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Model reduction techniques for dynamics analysis of ultra-precision linear stage

Xuedong CHEN, Zhixin LI

《机械工程前沿（英文）》 2009年 第4卷 第1期   页码 64-70 doi: 10.1007/s11465-009-0009-x

摘要： Spring-damping elements are used to simplify the internal interaction in the proposed finite element (FE) model of an ultra-precision linear stage. The dynamics behavior is studied. The comparison between mode shapes from the eigenvalue analysis shows that the components, except the translator, can represent system dynamics characteristics. A reduction approach is used to simplify the system in a dynamic studied. There is little difference between the vibration mode and the response analysis. The experimental modal analysis proves the validity of the reduction approach, which can be generalized to the development and dynamics characteristic study of a complex system model to obviously save computational resource.

关键词： dynamics analysis     air-bearing     linear stage     reduction    

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Nonlinear dynamics and analysis of a four-bar linkage with clearance

Yuanguang TANG, Zongyu CHANG, Xiaogang DONG, Yafei HU, Zhenjiang YU

《机械工程前沿（英文）》 2013年 第8卷 第2期   页码 160-168 doi: 10.1007/s11465-013-0258-6

摘要：

In this paper, nonlinear dynamic behavior of a four-bar linkage considering clearance is studied. The dynamic model of the linkage with a clearance between coupler and rocker is developed firstly. Then the dynamic equations of this mechanism are solved by a numerical method. According to the calculated response, compliance, force and trajectory of pin in joint bearing are obtained. Effects of clearance magnitude and the relationship between a mechanism with clearance and without clearance are studied. By using Poincare Map, it is proved that strange attractors or chaos exist in the dynamic response. In addition, phenomena of chaos, periodic response and subharmonic response also can be found in the special condition. Bifurcation diagram is used to suggest that bifurcation and fractal phenomena exist in the dynamic response of this mechanism.

关键词： four-bar linkage     chaos     bifurcation     strange attractors     dynamics    

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Modeling and analysis of landing collision dynamics for a shipborne helicopter

Dingxuan ZHAO, Haojie YANG, Carbone GIUSEPPE, Wenhang LI, Tao NI, Shuangji YAO

《机械工程前沿（英文）》 2021年 第16卷 第1期   页码 151-162 doi: 10.1007/s11465-020-0617-z

摘要： A Lagrange dynamic model is established based on small-angle approximation to improve the simulation model for shipborne helicopter landing collision. To describe fuselage motion effectively, the proposed model considers ship motion, the interaction of the tires with the deck, and tire slippage. A mechanism of sliding motion is built, and a real-time reliability analysis of the algorithm is implemented to validate the proposed model. Numerical simulations are also conducted under different operation conditions. Results show that the proposed dynamic model can simulate the collision motion of helicopter landing in real time. Several suggestions for helicopter pilot landing are likewise provided.

关键词： shipborne helicopter     landing model     Lagrange equations     dynamics     validation    

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Dynamics analysis of bladder-urethra system based on CFD

Qinghua JIN, Xiaojun ZHANG, Xiaoyang LI, Jianliu WANG,

《机械工程前沿（英文）》 2010年 第5卷 第3期   页码 336-340 doi: 10.1007/s11465-010-0027-8

摘要： A mathematical model for a bladder-urethra system can provide basic analysis for the disabled urethra closure of stress urinary incontinence (SUI) patients in a clinic. Based on computational fluid dynamics (CFD), we developed a three-dimensional urodynamic bladder-urethra system, which includes bladder, bladder neck, prostate, and urethra. The realistic recirculation process of the urinary bladder during the physiologic voiding process in conjunction with a flow simulation through the female urinary bladder and urethra is presented. The computational results show that a dead-water zone and the zone of secondary flow occur, independent of the shape of the prostatic urethra. For the pathological prostata, the extreme constriction of the prostatic urethra results in an additional wide-stretched dead-water zone. The simulation results does not only improve urinary incontinence surgery for clinicians, but can also provide a basis for theoretical analysis.

