scholarly journals STUDY ON FORCE MECHANISM OF CABLE-TRUSS FRAME AND JUMPED LAYOUT OF ANNULAR CROSSED CABLE-TRUSS STRUCTURE

2021 ◽  
Keyword(s):  
Dynamic Performance ◽  
Truss Structure ◽  
Optimal Order ◽  
Initial Stiffness ◽  
Steel Consumption ◽  
Dynamic Performances ◽  
New Type ◽  
Original Scheme ◽  
Force Mechanism ◽  
Tension Structure

A new type of cable-strut tension structure named Annular Crossed Cable-truss Structure(ACCTS) comprises a series of planar cable-truss frames crossed each other. To investigate the force mechanism of ACCTS, a cable-truss frame model with 2-bar and 6-cable has been developed, and its initial stiffness formula has been derived as well. The model is further simplified to make it is upper and lower vector heights equal, and then the initial stiffness formula and the critical slack load formula are further deduced. Based on ANSYS software and cable-truss frame with a span of 60m, the influences of the number of struts and position of jumped layout on the cable-truss frame are studied. According to the former 60m span cable-truss frame's research results, the jumped layout of ACCTS with a span of 100m is studied. The static and dynamic performances of two schemes, the optimal jumped layout scheme and the original scheme, are systematically studied. It is shown that the number of struts would be about 6~8 for the planar cable-truss frame and the optimal order of jumped layout is strut 6-7→strut 4-5→strut 2-3. The optimal order of jumped layout of ACCTS agrees with that of the cable-truss frame, verifying the feasibility of conclusions. In the condition of no variation in the original structure's static and dynamic performance, the optimal scheme of the jumped layout will lower the steel consumption and enhance the buckling loads. Moreover, it also simplifies structure for easy construction.

Optimization Design Based on Static and Dynamic Performance of Beam

2011 ◽  
Vol 188 ◽  
pp. 743-749
Author(s):  
M. Cong ◽  
Q. Zhao ◽  
T. Han ◽  
D.D. Liu ◽  
Z.B. Duan ◽  
...  
Keyword(s):  
High Speed ◽  
Optimization Design ◽  
Dynamic Performance ◽  
Optimization Method ◽  
Improve Performance ◽  
Sizing Optimization ◽  
Machining Center ◽  
Before And After ◽  
Dynamic Performances ◽  
New Type

A new type of high speed vertical machining center which adopt gantry type structure is introduced. In order to improve performance of Beam, a sizing optimization based on static and dynamic performance is carried out. And a comparison is made between the analysis results before and after optimization. It is proved that the optimization method is feasible and both static and dynamic performances are improved.

Comparison on General Track Spectrum for Chinese Main Railway Lines and Track Spectrum of American Railway Lines

2011 ◽  
Vol 250-253 ◽  
pp. 3822-3826 ◽  
Author(s):  
Xian Mai Chen ◽  
Xia Xin Tao ◽  
Gao Hang Cui ◽  
Fu Tong Wang
Keyword(s):  
Dynamic Performance ◽  
Dynamic Responses ◽  
Wave Band ◽  
Wheel Load ◽  
Railway Line ◽  
Acceleration Rate ◽  
Time Histories ◽  
Railway System ◽  
Dynamic Performances ◽  
Track Irregularity

The general track spectrum of Chinese main railway lines (ChinaRLS) and the track spectrum of American railway lines (AmericaRLS) are compared in terms of character of frequency domain, statistical property of time domain samples and dynamic performance. That the wavelength range of the ChinaRLS, which is characterized by the three levels according to the class of railway line, is less than AmericaRLS at common wave band of 1~50m is calculated. Simultaneously, the mean square values of two kinds of track spectra are provided at the detrimental wave bands of 5~10m, 10~20m, and so on. The time-histories of ChinaRLS and AmericaRLS are simulated according to the trigonometric method, and the digital statistical nature of simulated time samples is analyzed. With inputting the two kinds of time-histories into the vehicle-railway system, the comparative analysis of the two kinds of dynamic performances for ChinaRLS and AmericaRLS is done in terms of car body acceleration, rate of wheel load reduction, wheel/rail force, and the dynamic responses of track structure. The result shows that ChinaRLS can characterize the feature of the Chinese track irregularity better than AmericaRLS, the track irregularity with the ChinaRLS of 200km/h is superior to the AmericaRLS, and the track irregularity with the ChinaRLS of 160km/h corresponds to with the sixth of AmericaRLS.

