scholarly journals Analysis of Carrier-Based Aircraft Catapult Launching Based on Variable Topology Dynamics

2021 ◽  
Vol 11 (19) ◽  
pp. 9037
Author(s):  
Hu Chen ◽  
Xingbo Fang ◽  
Hong Nie
Keyword(s):  
Dynamic Model ◽  
Pitch Angle ◽  
Solution Method ◽  
Multibody System ◽  
Landing Gear ◽  
Dynamics Model ◽  
Topological Relationships ◽  
Variable Topology ◽  
Free Running ◽  
The Moment

The catapult process of a carrier-based aircraft includes multiple links such as catapult tensioning, separation of the holding rod, dragging and running, separation of the catapult and drag shuttle, and free running. The connection relationships between the front landing gear of the carrier-based aircraft and other related components in each link are different, therefore, it is necessary to adjust the topological relationships of the dynamic model in real time, when solving the catapult dynamics of a carrier-based aircraft. In this paper, a dynamic model of the multibody system of the catapult take-off is established, and a variable topology solution is carried out for the dynamic model by adjusting dynamic augmentation equations; in addition, a dynamic analysis of a carrier-based aircraft catapult and take-off process is carried out. A catapult dynamics model and variable topology solution method were established, which solved the changes at the moment of the restraining rod separation, catapult rod separation, and catapult tackle during the aircraft catapult take-off. After the restraining rod was separated from the front landing gear, the catapult force was transmitted to the rear strut, which instantly increased the load of the rear strut by 238.5 kN. In addition, after the carrier-based aircraft reached the end of the catapult’s stroke, the catapult rod was separated from the catapult tow shuttle then unloaded, and the load of the rear strut was reduced from 486.2 kN to −20.3 kN. Under the protruding effect of the nose gear, the pitch angle of the carrier-based aircraft increased rapidly from −0.93° and reached 0.54° when the carrier-based aircraft rushed out of the deck.

Dynamic model of an air spring and integration into a vehicle dynamics model

2008 ◽  
Vol 222 (10) ◽  
pp. 1813-1825 ◽  
Author(s):  
F Chang ◽  
Z-H Lu
Keyword(s):  
Dynamic Model ◽  
Vehicle Dynamics ◽  
Simulation Method ◽  
Heat Transfer Process ◽  
Spring Model ◽  
Dynamics Model ◽  
Air Spring ◽  
Full Vehicle ◽  
Body Dynamics ◽  
Multi Body

It is worthwhile to design a more accurate dynamic model for air springs, to investigate the dynamic behaviour of an air spring suspension, and to analyse and guide the design of vehicles with air spring suspensions. In this study, a dynamic model of air spring was established, considering the heat transfer process of the air springs. Two different types of air spring were tested, and the experimental results verified the effectiveness of the air spring model compared with the traditional model. The key factors affecting the computation accuracy were studied and checked by comparing the results of the experiments and simulations. The new dynamic model of the air spring was integrated into the full-vehicle multi-body dynamics model, in order to investigate the air suspension behaviour and vehicle dynamics characteristics. The co-simulation method using ADAMS and MATLAB/Simulink was applied to integration of the air spring model with the full-vehicle multi-body dynamics model.

scholarly journals EXPERIMENTAL EXPERIENCE IN STUDYING THE WEIGHT DYNAMICS OF ROTATING GYROSCOPES AND THEIR ROTATION FEATURES AT CRITICALLY LOW SPEEDS, INCLUDING AT SUNRISE AND DURING A LUNAR-SOLAR ECLIPSE

Metaphysics ◽  
2020 ◽  
pp. 102-114
Author(s):  
A. M Panichev
Keyword(s):  
Solar Eclipse ◽  
Weight Changes ◽  
Running Time ◽  
Left Hand ◽  
Speed Range ◽  
Angular Velocities ◽  
Free Running ◽  
The Moment ◽  
Right And Left Hand ◽  
Amplitude Characteristics

The cycle of experiments with free-rolling gyroscopes at different angular velocity intervals including those on scales with continuous-discrete weight registration was carried out. We concluded that the free-running time of gyroscopes in one interval of angular velocities can vary greatly (within hundreds of percent). Measuring the free running time of a gyroscope during a solar eclipse has shown a connection between registered fluctuations in the gyroscope behavior and the eclipse stroke. The data obtained during the periods of sunrise indicate that the gyroscope can react at the moment of the sunrise while recording the true ascent, as well as the ascent preceding the true one with a difference of 8 minutes. Statistical analysis of the graphs of weight changes of the disk at right and left-hand free rotation in the speed range from 5000 to 250 rpm showed that the abnormal weight changes recorded at certain “critical” frequencies with different directions of rotation reliably differ in amplitude characteristics.

