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.

scholarly journals Combined simulation of heavy truck stability under sudden and discontinuous direction change of crosswind with computational fluid dynamics and multi-body system vehicle dynamics software

2018 ◽  
Vol 10 (7) ◽  
pp. 168781401878636
Author(s):  
Zhe Zhang ◽  
Jie Li ◽  
Wencui Guo
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Closed Loop ◽  
System Simulation ◽  
Open Loop ◽  
Lateral Acceleration ◽  
Body System ◽  
Direction Change ◽  
Heavy Truck ◽  
Multi Body

The method of yaw model is used to establish aerodynamic property of heavy truck in computational fluid dynamics and wind tunnel test. A model of multi-body system simulation for heavy truck is built based on design and measure data from body, driving system, steering system, braking system, and powertrain system with TruckSim. Aerodynamic reference point of Society of Automotive Engineers (SAE) and aerodynamic coefficients are as the interface to integrate computational fluid dynamics and multi-body system simulation. A sudden and discontinuous direction change of crosswind is set up in multi-body system simulation, and dynamic performance of the heavy truck is performed by open-loop and closed-loop simulation. Under the given simulation case, lateral offset of the truck for open-loop simulation is 1.55 m and more than that for closed-loop simulation; the roll rate range of both simulations is −1.49°/s to 1.695°/s, the range of lateral acceleration is −0.497 m/s2 to 0.447 m/s2 in open-loop simulation, the range of lateral acceleration is −0.467 m/s2 to 0.434 m/s2 in closed-loop simulation; the range of yaw rate is −1.36°/s to 1.284°/s in open-loop simulation, the range of yaw rate is −0.703°/s to 0.815°/s in closed-loop simulation. The results show that combined simulation of the heavy truck stability can be completed by computational fluid dynamics and multi-body system software under sudden and discontinuous direction change of crosswind.

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.

Dynamic Analysis and Simulation of Deployable Planar Truss Mechanism

2009 ◽  
Vol 69-70 ◽  
pp. 649-654
Author(s):  
Yi Sun ◽  
G.K. Shi ◽  
J.H. Shan ◽  
Ming Feng Dong
Keyword(s):  
Dynamic Analysis ◽  
Mechanism Design ◽  
Dynamic Model ◽  
Dynamic Equation ◽  
Optimization Design ◽  
Dynamic Theory ◽  
Lagrange Equation ◽  
Body System ◽  
Force Condition ◽  
Multi Body

This document researches on the improved deployable planar truss mechanism design and builds an dynamic equation of the model based on Lagrange equation in the multi-body system dynamic theory. The dynamic model is established to simulate the motion of the system and calculate the force condition of members respectively by ADAMS. Finally, the significant references for the elasto-dynamic analysis and optimization design of the truss mechanism will be provided.

A regularization method for solving dynamic problems with singular configuration

2021 ◽  
pp. 146441932110619
Author(s):  
Liusong Yang ◽  
Shifeng Xue ◽  
Xingang Zhang ◽  
Wenli Yao
Keyword(s):  
Regularization Method ◽  
Null Space ◽  
Mechanical Energy ◽  
Iteration Step ◽  
Dynamic Simulations ◽  
Gauss Principle ◽  
Space Formulation ◽  
Singular Configuration ◽  
Multi Body ◽  
Four Bar Linkage

In the simulation process for multi-body systems, the generated redundant constraints will result in ill-conditioned dynamic equations, which are not good for stable simulations when the system motion proceeds near a singular configuration. In order to overcome the singularity problems, the paper presents a regularization method with an explicit expression based on Gauss principle, which does not need to eliminate the constraint violation after each iteration step compared with the traditional methods. Then the effectiveness and stability are demonstrated through two numerical examples, a slider-crank mechanism and a planar four-bar linkage. Simulation results obtained with the proposed method are analyzed and compared with augmented Lagrangian formulation and the null space formulation in terms of constraints violation, drift mechanical energy and computational efficiency, which shows that the proposed method is suitable to perform efficient and stable dynamic simulations for multi-body systems with singular configurations.

Dynamic Performance of High-Speed Electric Multiple Unit within Multi-Body System Simulation

2019 ◽  
Vol 12 (4) ◽  
pp. 339-349
Author(s):  
Junguo Wang ◽  
Daoping Gong ◽  
Rui Sun ◽  
Yongxiang Zhao
Keyword(s):  
High Speed ◽  
Rapid Development ◽  
Dynamic Performance ◽  
Body System ◽  
High Speed Railway ◽  
Evaluation Indexes ◽  
Actual Operation ◽  
Multiple Unit ◽  
The Stability ◽  
Multi Body

Background: With the rapid development of the high-speed railway, the dynamic performance such as running stability and safety of the high-speed train is increasingly important. This paper focuses on the dynamic performance of high-speed Electric Multiple Unit (EMU), especially the dynamic characteristics of the bogie frame and car body. Various patents have been discussed in this article. Objective: To develop the Multi-Body System (MBS) model of EMU, verify whether the dynamic performance meets the actual operation requirements, and provide some useful information for dynamics and structural design of the proposed EMU. Methods: According to the technical characteristics of a typical EMU, a MBS model is established via SIMPACK, and the measured data of China high-speed railway is taken as the excitation of track random irregularity. To test the dynamic performance of the EMU, including the stability and safety, some evaluation indexes such as wheel-axle lateral forces, wheel-axle lateral vertical forces, derailment coefficients and wheel unloading rates are also calculated and analyzed in detail. Results: The MBS model of EMU has better dynamic performance especially curving performance, and some evaluation indexes of the stability and safety have also reached China’s high-speed railway standards. Conclusion: The effectiveness of the proposed MBS model is verified, and the dynamic performance of the MBS model can meet the design requirements of high-speed EMU.

scholarly journals Impact of Increased Travel Speed of a Transportation Set on the Dynamic Parameters of a Mine Suspended Monorail

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1528
Author(s):  
Kamil Szewerda ◽  
Jarosław Tokarczyk ◽  
Andrzej Wieczorek
Keyword(s):  
Computational Model ◽  
Travel Speed ◽  
Body System ◽  
Emergency Braking ◽  
System Method ◽  
Underground Coal Mines ◽  
Program Environment ◽  
Underground Transportation ◽  
Multi Body ◽  
Transportation Routes

The method of increasing the efficiency of using one of the most common means of auxiliary transport in underground coal mines—suspended monorails—is presented. Increase of velocity is one of the key parameters to improve the efficiency and economical effect related with the underground auxiliary transport. On the other hand, increasing the velocity results in bigger value of force acting on the suspended monorail route and its suspensions. The most important issue during increasing the velocity is ensuring the required safety for the passengers and not overloading the infrastructure. In order to analyze how increasing velocity influences the level of loads of the route suspension and the steel arch loads, the computational model of suspended monorail was developed. The computational model included both the physical part (embedded in the program environment based on the Multi-Body System method) and the components of the monorail control system. Two independent software environments were cooperating with each other through the so-called co-simulation. This model was validated on the base of results obtained on the test stand. Then, the numerical simulations of emergency braking with different values of velocity were conducted, which was not possible with the use of physical objects. The presented study can be used by the suspended monorail’s producers during the designing process, and leads to increase the safety on underground transportation routes.

A dynamic model for deteriorating products in a closed-loop supply chain

2021 ◽  
Vol 108 ◽  
pp. 102269
Author(s):  
Mitra Moubed ◽  
Yasamin Boroumandzad ◽  
Ali Nadizadeh
Keyword(s):  
Supply Chain ◽  
Dynamic Model ◽  
Closed Loop ◽  
Closed Loop Supply Chain
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