Application of Multi Body System Coupling Dynamic Model in Posture Stability Evaluation of Sports

2021 ◽  
Author(s):  
Haijin Pan
Keyword(s):  
Dynamic Model ◽  
Evaluation Method ◽  
Human Motion ◽  
Stability Evaluation ◽  
Body System ◽  
Coupling Dynamic ◽  
Multi Body ◽  
System Coupling ◽  
Posture Stability ◽  
Coupling Dynamic Model

Due to the lack of more precise and complete data support, the reliability of posture stability evaluation method based on common technology is poor. In the face of such problems, the application of multi-body system coupling dynamic model in the evaluation of sports posture stability is proposed. The coupling dynamic model of human motion posture is established, and the relevant data of human motion posture is collected. The complete data of human motion posture is obtained by solving the dynamic model. Choose the appropriate stability evaluation index, calculate the stability evaluation index, divide the stability level, and realize the evaluation of posture stability. The experimental results show that: the application of multi-body system coupling dynamic model in the stability evaluation method makes the time delay and data error of the evaluation method small, and its overall reliability is improved.

scholarly journals Thermos-Solid-Gas Coupling Dynamic Model and Numerical Simulation of Coal Containing Gas

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Xiao Fukun ◽  
Meng Xin ◽  
Li Lianchong ◽  
Liu Jianfeng ◽  
Liu Gang ◽  
...  
Keyword(s):  
Principal Stress ◽  
Dynamic Model ◽  
Gas Flow ◽  
Flow Behavior ◽  
Coupling Model ◽  
Gas Pressure ◽  
Permeability Model ◽  
Gas Seepage ◽  
Coupling Dynamic ◽  
Coupling Dynamic Model

Based on gas seepage characteristics and the basic thermo-solid-gas coupling theory, the porosity model and the dynamic permeability model of coal body containing gas were derived. Based on the relationship between gas pressure, principal stress and temperature, and gas seepage, the thermo-solid-gas coupling dynamic model was established. Initial values and boundary conditions for the model were determined. Numerical simulations using this model were done to predict the gas flow behavior of a gassy coal sample. By using the thermo-solid-gas coupling model, the gas pressure, temperature, and principal stress influence, the change law of the pressure field, displacement field, stress field, temperature field, and permeability were numerically simulated. Research results show the following: (1) Gas pressure and displacement from the top to the end of the model gradually reduce, and stress from the top to the end gradually increases. The average permeability of the Y Z section of the model tends to decrease with the rise of the gas pressure, and the decrease amplitude slows down from the top of the model to the bottom. (2) When the principal stress and temperature are constant, the permeability decreases first and then flattens with the gas pressure. The permeability increases with the decrease of temperature while the gas pressure and principal stress remain unchanged.

scholarly journals A new vertical dynamic model for railway vehicle with passenger-train-track coupling vibration

2019 ◽  
Vol 234 (1) ◽  
pp. 134-146
Author(s):  
Yuewei Yu ◽  
Leilei Zhao ◽  
Changcheng Zhou
Keyword(s):  
Dynamic Model ◽  
Railway Vehicle ◽  
Train Track ◽  
Passenger Train ◽  
Railway Vehicles ◽  
Vertical Coupling ◽  
Track System ◽  
Coupling Dynamic ◽  
Train System ◽  
Coupling Dynamic Model

In order to further reveal the vertical random vibration characteristics of railway vehicles, using the system engineering method, taking the passenger, the train system, and the track system (ballast track) as a unified whole, a passenger-train-track vertical coupling dynamic model is established, and the vibration differential equations of the model are derived. In the model, passengers are regarded as a single-degree-of-freedom system attached to the bottom of the carriage, the train system is represented as a 10-degree-of-freedom multi-rigid body model, the track system is regarded as the infinite long Euler beam model with three layers of continuous elastic point support, and the Hertz nonlinear elastic contact theory is applied to the wheel and rail coupling relationship. Based on this, the time-domain numerical solution of the passenger-train-track vertical coupling dynamic model is given by using Newmark- β implicit integration algorithm, and the correctness of the model is verified by the real vehicle test. This study can provide some theoretical basis for the design of railway vehicles and provide fundamentals for the coordinated control and system optimization of railway vehicle ride comfort.

Effects of High-Speed Railway in Tunnel on Vibration Response of Upper Building

2013 ◽  
Vol 482 ◽  
pp. 155-162
Author(s):  
Si Hui Xu ◽  
Xiao Hui Zhang ◽  
Han Chen
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Reaction Force ◽  
Element Model ◽  
Vibration Response ◽  
Vibration Level ◽  
High Speed Railway ◽  
Proper Distance ◽  
Coupling Dynamic ◽  
Coupling Dynamic Model

In order to study the effects of high-speed railway in tunnel on vibration response of upper building, the Vehicle-Track-Tunnel-Soil-Building coupling dynamic model was established, and the reaction force of fasteners was used to transmit between Vehicle-Track coupling dynamic model and Tunnel-Soil-Building finite element model. According to modal analysis for typical section of building, sensitive frequency range and sensitive structure locations were obtained. In terms of two conditions, Tunnel-Building Integrated Structure and building are evaded from tunnel for some distance, 1/3 octave vibration level and VLZ vibration acceleration level for all measuring points were calculated to analyze the vibration response of building. The results are shown as follows: for Tunnel-Building Integrated Structure, the overall vibration level is high,which is above 65dB. 2-3dB will be reduced by decreasing speed and improving standard of track. when building is evaded from tunnel for some distance, with larger evaded distance, the vibration response is slighter. However, when evaded distance is above 30m, vibration may be amplified ,so its necessary to select proper distance. Vibration response of structure is most strong when 4 lines meet under building, so strict limitation on meeting condition of trains can effectively reduce vibration level.

