Analysis of temperature effect on damping characteristics of landing gear shock absorber

2020 ◽  
Author(s):  
Ning Shu ◽  
Hongbin Gu ◽  
Hui Liu
Keyword(s):  
Temperature Effect ◽  
Shock Absorber ◽  
Landing Gear ◽  
Damping Characteristics

Procedure of training artificial neural network of elastic-damping characteristic control system of shock absorber landing gear struts of ground-based aircraft

2019 ◽  
Author(s):  
V.A. Brusov ◽  
Yu.Yu. Merzlikin ◽  
A.S. Menshikov
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Shock Absorber ◽  
Adaptive System ◽  
Landing Gear ◽  
Damping Characteristics ◽  
Wide Range ◽  
Artificial Neural ◽  
Run Up ◽  
Range Of Values

During their calendar life, passenger and transport aircraft run more than 200 thousand kilometers on the runways, which cause a significant part of the damage, both in the landing gears and in other units of the airframe. To reduce aircraft overloads at the stages of takeoff and landing (run-up and run on the runway) and taxiing, shock-absorbing struts with variable elastic-damping characteristics are used. Due to the fact that the parameters of the runway irregularities are in a wide range of values, it is necessary to use an adaptive system for controlling the stiffness coefficients and damping of the shock absorber strut, designed using an artificial neural network. The paper considered a network containing three layers. Using such a model, it is possible to implement an adaptive control circuit adjusting the elastic-damping parameters of the aircraft shock absorber struts to specific runway conditions (length and height of the irregularity, specific hardness of the runway). The velocity gradient method was used to train the artificial neural network. Half the square of the mismatch signal was used as the target criterion to be minimized. The calculated studies of the run up and run of the Il-114 aircraft on a dirt runway showed the possibility of reducing vertical overloads by up to 15% when equipped with a system controlling elastic-damping characteristics with a neural network. The comparison was carried out with an aircraft equipped with a “classical” (non-adaptive) system for controlling landing gear parameters.

Variation in Automotive Shock Absorber Damping Characteristics & amp; Their Effects on Ride Comfort Attribute and Vehicle Yaw Response

2021 ◽  
Author(s):  
Satyaranjan Sahoo ◽  
Eric Pranesh De Reuben ◽  
Deepak BAKSHI ◽  
Hari Krishnan ◽  
Amardeep Singh
Keyword(s):  
Shock Absorber ◽  
Ride Comfort ◽  
Damping Characteristics

scholarly journals Improving Vehicle Ride Response using a Shock Absorber with Dual Damping Characteristics

2011 ◽  
Vol 14 (AEROSPACE SCIENCES) ◽  
pp. 1-15
Author(s):  
M. Ajaj ◽  
A. Sharaf ◽  
S. Hegazy ◽  
Y. Hossamel-deen
Keyword(s):  
Shock Absorber ◽  
Damping Characteristics

A simulation investigation of helicopter ground resonance phenomenon

2019 ◽  
Vol 91 (3) ◽  
pp. 484-497
Author(s):  
Jaroslaw Stanislawski
Keyword(s):  
Simulation Method ◽  
Landing Gear ◽  
Rotor Blades ◽  
Resonance Phenomenon ◽  
Content Type ◽  
Damping Characteristics ◽  
Runge Kutta Method ◽  
Ground Resonance ◽  
Lumped Masses ◽  
Stiffness And Damping

Purpose The purpose of this paper is to present a simulation method applied for investigation of helicopter ground resonance phenomenon. Design/methodology/approach The considered physical model of helicopter standing on ground with rotating rotor consists of fuselage and main transmission gear treated as stiff bodies connected by elastic elements. The fuselage is supported on landing gear modeled by spring-damper units. The main rotor blades are treated as set of elastic axes with lumped masses distributed along blade radius. Due to Galerkin method, parameters of blades motion are assumed as a combination of bending and torsion eigen modes. A Runge–Kutta method is applied to solve equations of motions of rotor blades and helicopter fuselage. Findings The presented simulation method may be applied in preliminary stage of helicopter design to avoid ground resonance by proper selection of landing gear units and blade damper characteristics. Practical implications Ground resonance may occur in form of violently increasing mutual oscillations of helicopter fuselage and lead-lag motion of rotor blades. According to changes of stiffness and damping characteristics, simulations show stable behavior or arising oscillations of helicopter. The effects of different blade balance or defect of blade damper are predicted. Originality/value The simulation method may help to determine the envelope of safe operation of helicopter in phase of take-off or landing. The effects of additional disturbances as results of blades pitch control as swashplate deflection are introduced.

