scholarly journals A Study on Multi-body Dynamic Modelling and Optimization for Mechanical Quick Closing Valve

2018 ◽  
Vol 167 ◽  
pp. 03004
Author(s):  
Wang Bo ◽  
Li Junyan ◽  
Wu Lifang ◽  
Chen Xuekai
Keyword(s):  
Lagrange Equation ◽  
Structural Parameters ◽  
Dynamic Modelling ◽  
Friction Model ◽  
Normal Contact ◽  
Control Rod ◽  
Multi Body ◽  
Off Time ◽  
Body Dynamic ◽  
Modelling And Optimization

The multi-body dynamic modelling and optimization methods of mechanical quick closing valve are studied in this paper. The Lagrange equation is specified characterizing the closing process. Normal contact force and tangent friction force between the components are obtained by using equivalent spring-damper model and no-linear coulomb friction model. The theoretical result of the valve’s kinematic response is verified by the experiment. In order to analyse the relationship between structural parameters and the closing behaviour intuitively, a single degree of freedom model is provided. It is shown that the mass of the control rod is the key parameter exerting important influence on the cut-off time of the valve. The cut-off time will be shortened by about 1.2ms while the mass of control rod reduces 0.01kg.

Performance Improvement in Steering Torque Simulator With Multibody Vehicle Model

2013 ◽  
Author(s):  
Toshimasa Takouda ◽  
Yoshinori Owaki ◽  
Masashi Tsushima ◽  
Taichi Shiiba
Keyword(s):  
Dynamic Analysis ◽  
Friction Model ◽  
Experimental Result ◽  
Vehicle Model ◽  
Step Size ◽  
Real Time Analysis ◽  
Multibody Dynamic ◽  
Multi Body ◽  
Steering Torque ◽  
Body Dynamic

The aim of this study is to improve the performance of a steering torque simulator with a multibody vehicle model. From the perspective of the calculation speed, the augmented formulation and the penalty method were investigated as the formulation of the multibody dynamic analysis. In this study, the step size of the real-time analysis was shortened by embedding matrix libraries to the multibody dynamic analysis. In addition, the friction characteristics of the steering rack of an actual vehicle was experimentally evaluated in order to enhance the reality of the developed simulator. The friction model was identified on the basis of the experimental result and was applied to the multi-body dynamic analysis. A slalom test was conducted with the developed simulator and was compared with the experiment of an actual vehicle.

Multi-body dynamic modelling and flight control for an asymmetric variable sweep morphing UAV

2014 ◽  
Vol 118 (1204) ◽  
pp. 683-706 ◽  
Author(s):  
L. Tong ◽  
H. Ji
Keyword(s):  
Dynamic Model ◽  
Flight Control ◽  
Integrated Design ◽  
Dynamic Modelling ◽  
Design Procedure ◽  
Sweep Angle ◽  
Trajectory Tracking Control ◽  
Multi Body ◽  
Body Dynamic ◽  
Morphing Uav

AbstractIn this paper, the multi-body dynamic model of an asymmetric variable sweep wing morphing UAV is built based on Kane’s method. This model describes the UAV’s transient behaviour during morphing process and the dynamic characteristic of the variable sweep wings. An integrated design of trajectory tracking control via constrained backstepping method is presented then. The idea of aircraft roll control through asymmetric wing sweep angle changes rather than traditional aileron is explored and used in the fight control design. The control of variable sweep wings is designed as well based on the presented dynamic model. Command filters are used in the backstepping design procedure to accommodate magnitude, rate and bandwidth constraints on virtual states and actuator signals. Stability of the closed-loop system can be proved in the sense of Lyapunov. Simulation of tracking a desired trajectory which contains two manoeuvres demonstrates the feasibility of the proposed protocol and the morphing wing roll controller.

Motorcycle Dynamics Modeling and Simulation Based on Road Simulation

2009 ◽  
Vol 16-19 ◽  
pp. 307-312
Author(s):  
Xi Hong Zou ◽  
Xiao Hui Shi ◽  
Quan Shi ◽  
Shun Li Xiao
Keyword(s):  
Lagrange Equation ◽  
Dynamics Modeling ◽  
Load Spectra ◽  
Simulation Based ◽  
Simulation And Experiment ◽  
Space Formulation ◽  
Multi Body ◽  
Motorcycle Dynamics ◽  
Body Dynamic ◽  
Driving Signal

Based on the stimulation and restriction of road simulation, the 5-DOF motorcycle multi-body dynamic model is derived, and the differential equation of motion and state-space formulation are developed according to Lagrange Equation. By iterating the load spectra, which was sampled on Hainan Proving Ground, the driving signal of motorcycle road simulation is obtained. With the driving signal as input, the motorcycle dynamics is simulated using MATLAB program, then the simulation and experiment are compared. The result shows that motorcycle dynamics can be analyzed and estimated precisely by combining road simulation with computer simulation.

Modeling and simulation of dynamics of a planar-motion rigid body with friction and surface contact

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744021 ◽  
Author(s):  
Xiaojun Wang ◽  
Jing Lv
Keyword(s):  
Rigid Body ◽  
Frictional Contact ◽  
Lagrange Equation ◽  
Linear Complementarity ◽  
Friction Model ◽  
Contact Forces ◽  
Planar Motion ◽  
Stick Slip ◽  
Normal Contact ◽  
Friction Law

The modeling and numerical method for the dynamics of a planar-motion rigid body with frictional contact between plane surfaces were presented based on the theory of contact mechanics and the algorithm of linear complementarity problem (LCP). The Coulomb’s dry friction model is adopted as the friction law, and the normal contact forces are expressed as functions of the local deformations and their speeds in contact bodies. The dynamic equations of the rigid body are obtained by the Lagrange equation. The transition problem of stick-slip motions between contact surfaces is formulated and solved as LCP through establishing the complementary conditions of the friction law. Finally, a numerical example is presented as an example to show the application.