Design and Simulation of Temperature Control System in Intermittent Reaction Kettles Based on Intelligent Fuzzy Control

2013 ◽  
Vol 380-384 ◽  
pp. 294-297 ◽  
Author(s):  
Xin Wei Li
Keyword(s):  
Control System ◽  
Fuzzy Control ◽  
Pid Control ◽  
Elevated Temperatures ◽  
Fuzzy Controller ◽  
Dynamic Performance ◽  
Temperature Curve ◽  
Time Variable ◽  
Temperature Control System ◽  
New Type

A temperature rising control system and temperature maintaining control system were designed in according to time-variable and hysteretic nature of temperature change and limitation when traditional PID control deals with nonlinear systems. A new type of intelligent fuzzy controller combination of traditional PID control and fuzzy control was designed and applied in temperature maintaining control system. The simulation results show that the holding phase at elevated temperatures and temperature, the temperature curve has a high steady-state accuracy and dynamic performance in the period of temperature rising and maintaining, and the system and controller cause a better result.

Analysis on the Dynamic Performance of Vehicles

2021 ◽  
Vol 42 ◽  
pp. 71-78
Author(s):  
Oana Victoria Oțăt ◽  
Ilie Dumitru ◽  
Laurenţiu Racilă ◽  
Dragoș Tutunea ◽  
Lucian Matei
Keyword(s):  
Initial Data ◽  
Analytical Method ◽  
Dynamic Performance ◽  
Automotive Sector ◽  
Vehicle Dynamic ◽  
Car Model ◽  
Dynamic Performances

The current accelerated developments within the automotive sector have triggered a series of performance, comfort, safety and design-related issues. Hence, oftentimes manufacturers are challenged to combine various elements so as to achieve an attractive design, without diminishing the vehicle’s dynamic performance. In order to determine the vehicle dynamic performances we carried out an analysis by two methods. In the first part of the paper, we have used the analytical method to establish the dynamic performances of a vehicle. The second part of our study addresses another method to determine the star performances of the vehicle by means of computerized simulations. The first test aimed to determine vehicle starting performances for two vehicle models, with similar technical configuration, but with the same initial data. In the second test, we aimed at determining the start performance for the same car model, with the same initial data, but for different adhesion coefficients

scholarly journals Influence of Temperature Effect on the Static and Dynamic Performance of Gas-Lubricated Microbearings

Micromachines ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 716
Author(s):  
Liangliang Li ◽  
Zhufeng Liu ◽  
Chongyu Wang ◽  
Yonghui Xie
Keyword(s):  
High Speed ◽  
Load Capacity ◽  
Dynamic Performance ◽  
Operating Environment ◽  
Low Friction ◽  
Operating Stability ◽  
Comprehensive Performance ◽  
Different Temperatures ◽  
Dynamic Performances ◽  
The Difference

Gas-lubricated microbearings are widely applied in multiple fields due to their advantages of high-speed, low friction level and other features. The operating environment of microbearings is complex, and the difference of temperature has an important influence on their comprehensive performance. In this investigation, FEM (finite element method) is employed to investigate the static, dynamic and limit characteristics of microbearings lubricated by different kinds of gas at different temperatures. The results show that the rise of temperature leads to the decline of equivalent viscosity of gas, which weakens the load capacity of microbearings, and furthermore, affects the operating stability of microbearings. The dynamic performances of microbearings at different temperatures are very different, and the two dynamic limit characteristics are more sensitive to temperature when it changes.

scholarly journals The Relationship between Isometric Force-Time Characteristics and Dynamic Performance: A Systematic Review

Sports ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 63 ◽  
Author(s):  
Danny Lum ◽  
G. Gregory Haff ◽  
Tiago M. Barbosa
Keyword(s):  
Isometric Force ◽  
Dynamic Performance ◽  
Lower Limbs ◽  
Upper Body ◽  
Original Research ◽  
Dynamic Performances ◽  
Time Variables ◽  
Force Time ◽  
The Relationship ◽  
Body Dynamic

The purpose of this article was to review the data on the relationship between multi-joint isometric strength test (IsoTest) force-time characteristics (peak force, rate of force development and impulse) and dynamic performance that is available in the current literature. Four electronic databases were searched using search terms related to IsoTest. Studies were considered eligible if they were original research studies that investigated the relationships between multi-joint IsoTest and performance of dynamic movements; published in peer-reviewed journals; had participants who were athletes or active individuals who participate in recreational sports or resistance training, with no restriction on sex; and had full text available. A total of 47 studies were selected. These studies showed significant small to large correlations between isometric bench press (IBP) force-time variables and upper body dynamic performances (r2 = 0.221 to 0.608, p < 0.05) and significant small to very large correlation between isometric squat (ISqT) (r2 = 0.085 to 0.746, p < 0.05) and isometric mid-thigh pull (IMTP) (r2 = 0.120 to 0.941, p < 0.05) force-time variables with lower body dynamic performances. IsoTest force-time characteristics were shown to have small to very large correlations with dynamic performances of the upper and lower limbs as well as performance of sporting movements (r2 = 0.118 to 0.700, p < 0.05). These data suggest that IsoTest force-time characteristics provide insights into the force production capability of athletes which give insight into dynamic performance capabilities.