scholarly journals Steering Control Method for an Underactuated Unicycle Robot Based on Dynamic Model

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Hongzhe Jin ◽  
Yang Zhang ◽  
Hui Zhang ◽  
Zhangxing Liu ◽  
Yubin Liu ◽  
...  
Keyword(s):  
Angular Velocity ◽  
Control Strategy ◽  
Pitch Angle ◽  
Control Method ◽  
Steering Control ◽  
Dynamics Model ◽  
Gyroscope System ◽  
Simulation Results ◽  
Balance Structure ◽  
Gyroscope Precession

This paper proposes a lateral balancing structure based on precession effect of double-gyroscopes and its associated control strategy of the steering for an underactuated unicycle robot. Double-gyroscopes are symmetrically designed on the top of the unicycle robot and utilized to adjust the lateral balance of system. Such design can inhibit the disturbance of the gyroscope system to the pitch angle and is beneficial to maintain the lateral balance in the case of large roll angle fluctuations. Based on the analysis of the dynamics model, the gyroscope precession effects will be caused by the angular velocity of the bottom wheel and the roll angular velocity, i.e., resulting in a torque in the direction of the yaw. Then, a rapid response control strategy is proposed to use the torque to control the steering. Simulation results demonstrate the rationality of the lateral balance structure and the feasibility of the steering control method.

Dynamic Modeling and Vibration Analysis of the Drum Washing Machine Based on Four-Terminal Parameter Method

2012 ◽  
Vol 501 ◽  
pp. 179-184
Author(s):  
Jun Fei Wu ◽  
Hui Li ◽  
Xue Zheng Yang ◽  
Xu Ping Zhang
Keyword(s):  
Steady State ◽  
Dynamic Model ◽  
Parameter Method ◽  
Steady State Response ◽  
Dynamics Model ◽  
Washing Machine ◽  
Basic Principles ◽  
State Response ◽  
Theoretical Support ◽  
Vibration Mechanism

In this study, the drum washer’s dynamic model has been conducted using Four-terminal parameter method. Firstly, the basic principles and advantages of the four-terminal parameters has been explained, and we have analyzed the vibration mechanism of the drum washer. Secondly, the drum washer was simplified ,and we extracted its dynamic model. Thirdly, we solve each of its components by using the four-terminal parameter method,and according to the connection between the components, determine each component and the system’s four-terminal parameters .Then, deduce the system’s matrix equations,get the complex steady-state response and steady-state response under sinusoidal excitation of the system. Last, input the drum washer’s actual parameters ,we can see that four-terminal parameter method dynamics model is correct. In a word, it is easy to analyze the vibration of complex systems. This paper is designed to provide theoretical support for the design of the drum washer’s damping device.

The Dynamics Model Analysis of Drying Process in Gelcasting Method

2014 ◽  
Vol 1025-1026 ◽  
pp. 366-371
Author(s):  
Xiao Long Zhang ◽  
Bo Li ◽  
Jun Xian Ye ◽  
Ji Zhou
Keyword(s):  
Qualitative Analysis ◽  
Dynamic Model ◽  
Quantitative Description ◽  
Drying Shrinkage ◽  
Evaporation Process ◽  
Drying Process ◽  
Dynamics Model ◽  
One Dimensional ◽  
Ceramic Components ◽  
The One

<span><span lang="DE">Gelcasting is a widely<br />used method for manufacturing ceramic components. Currently the research on drying process is limited to qualitative analysis for drying process. In order to reveal the mechanism of the gelcast bisque’s drying process, the one-dimensional dynamics model for drying process has been formulated, based on the microscopic quantitative description of the evaporation process and mass transferring process through the gelcast bisque. Then the model has been modified with the consideration of the capillarity effect and the bisque’s drying shrinkage influence. By comparing with the experimental results the one-dimensional dynamic model of drying process can be proved to accurately describe the bisque’s drying process.</span>

Experimental Model Validation for a Flexible Robot With a Prismatic Joint

1990 ◽  
Vol 112 (3) ◽  
pp. 315-323 ◽  
Author(s):  
Ye-Chen Pan ◽  
A. Galip Ulsoy ◽  
R. A. Scott
Keyword(s):  
Rigid Body ◽  
Numerical Simulations ◽  
Dynamic Model ◽  
Experimental Model ◽  
Model Validation ◽  
Solution Method ◽  
Flexible Robot ◽  
Spherical Coordinate ◽  
Prismatic Joints ◽  
Rigid Body Motions

In [1] a dynamic model for flexible manipulators with prismatic joints and the solution method were presented. In this paper experiments on a spherical coordinate robot are performed to further validate the proposed dynamic model. Using the validated model, numerical simulations are performed to illustrate the coupling effects between the rigid body motions and the flexible motions, the effects of the flexible motion on a rigid body controller, and the effects of axial shortening.