A multi-body dynamic study of vibration of a planetary gear train with the planetary bearing fault

2019 ◽  
Vol 233 (3) ◽  
pp. 677-695 ◽  
Author(s):  
Jing Liu ◽  
Linfeng Wang ◽  
Jinlei Ma ◽  
Wennian Yu ◽  
Yimin Shao
Keyword(s):  
Dynamic Model ◽  
Dynamic Modelling ◽  
Planetary Gear ◽  
Elastic Support ◽  
Gear Train ◽  
Radial Clearance ◽  
Ring Gear ◽  
Planetary Gear Train ◽  
Multi Body ◽  
Body Dynamic

Local faults including pits and spalls in any planet bearing can greatly affect the vibration of the planetary gear train, as well as the elastic support of the ring gear. However, the dynamic modelling methods in previous work can only formulate the local fault and the elastic support of the ring gear independently. To address this issue, a multi-body dynamic model for a planetary gear train with a local fault in the planet bearing and an elastic ring gear foundation are introduced to analyze the effect of local fault on the vibration. The local fault in the planet bearing is modelled as a rectangular one. Both the planet bearings including the radial clearance and ring gear with an elastic foundation are considered in the multi-body dynamic model. The contact stiffnesses and damping coefficients of gears and bearings are calculated by the methods reported in the literature. A Coulomb friction model is adopted to model the frictions between mating components of the system. In order to validate the proposed multi-body dynamic model, its simulation results are directly compared with those from theoretical methods as well as the experimental methods reported in the literature. Moreover, parameter studies are conducted to discuss the effects of local faults in the planet-bearing races, the sun gear speed, and the carrier moment on the vibration of the planetary gear train. The analyzing results of this study can provide some guidance for detection approaches of local faults in the planet bearings of planetary gear trains through vibration analysis.

Study on Lateral Stability of Vehicle-Trailer System Based on Multi-Body Dynamic Simulation

2013 ◽  
Vol 765-767 ◽  
pp. 345-350
Author(s):  
Ai Jun Ren ◽  
Zhi Cheng Wu ◽  
Jie Bao
Keyword(s):  
Dynamic Model ◽  
Critical Velocity ◽  
Degrees Of Freedom ◽  
Structural Parameters ◽  
Damping Ratio ◽  
Dynamic Responses ◽  
Lateral Stability ◽  
Linear Dynamic ◽  
Multi Body ◽  
Body Dynamic

With a classical 4 degrees of freedom linear dynamic model of vehicle-trailer system in the yaw plane, preliminary study on lateral stability is carried out by means of analyzing systems damping ratio. The results show that structural parameters have important influence on lateral stability of vehicle-trailer system. Based on that study, a concept of critical velocity with zero damping ratio as an index is present. With the help of MSC.ADAMS, a multi-body dynamic model of a real vehicle-trailer system is built subsequently and the dynamic responses of vehicle-trailer system running on flat road and rough road is simulated respectively. The simulation results indicated that the characteristics of lateral stability of both of the linear dynamic model and the multi-body dynamic model running on flat road are similar. The critical velocity of multi-body dynamic model running on rough road decreases due to the disturbance from road. Since effects of road, nonlinear wheels, suspension structure and load transfer are taken into consideration, multi-body dynamic model of vehicle-trailer system running on the rough road could be more perfectly characterizing the lateral stability of vehicle-trailer system.

scholarly journals Sensitivity Analysis of Holdback Bar Release Load during Catapult-Assisted Takeoff of Carrier-Based Aircraft

2022 ◽  
Vol 12 (2) ◽  
pp. 785
Author(s):  
Enze Zhu ◽  
Zhipeng Zhang ◽  
Hong Nie
Keyword(s):  
Friction Coefficient ◽  
Kinetic Model ◽  
Contact Surface ◽  
Structural Parameters ◽  
Friction Model ◽  
Release Process ◽  
Factors Affecting ◽  
Mechanical Models ◽  
Multi Body ◽  
Surface Angle

The release load of holdback bar will affect the safety of catapult-assisted takeoff of carrier-based aircraft, and the accurate control of releasing the load will ensure success. The magnitude and the control accuracy of release load are important parameters which impact the takeoff performance, therefore unstable release load and insufficient release precision are the main factors affecting the takeoff safety. In this paper, mechanical models of the carrier-based aircraft in the catapult-assisted takeoff tensioning state and gliding state after release are established based on multi-body dynamics, contact mechanics and tribological theory, and the influence of the release load of the holdback bar on the catapult-assisted takeoff performance is analyzed. Furthermore, a kinetic model of the holdback bar device is established, and the kinetic characteristics of the release process of the holdback bar are studied. Based on the kinetic model and friction model of the holdback bar, the influencing factors of the sensitivity of the holdback bar release load are analyzed and the structural parameters are optimized. The results show that the released load decreases slowly with the increase of the contact surface angle of the holdback bar structure and increases rapidly when that angle reaches the critical value; besides, the release load increases slowly with the increase of the friction coefficient of the contact surface and increases faster when the critical friction coefficient is reached.

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