关键词： bladder-urethra system     stress urinary incontinence (SUI)     computational fluid dynamics (CFD)     urodynamics    

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Design and analysis of linear oscillating motor for linear pump application-magnetic field, dynamics

Zongxia JIAO,Tianyi WANG,Liang YAN

《机械工程前沿（英文）》 2016年 第11卷 第4期   页码 351-362 doi: 10.1007/s11465-016-0407-9

摘要：

A linear oscillating motor is an electromagnetic actuator that can achieve short-stroke reciprocating movement directly without auxiliary transmission mechanisms. It has been widely used in linear pump applications as the source of power and motion. However, because of the demand of high power density in a linear actuation system, the performance of linear oscillating motors has been the focus of studies and deserves further research for high power density. In this paper, a general framework of linear oscillating motor design and optimization is addressed in detail, including the electromagnetic, dynamics, and thermal aspects. First, the electromagnetic and dynamics characteristics are modeled to reveal the principle for optimization. Then, optimization and analysis on magnetic structure, resonant system, and thermal features are conducted, which provide the foundation for prototype development. Finally, experimental results are provided for validation. As a whole, this process offers complete guidance for high power density linear oscillating motors in linear pump applications.

关键词： linear oscillating motor     linear pump     magnetic field     motor optimization    

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Theory analysis and system identification methods on thermal dynamics characteristics of ballscrews

XIA Junyong, HU Youmin, WU Bo, SHI Tielin

《机械工程前沿（英文）》 2008年 第3卷 第4期   页码 408-415 doi: 10.1007/s11465-008-0061-y

摘要： Empirical model of machine tools on thermal error has been widely researched, which can compensate for thermal error to some extent but not suitable for thermal dynamic errors produced by dynamic heat sources. The thermoelastic phenomenon of unidimensional heat transfer of ballscrews influenced by changeable heat sources is analyzed based on the theory of heat transfer. Two methods for system identification (the least square system identification and BP artificial neural network (ANN) system identification) are put forward to establish a dynamic characteristic model of thermal deformation of ballscrews. The model of thermal error of the axis in a feed system of DM4600 vertical miller is established with a fine identification effect. Comparing the results of the two identification methods, the BP ANN system identification is more precise than the least square system identification.

关键词： square system     network     vertical miller     transfer     ANN    

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Real time monitoring for analysis of dam stability: Potential of nonlinear elasticity and nonlinear dynamics

T. CHELIDZE, T. MATCHARASHVILI, V. ABASHIDZE, M. KALABEGISHVILI, N. ZHUKOVA

《结构与土木工程前沿（英文）》 2013年 第7卷 第2期   页码 188-205 doi: 10.1007/s11709-013-0199-5

摘要： Large dams are complex structures with nonlinear dynamic behavior. Engineers often are forced to assess dam safety based on the available incomplete data, which is extremely difficult. This important problem can be solved with the modern theory of complex systems. It is possible to derive characteristics of the whole unknown dynamics of a structure using few data sets of certain carefully selected representative parameter(s). By means of high quality continuous records of some geotechnical characteristic(s) of a dam and modern methods of time series linear/nonlinear analysis the main dynamical features of the entire, unknown process (here—dam deformation) can be analyzed. ?We created the cost-effective Monitoring Telemetric System for Dam Diagnostics (DAMWATCH), which consists of sensors (tiltmeters), terminal and central controllers connected by the GSM/GPRS Modem to the diagnostic center. The tilt data recorded for varying reservoir level are compared with static design model of dam deformations computed by a finite element method (FEM) for the dam-reservoir-foundation system. Besides, recently developed linear/nonlinear data analysis and prediction schemes may help to quantify fine dynamical features of the dam behavior. The software package DAMTOOL has been developed for this purpose. ?The differences between measured and theoretically predicted response parameters of the dam may signal abnormal behavior of the object. The data obtained already by testing of the DAMWATCH/DAMTOOL system during operation of the high Enguri arc dam and reservoir (Georgia) show interesting long-term and short-term patterns of tilts in the dam body, which can be used for dam diagnostics. The proposed real-time telemetric monitoring (DAMWATCH) complex and linear/nonlinear dynamical analysis system (DAMTOOL) are unique.