Characteristic Aircraft Landing Gear Thermo-Tribo-Mechanical Model

2012 ◽  
Author(s):  
Laurent Heirendt ◽  
Hugh H. T. Liu ◽  
Phillip Wang
Keyword(s):  
Mechanical Model ◽  
Structural Damage ◽  
Shock Absorber ◽  
Thermal Response ◽  
Landing Gear ◽  
Heat Sources ◽  
Sources And Sinks ◽  
Average Temperature ◽  
Aircraft Landing ◽  
Aircraft Landing Gear

A methodology for studying the characteristic thermal response of a landing gear (LG) shock absorber is presented. Rough runways induce high loads on the shock absorber bearings and because of high relative sliding speeds of the shock absorber piston, heat is dissipated which is known to have led to structural damage. In this work, an overall model has been developed that is used to outline the characteristics of the thermal behavior and identify the heat sources and sinks in the landing gear shock absorber. The developed thermo-tribo-mechanical model (TTM model) is subdivided into four parts, all using simplified but representative equations. Emphasis is placed on developing a methodological framework and studying the evolution of the average temperature in the TZI (thermal zone of interest) while taxiing and taking-off.

Research on Damping Properties of Seperated and Manually Adjustable Shock Absorber Oriented to Damping Matching

2013 ◽  
Vol 694-697 ◽  
pp. 36-40 ◽  
Author(s):  
Da Feng Song ◽  
Gong Ke Yang ◽  
Chun Xiao Du
Keyword(s):  
Mathematical Model ◽  
Structural Changes ◽  
Shock Absorber ◽  
Structural Parameters ◽  
Characteristic Curve ◽  
Bench Test ◽  
Damping Properties ◽  
Damping Characteristics ◽  
Test Use ◽  
The Mathematical Model

On the basis of the structure characteristics of the seperated manually adjustable damper and its working principles, establish the shock absorber mathematical model, at the same time, get test data and curves of seperated manually adjustable shock absorber damping characteristics by bench test. Use MATLAB to simulate the characteristic curve of the speed of the shock absorber based on the mathematical model. The simulation curves and experimental curves were compared to verify the correctness and accuracy of the model. Further simulation and analysis affect of parts of structural changes on the damping characteristics. In order to provide a theoretical basis to structural parameters designing and vehicle damping matching.

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.

scholarly journals A High-Efficiency Energy Harvesting By Using Hydraulic Electromagnetic Regenerative Shock Absorber

2020 ◽  
Author(s):  
Muhammad Yousaf Iqbal ◽  
Zhifei Wu ◽  
Khalid Mahmood
Keyword(s):  
Mathematical Model ◽  
Energy Harvesting ◽  
Shock Absorber ◽  
Mechanical Energy ◽  
Excitation Frequency ◽  
National Standard ◽  
Damping Force ◽  
Damping Characteristics ◽  
Simulation Results ◽  
Regenerative Shock Absorber

Abstract This article intends a hybrid energy harvesting shock absorber design which comprehends energy harvesting of automobile suspension vibration dissipation. A mathematical model of the energy harvesting prototype is established, and simulation results show that the dissipation energy can be recovered by varying the feed module, thereby got the damping forces ratio at different compression and extension stroke. The energy conversion from hydraulic energy to mechanical energy mainly then mechanical energy converted into electrical energy furthermore we can rechange our battery from this recovered energy. The advanced mathematical model and prototype proposed maximum ride comfort meanwhile recovered the suspension energy and fuel saving. This article shows the simulation results verifying it with prototype test results. The damping force of expansion stroke is higher than the damping force of compression stroke. The damping characteristics curves and speed characteristics curves verify the validity by simulation and prototyping damper at different amplitudes of off-road vehicles. The Hydraulic Electromagnetic Regenerative Shock Absorber (HESA) prototype characteristic is tested in which 65 watts recovered energy at 1.67 Hz excitation frequency. So, 14.65% maximum energy recovery efficiency got at 20 mm rod diameter and 8 cc/rev motor displacement. The damping characteristics of the HESA prototype examined and it has ideal performance as the standard requirements of the National Standard QC/T 491–1999.

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