Mode-switching control and stability analysis of a hybrid electromagnetic actuator for the vehicle suspension

2020 ◽  
Vol 26 (19-20) ◽  
pp. 1804-1814
Author(s):  
Renkai Ding ◽  
Ruochen Wang ◽  
Xiangpeng Meng ◽  
Long Chen
Keyword(s):  
Energy Consumption ◽  
Performance Test ◽  
Control Method ◽  
Dynamic Performance ◽  
Electrical Energy ◽  
Switching Control ◽  
Mode Switching ◽  
Electromagnetic Actuator ◽  
Electrical Energy Consumption ◽  
Dynamic Performances

To coordinate the contradictory relationship between dynamic performances and electrical energy consumption of an electromagnetic active suspension, a hybrid electromagnetic actuator that integrates with a linear motor and a hydraulic damper is developed, which can achieve active control and energy regeneration compared with the linear electromagnetic actuator. A mode-switching control method is put forward based on the modified skyhook control. The stability of the switched controller with a specific switching rule is investigated based on the Lyapunov theorem. Then, the switching control system of a hybrid electromagnetic actuator is designed. Finally, a linear electromagnetic actuator and a passive damper are taken as comparison objects, and comparative bench tests, including a dynamic performance test and an energy consumption test, are conducted. The test results show that the hybrid electromagnetic actuator with mode-switching control can balance the dynamic performances and electrical energy consumption effectively.

A Study on Calculation Method of Natural Frequency for Rubber Damped Torsional Vibration Absorbers

2014 ◽  
Author(s):  
Wen-Bin Shangguan ◽  
Yumin Wei ◽  
Subhash Rakheja ◽  
Xu Zhao ◽  
Jun-wei Rong ◽  
...  
Keyword(s):  
Fractional Derivative ◽  
Natural Frequency ◽  
Dynamic Performance ◽  
Model Parameters ◽  
Dynamic Shear ◽  
Shear Properties ◽  
Rubber Ring ◽  
Constructive Models ◽  
Dynamic Performances ◽  
The Moment

The natural frequency is the key performance parameters of a rubber materials damper, and it is determined by the static and dynamic shear properties of the rubber materials (rubber ring) and the moment of inertia of the inertia ring. The rubber ring is usually in compression state, and its static and dynamic shear properties are dependent on its sizes, compression ratio and chemical ingredients. A special fixture is designed and used for measuring static and dynamic shear performance of a rubber ring under different compression ratios in the study. To characterize the shear static and dynamic performances of rubbers, three constructive models (Kelvin-Voigt, the Maxwell and the fractional derivative constitutive model) are presented and the method for obtaining the model parameters in the fractional derivative constructive models are developed using the measured dynamic performance of a rubber shear specimen. The natural frequency of a rubber materials damper is calculated using the fractional derivative to characterize the rubber ring of the damper, and the calculated frequencies are compared with the measurements.

Modeling and Enhancement of Mckibben Pneumatic Muscle Actuators

2012 ◽  
Vol 591-593 ◽  
pp. 793-796 ◽  
Author(s):  
He Zuo ◽  
Guo Liang Tao ◽  
Xiao Cong Zhu
Keyword(s):  
Dynamic Performance ◽  
System Model ◽  
Model Parameters ◽  
Mass Ratio ◽  
Slow Time ◽  
Nonlinear Characteristics ◽  
Pneumatic Muscle ◽  
Fast Switching ◽  
Dynamic Performances ◽  
Muscle Actuators

Mckibben pneumatic muscle actuators (PMA) have many advantages such as high power-mass ratio and low price, but their strong nonlinear characteristics makes modeling and controlling very hard, which limits their applications. This paper presents the modeling of PMA and methods to enhance their dynamic performances. Considering the incorporated models of fast-switching valves and PMAs, the entire system model is modified in some aspects and the dominant model parameters are determined through experimental results to estimate the dynamic characteristics precisely. Simulation and proper experiments reveal that the dynamic performance of PMA can be improved through filling the PMA with materials of high thermal conductivity. The slow time-varying disturbance caused by the temperature variation of inner gas can be reduced much, which lowers the difficulty of controlling.

Lattice Light Steel Frame System and Application

2011 ◽  
Vol 105-107 ◽  
pp. 1110-1113
Author(s):  
Bo Ding ◽  
Huan Qing Jiang ◽  
Hong Xia Wan ◽  
Feng Zhang
Keyword(s):  
High Speed ◽  
Design Method ◽  
Calculation Model ◽  
Steel Frame ◽  
Calculation Results ◽  
Frame System ◽  
Practical Engineering ◽  
Steel Consumption ◽  
New Type ◽  
New System

Lattice light steel frame is a new type of structural system, combining general steel framework which is composed of lattice column and lattice beam with lattice light steel keel of the partitions and floors, the system takes full advantages of both structural systems, with high speed construction, less steel consumption, good earthquake-resistance etc., and possesses good prospects. The paper describes the system construction approach and the characteristics of lattice light steel frame system, and provides a project example of a villa. The design method and calculation model of the project are presented. Calculation results meet the specifications’ requirements, proving the new system can be applied to practical engineering. The paper gives guidance for application and research of this new system.

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