关键词： real time monitoring     telemetry     dam tilts     diagnostic tools     hysteresis     nonlinear dynamics    

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Fictitious soil pile model for dynamic analysis of pipe piles under high-strain conditions

《结构与土木工程前沿（英文）》   页码 915-934 doi: 10.1007/s11709-023-0907-8

摘要： A fictitious soil pile (FSP) model is developed to simulate the behavior of pipe piles with soil plugs undergoing high-strain dynamic impact loading. The developed model simulates the base soil with a fictitious hollow pile fully filled with a soil plug extending at a cone angle from the pile toe to the bedrock. The friction on the outside and inside of the pile walls is distinguished using different shaft models, and the propagation of stress waves in the base soil and soil plug is considered. The motions of the pile−soil system are solved by discretizing them into spring-mass model based on the finite difference method. Comparisons of the predictions of the proposed model and conventional numerical models, as well as measurements for pipe piles in field tests subjected to impact loading, validate the accuracy of the proposed model. A parametric analysis is conducted to illustrate the influence of the model parameters on the pile dynamic response. Finally, the effective length of the FSP is proposed to approximate the affected soil zone below the pipe pile toe, and some guidance is provided for the selection of the model parameters.

关键词： fictitious soil pile     soil plug     pipe piles     high-strain dynamic analysis     one-dimensional wave theory     pile dynamics    

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Flow, thermal, and vibration analysis using three dimensional finite element analysis for a flux reversal

B. VIDHYA,K. N. SRINIVAS

《能源前沿（英文）》 2016年 第10卷 第4期   页码 424-440 doi: 10.1007/s11708-016-0423-9

摘要： This paper presents the simulation of major mechanical properties of a flux reversal generator (FRG) viz., computational fluid dynamic (CFD), thermal, and vibration. A three-dimensional finite element analysis (FEA) based CFD technique for finding the spread of pressure and air velocity in air regions of the FRG is described. The results of CFD are mainly obtained to fine tune the thermal analysis. Thus, in this focus, a flow analysis assisted thermal analysis is presented to predict the steady state temperature distribution inside FRG. The heat transfer coefficient of all the heat producing inner walls of the machine are evaluated from CFD analysis, which forms the main factor for the prediction of accurate heat distribution. The vibration analysis is illustrated. Major vibration sources such as mechanical, magnetic and applied loads are covered elaborately which consists of a 3D modal analysis to find the natural frequency of FRG, a 3D static stress analysis to predict the deformation of the stator, rotor and shaft for different speeds, and an unbalanced rotor harmonic analysis to find eccentricity of rotor to make sure that the vibration of the rotor is within the acceptable limits. Harmonic analysis such as sine sweep analysis to identify the range of speeds causing high vibrations and steady state vibration at a mode frequency of 1500 Hz is presented. The vibration analysis investigates the vibration of the FRG as a whole, which forms the contribution of this paper in the FRG literature.

关键词： flux reversal generator     air velocity     computation fluid dynamics     thermal analysis     vibration analysis     finite element analysis    

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Design and analysis of a new high frequency double-servo direct drive rotary valve

Muzhi ZHU,Shengdun ZHAO,Jingxiang LI

《机械工程前沿（英文）》 2016年 第11卷 第4期   页码 344-350 doi: 10.1007/s11465-016-0406-x

摘要：

Researchers have investigated direct drive valve for many years to solve problems, such as fluid force imbalance and switching frequency. The structure of the rotary valve has received considerable research interest because of its favorable dynamic properties and simple structure. This paper studied the high frequency double-servo direct drive rotary valve (DDRV), and proposed a novel structure and drive method satisfying high reversing frequency and adequate quantity of flow. Servo motors are integrated into the valve by the innovative structure, which is designed to equilibrate the unbalanced radial fluid force with the symmetric distributed oil ports. Aside from the fast reversing function of the valve, the DDRV presented high performance in linearity of the flow quantity and valve opening as a result of the fan-shaped flow ports. In addition, a computational fluid dynamics (CFD) method based on Fluent was conducted to verify the flux regulation effect of the height change of the adjustable boss.

关键词： direct drive rotary valve     computational fluid dynamics (CFD)     flow regulation    

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Nonlinear dynamic analysis for elastic robotic arms

M. H. KORAYEM, H. N. RAHIMI

《机械工程前沿（英文）》 2011年 第6卷 第2期   页码 219-228 doi: 10.1007/s11465-011-0218-y

摘要：

The aim of the paper is to analyze the nonlinear dynamics of robotic arms with elastic links and joints. The main contribution of the paper is the comparative assessment of assumed modes and finite element methods as more convenient approaches for computing the nonlinear dynamic of robotic systems. Numerical simulations comprising both methods are carried out and results are discussed. Hence, advantages and disadvantages of each method are illustrated. Then, adding the joint flexibility to the system is dealt with and the obtained model is demonstrated. Finally, a brief description of the optimal motion generation is presented and the simulation is carried out to investigate the role of robot dynamic modeling in the control of robots.

