damper and High Damping Rubber (HDR) damper. The logarithmic decrements of the cable with attached dampers were calculated from free vibration time history. The efficiency ratios of the mean damping ratios of the tested four dampers to theoretical maximum damping ratio were derived, which was very important for practical damper design and parameter optimization. Non-ideal factors affecting damper performance were discussed based on the test results. The effects of concentrated mass and negative stiffness were discussed in detail and compared theoretically. Approximate formulations were derived and verified using numerical solutions. The critical values for non-dimensional concentrated mass coefficient and negative stiffness were identified. Efficiency ratios were approximately 0.6, 0.6, and 0.3 for the viscous damper, passive MR damper and HDR damper, respectively. The efficiency ratio for the friction damper was between 0-1.0. The effects of concentrated mass and negative stiffness on cable damping were positive as both could increase damping ratio; the concentrated mass was more effective than negative stiffness for higher vibration modes.
Fractional-order L<sub>β</sub>C<sub>α</sub> Low-Pass Filter Circuit
Zhou, Rui,Zhang, Run-Fan,Chen, Di-Yi The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.4
This paper introduces the fundamentals of the conventional LC low-pass filter circuit in the fractional domain. First, we study the new fundamentals of fractional-order LC low-pass filter circuit including the pure real angular frequency, the pure imaginary angular frequency and the short circuit angular frequency. Moreover, sensitivity analysis of the impedance characteristics and phase characteristics of the LC low-pass filter circuit with respect to the system variables is studied in detail, which shows the greater flexibility of the fractional-order filter circuit in designs. Furthermore, from the filtering property perspective, we systematically investigate the effects of the system variables (LC, frequency f and fractional orders) on the amplitude-frequency characteristics and phase-frequency characteristics. In addition, the detailed analyses of the cut-off frequency and filter factor are presented. Numerical experimental results are presented to verify the theoretical results introduced in this paper.
Rui Zhou,Wei Zhang,Jean W. Zu 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.7
This paper aims to investigate the nonlinear dynamics of a thin-plate workpiece during milling process with cutting force nonlinearities. By modeling the thin-plate workpiece as a cantilevered thin plate and applying the Hamilton’s principle, the equations of motion of thethin-plate workpiece are derived based on the Kirchhoff-plate theory and the von Karman strain-displacement relations. Using the Galerkin’sapproach, the equations of motion are reduced to a two-degree-freedom nonlinear system. The method of Asymptotic Perturbationis utilized to obtain the averaged equations in the case of 1:1 internal resonance and foundational resonance. Numerical methods areused to find the periodic and chaotic oscillations of the cantilevered thin-plate workpiece. The results show that the cantilevered thin-plateworkpiece demonstrate complex dynamic behaviors under time-delay effects, the external and parametric excitations.