Multibody System Dynamics Model Implementation in the Camshaft Engines

2005 ◽  
Author(s):  
Alexandre Mastaler ◽  
Gilson Arima ◽  
Alvaro Costa ◽  
Fabio Hildebrand Russo ◽  
Gerson Brand
Keyword(s):  
System Dynamics ◽  
Multibody System ◽  
Multibody System Dynamics ◽  
System Dynamics Model ◽  
Dynamics Model

Bayesian sensitivity analysis of flight parameters that affect main landing gear yield locations

2014 ◽  
Vol 118 (1210) ◽  
pp. 1481-1497 ◽  
Author(s):  
P. Sartor ◽  
K. Worden ◽  
R. K. Schmidt ◽  
D. A. Bond
Keyword(s):  
Sensitivity Analysis ◽  
Pitch Angle ◽  
Shock Absorber ◽  
Bending Moment ◽  
Landing Gear ◽  
Tube Bending ◽  
Vertical Descent ◽  
Margin Of Safety ◽  
Flight Parameters ◽  
The Individual

Abstract An aircraft and landing gear loads model was developed to assess the Margin of Safety (MS) in main landing gear components such as the main fitting, sliding tube and shock absorber upper diaphragm tube. Using a technique of Bayesian sensitivity analysis, a number of flight parameters were varied in the aircraft and landing gear loads model to gain an understanding of the sensitivity of the MS of the main landing gear components to the individual flight parameters in symmetric two-point landings. The significant flight parameters to the main fitting MS, sliding tube bending moment MS and shock absorber upper diaphragm tube MS include: longitudinal tyre-runway friction coefficient, aircraft vertical descent velocity, aircraft Euler pitch angle and aircraft mass. It was also shown that shock absorber servicing state and tyre pressure do not contribute significantly to the MS.

Simulation on Performances of Vertical Axis Wind Turbine

2010 ◽  
Author(s):  
Chien-Chang Chen ◽  
Cheng-Hsiung Kuo
Keyword(s):  
Wind Turbine ◽  
Pitch Angle ◽  
Vertical Axis ◽  
Flow Structures ◽  
Vertical Axis Wind Turbine ◽  
Ansys Fluent ◽  
Moment Coefficient ◽  
Pressure Distributions ◽  
The Moment ◽  
Starting Torque

This study employs the commercialized computational fluid dynamics software (Ansys/Fluent), with the user’s defined technique, to simulate the unsteady flow structures around the small-size vertical axis wind turbines (VAWT) with three straight blades. This study addresses the effects of the collective variations of the pitch angle (within ± 10°) on the performance of the VAWT system. The results of the transient (acceleration) stage will be employed to evaluate the self-starting ability. While the vertical axis wind turbine (VAWT) reaches a steady rotating stage, the detailed flow structures, the vorticity fields, the pressure distributions around, and the forces on the airfoils at various azimuthal positions will be addressed. For the blades with a negative pitch angle (θ = −10°), has the peak value of the moment coefficient within one revolution is the largest which will provide the largest starting torque to drive the VAWT system more easily. However, in this case, the moment coefficients are negative within some part of the period. This cancels part of the positive moment within one revolution, thus the efficiency is reduced at this pitch angle. For the case with positive pitch angle (θ = 10°), the area under the moment coefficient curve is the smallest and the time elapse of large moment coefficient is relatively short. Thus the efficiency and the starting torque are the lowest among thee pitch angles.

Analysis of the Sliding Contact Behavior of a Centrifugal Clutch

2016 ◽  
Vol 715 ◽  
pp. 231-236 ◽  
Author(s):  
Chih Hsing Liu ◽  
Yen Pin Chiang
Keyword(s):  
Experimental Data ◽  
Dynamic Model ◽  
Sliding Contact ◽  
Initial Contact ◽  
Maximum Output ◽  
Contact Behavior ◽  
Output Torque ◽  
The Difference ◽  
The Moment ◽  
Friction Lining

The analysis of the sliding contact behavior for friction lining is an important issue in design of centrifugal clutches. In this study, a numerical model based on the moment equilibrium and contact mechanics has been developed to analyze the dynamics of a commercial centrifugal clutch. The proposed dynamic model can estimate the rotational speed of initial contact, output torque, and contact pressure for friction lining during the clutch operation. The comparison of the numerical and experimental results for the output torque of the analyzed centrifugal clutch shows the simulation agrees well with the experimental data. The difference for the maximum output torque is around 1.9%, which shows the effectiveness of the proposed method. The proposed dynamic model can reduce unnecessary physical prototypes and experimental cost, and is expected to be used to improve the design of the centrifugal clutches.

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