关键词： robotic arms     elastic link     elastic joint     nonlinear dynamics     optimal control    

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Pressure drop analysis on the positive half-cell of a cerium redox flow battery using computational fluiddynamics: Mathematical and modelling aspects of porous media

Fernando F. Rivera, Berenice Miranda-Alcántara, Germán Orozco, Carlos Ponce de León, Luis F. Arenas

《化学科学与工程前沿（英文）》 2021年 第15卷 第2期   页码 399-409 doi: 10.1007/s11705-020-1934-9

摘要： Description of electrolyte fluid dynamics in the electrode compartments by mathematical models can be a powerful tool in the development of redox flow batteries (RFBs) and other electrochemical reactors. In order to determine their predictive capability, turbulent Reynolds-averaged Navier-Stokes (RANS) and free flow plus porous media (Brinkman) models were applied to compute local fluid velocities taking place in a rectangular channel electrochemical flow cell used as the positive half-cell of a cerium-based RFB for laboratory studies. Two different platinized titanium electrodes were considered, a plate plus a turbulence promoter and an expanded metal mesh. Calculated pressure drop was validated against experimental data obtained with typical cerium electrolytes. It was found that the pressure drop values were better described by the RANS approach, whereas the validity of Brinkman equations was strongly dependent on porosity and permeability values of the porous media.

关键词： CFD simulation     porous media     porous electrode     pressure drop     redox flow battery    

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Computational fluid dynamics simulation of aerosol transport and deposition

Yingjie TANG, Bing GUO

《环境科学与工程前沿（英文）》 2011年 第5卷 第3期   页码 362-377 doi: 10.1007/s11783-011-0365-8

摘要： In this article computational fluid dynamics (CFD) simulation of aerosol transport and deposition, i.e. the transport and deposition of particles in an aerosol, is reviewed. The review gives a brief account of the basics of aerosol mechanics, followed by a description of the general CFD approach for flow field simulation, turbulence modeling, wall treatments and simulation of particle motion and deposition. Then examples from the literature are presented, including CFD simulation of particle deposition in human respiratory tract and particle deposition in aerosol devices. CFD simulation of particle transport and deposition may provide information that is difficult to obtain through physical experiments, and it may help reduce the number of experiments needed for device design. Due to the difficulty of describing turbulent flow and particle-eddy interaction, turbulent dispersion of particles remains one of the greatest challenges for CFD simulation. However, it is possible to take a balanced approach toward quantitative description of aerosol dispersion using CFD simulation in conjunction with empirical relations.

关键词： computational fluid dynamics (CFD)     aerosol     transport     deposition    

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Microbial community structure and dynamics of starch-fed and glucose-fed chemostats during two years

Min GOU,Jing ZENG,Huizhong WANG,Yueqin TANG,Toru SHIGEMATSU,Shigeru MORIMURA,Kenji KIDA

《环境科学与工程前沿（英文）》 2016年 第10卷 第2期   页码 368-380 doi: 10.1007/s11783-015-0815-9

摘要： The microbial community structures of two mesophilic anaerobic chemostats, one fed with glucose, the other with starch as sole carbon sources, were studied at various dilution rates (0.05–0.25 d for glucose and 0.025–0.1 d for starch) during two years continuous operation. In the glucose-fed chemostat, the aceticlastic methanogen spp. and hydrogenotrophic methanogen spp. predominated at low dilution rates, whereas spp. and the hydrogenotrophic spp. predominated together when dilution rates were greater than 0.1 d . Bacteria affiliated with the phyla Bacteroidetes, Spirochaetes, and Actinobacteria predominated at dilution rates of 0.05, 0.1, and 0.15 d , respectively, while Firmicutes predominated at higher dilution rates (0.2 and 0.25 d ). In the starch-fed chemostat, the aceticlastic and hydrogenotrophic methanogens coexisted at all dilution rates. Although bacteria belonging to only two phyla were mainly responsible for starch degradation (Spirochaetes at the dilution rate of 0.08 d and Firmicutes at other dilution rates), different bacterial genera were identified at different dilution rates. With the exception of Archaea in the glucose-fed chemostat, the band patterns revealed by denaturing gradient gel electrophoresis (DGGE) of the microbial communities in the two chemostats displayed marked changes during long-term operation at a constant dilution rate. The bacterial community changed with changes in the dilution rate, and was erratic during long-term operation in both glucose-fed and starch-fed chemostats.