Research on Solid-Gas Coupling Dynamic Model for Loaded Coal Containing Gas

2012 ◽  
Vol 594-597 ◽  
pp. 446-451
Author(s):  
Deng Ke Wang ◽  
Jian Ping Wei ◽  
Heng Jie Qin ◽  
Le Wei
Keyword(s):  
Dynamic Model ◽  
Gas Adsorption ◽  
Coupling Model ◽  
Elastoplastic Material ◽  
The Finite Element Method ◽  
Deformation Stages ◽  
Loading Case ◽  
Porosity And Permeability ◽  
Coupling Dynamic ◽  
Coupling Dynamic Model

Considering the variation of the porosity and permeability of coal containing gas at differential deformation stages, a dynamic model for porosity and permeability is developed based on the previous researches. Furthermore, taking coal containing gas as a kind of isotropic elastoplastic material and taking into account the effect of gas adsorption, the stress and seepage equations are derived and, the solid gas coupling model for coal containing gas is constructed, which is appropriate to describe the skeleton deformability of coal containing gas and the compressibility of gas under the solid-gas interaction condition. In addition, the numerical simulation model is built by using the finite element method, and the numerical calculation solution of the model for a special loading case is given in term of the constraint conditions and corresponding parameters. The research results may have significance for further enriching and improving solid-gas coupling theories for coal containing gas.

scholarly journals A 3D Direct Vehicle-Pavement Coupling Dynamic Model and Its Application on Analysis of Asphalt Pavement Dynamic Response

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Peng Cao ◽  
Changjun Zhou ◽  
Decheng Feng ◽  
Youxuan Zhao ◽  
Baoshan Huang
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Dynamic Model ◽  
Static Analysis ◽  
Moving Load ◽  
Dynamic Responses ◽  
Pavement Surface ◽  
Coupling Dynamic ◽  
Pavement Structure ◽  
Coupling Dynamic Model

Currently dynamic response of the pavement structure is widely studied in pavement engineering. A 3D direct vehicle-pavement coupling dynamic model was developed to describe the pavement dynamic responses in this paper. The moving vehicle was simplified as spring-dashpot components, and the pavement structure was simulated using three-dimension finite element model. Based on Newton iteration and central difference integration algorithm, the static and dynamic coupling reactions between the pavement structure and vehicle were considered using finite element platform ABAQUS. The numerical results fit analytic results very well in static analysis and fit experiment results in dynamic analysis well too. The simulated results indicate that the dynamic pavement surface deflection is much higher than the situation in static analysis, due to the overlapping effect. This phenomenon enhances when vehicle speed increases. A discontinuous zone of shear stress was observed on the base surface between the location under moving load and the location the moving load just passed. It was also found that the vertical fluctuation exists on the vehicle even if there is no roughness on the pavement surface. In general, the developed 3-D direct vehicle-pavement coupling dynamic model was validated to be effective on evaluating pavement dynamic responses.

Dynamic Modeling and Numeration of Flexible Multi-Body System with Closed Loop

2010 ◽  
Vol 44-47 ◽  
pp. 1519-1524
Author(s):  
Shu Qing Liu ◽  
Xing Song Wang
Keyword(s):  
Dynamic Model ◽  
Closed Loop ◽  
Narrow Range ◽  
Null Space ◽  
Orthogonal Basis ◽  
Natural Coordinates ◽  
Body System ◽  
Multi Body ◽  
Four Bar Linkage ◽  
Flexible Linkage

The dynamic model of flexible multi-body system with closed loop is described with natural coordinates. The method is formulaic and especially appropriate to the modeling of system with repetitive substructures, but Lagrange multipliers as unknown variables are contained in the model. The dynamic model is reduced to a system with minimum dimensions by means of null-space orthogonal basis of constraint Jacobin. The result is correspondence with the dynamic model of rigid multi- body system while the rigid and flexible coupling is considered. The numerical method and the simulation steps are given in detail. Numerical example dealing with a flexible parallel four-bar linkage widely used in engineering illustrates the performance of the proposed method. The dynamic response of the angle between flexible linkage and horizontal axis are presented. The results indicate that there are clearly fluctuation in the angular velocity and acceleration of crank. The motion of connecting linkage contains not only translation but also narrow range rotation especially in the start instant.

A Coupling Dynamic Model for Interfacial Reaction between Slag and Metal of Stainless Steelmaking by Chromium Ore Smelting Reduction in a Converter

2010 ◽  
Vol 26-28 ◽  
pp. 706-709
Author(s):  
Yan Liu ◽  
Mao Fa Jiang ◽  
Li Xian Xu
Keyword(s):  
Dynamic Model ◽  
Production Efficiency ◽  
Processing Route ◽  
Smelting Reduction ◽  
Chromium Ore ◽  
Rate Determining Step ◽  
Coupling Dynamic ◽  
Refining Time ◽  
Coupling Dynamic Model ◽  
Improve Production Efficiency

For describing and resolving the process of chromium ore smelting reduction preferably, the coupling dynamic model was established using metallurgical thermodynamics, dynamics and reaction engineering. The different influencing factors were investigated and discussed. The results of the model show that the mass transfer of Cr2O3 in the slag phase is rate-determining step. The initial hot metal should contain definite chrome metal and the yield of chromium in slag should be controlled properly at 1560°C so as to decrease refining time considerably and improve production efficiency for producing stainless steel crude melts in a converter. A reference and basis for the constitution of rational processing route in a practical converter steelmaking have been afforded.

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