关键词： microbial community     glucose degradation     starch degradation     dilution rate     continuous methane fermentation     phylogenetic analysis    

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Recent developments in passive interconnected vehicle suspension

Wade A. SMITH, Nong ZHANG,

《机械工程前沿（英文）》 2010年 第5卷 第1期   页码 1-18 doi: 10.1007/s11465-009-0092-z

摘要： This paper presents an overall review on the historical concept development and research advancement of passive hydraulically interconnected suspension (HIS) systems. It starts with an introduction to passive HIS systems and their various incarnations developed over many decades. Next, a description is provided of a recently proposed multidisciplinary approach for the frequency-domain analysis of vehicles fitted with an HIS. The experimental validation and applications of the method to both free and forced vibration analysis are discussed based on a simplified, roll-plane half-car model. A finite-element-method-based approddach for modelling the transient dynamics of an HIS vehicle is also briefly outlined. In addition, recent work on the investigation of NVH associated with HIS-equipped vehicles is mentioned. Discussion is then provided on future work to the further understanding of HIS and its applications. The paper concludes that interconnected suspension schemes can provide much greater flexibility to independently specify modal stiffness and damping parameters – a characteristic unique among passive suspensions. It points out that there is a need for system optimisation, and there are troublesome NVH issues that require solutions. It suggests that further research attention and effort be paid to NVH issues and system level optimisation to gain a greater understanding of HIS and to broaden its applications.

关键词： interconnected suspensions     rollover prevention     vehicle dynamics     ride comfort     multibody system dynamics     hydraulic system dynamics    

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标题 作者 时间 类型 操作

Model reduction techniques for dynamics analysis of ultra-precision linear stage

Xuedong CHEN, Zhixin LI

期刊论文

Nonlinear dynamics and analysis of a four-bar linkage with clearance

Yuanguang TANG, Zongyu CHANG, Xiaogang DONG, Yafei HU, Zhenjiang YU

期刊论文

Modeling and analysis of landing collision dynamics for a shipborne helicopter

Dingxuan ZHAO, Haojie YANG, Carbone GIUSEPPE, Wenhang LI, Tao NI, Shuangji YAO

期刊论文

Dynamics analysis of bladder-urethra system based on CFD

Qinghua JIN, Xiaojun ZHANG, Xiaoyang LI, Jianliu WANG,

期刊论文

Design and analysis of linear oscillating motor for linear pump application-magnetic field, dynamics

Zongxia JIAO,Tianyi WANG,Liang YAN

期刊论文

Theory analysis and system identification methods on thermal dynamics characteristics of ballscrews

XIA Junyong, HU Youmin, WU Bo, SHI Tielin

期刊论文

Real time monitoring for analysis of dam stability: Potential of nonlinear elasticity and nonlinear dynamics

T. CHELIDZE, T. MATCHARASHVILI, V. ABASHIDZE, M. KALABEGISHVILI, N. ZHUKOVA

期刊论文

Fictitious soil pile model for dynamic analysis of pipe piles under high-strain conditions

期刊论文

Flow, thermal, and vibration analysis using three dimensional finite element analysis for a flux reversal

B. VIDHYA,K. N. SRINIVAS

期刊论文

Design and analysis of a new high frequency double-servo direct drive rotary valve

Muzhi ZHU,Shengdun ZHAO,Jingxiang LI

期刊论文

Nonlinear dynamic analysis for elastic robotic arms

M. H. KORAYEM, H. N. RAHIMI

期刊论文

Pressure drop analysis on the positive half-cell of a cerium redox flow battery using computational fluiddynamics: Mathematical and modelling aspects of porous media

Fernando F. Rivera, Berenice Miranda-Alcántara, Germán Orozco, Carlos Ponce de León, Luis F. Arenas

期刊论文

Computational fluid dynamics simulation of aerosol transport and deposition

Yingjie TANG, Bing GUO

期刊论文

Microbial community structure and dynamics of starch-fed and glucose-fed chemostats during two years

Min GOU,Jing ZENG,Huizhong WANG,Yueqin TANG,Toru SHIGEMATSU,Shigeru MORIMURA,Kenji KIDA

期刊论文

Recent developments in passive interconnected vehicle suspension

Wade A. SMITH, Nong ZHANG,

期刊论文