Nonlinear Dynamic Response Analysis of Aircraft Landing Gear with Finite Element Modeling

2016 ◽  
Vol 826 ◽  
pp. 23-27
Author(s):  
Wei Guo Wu ◽  
Zhen Tao Wang ◽  
Teng Jia
Keyword(s):  
Dynamic Response ◽  
Nonlinear Response ◽  
Shock Absorber ◽  
Landing Gear ◽  
Response Analysis ◽  
Nonlinear Fem ◽  
Fem Model ◽  
Nonlinear Dynamic Response ◽  
Aircraft Landing ◽  
Aircraft Landing Gear

The precise model and the analysis of nonlinear response are important for the landing gear research. In this paper, the FEM model of landing gear was established. The shock absorber is modeled with the nonlinear spring and damper. Random displacements were applied for simulating runway unevenness at aircraft taxiing. Through the simulation, the nonlinear FEM dynamic response of landing gear was acquired. The results show that: the stress of landing gear is large in the landing progress, especially for the random displacements; the weakness of landing gear is the axle sleeve. So the material and technology of the axle sleeve are important in the design of landing gear.

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.

scholarly journals Effects of Spring and Damper Elements in Aircraft Landing Gear Dynamics

2020 ◽  
Vol 8 (5) ◽  
pp. 4265-4269
Keyword(s):  
Shock Absorber ◽  
Impact Force ◽  
Landing Gear ◽  
Damping Coefficient ◽  
Aircraft Landing ◽  
Aircraft Landing Gear ◽  
Spring Coefficient ◽  
Mass Spring ◽  
The Impact

In this study a typical Aircraft Landing Gear with shock absorber was modeled a Mass-Spring-Damper System. Basic components of the system were explained. The equations of the model was presented. Aircraft Landing Gear was also modeled in Matlab/Simulink for a given set of aircraft parameters. A case study for an Aircraft Landing Gear was solved and results were presented. Results included the variation of spring (k1 and k2 ) and damping coefficient (b) in a given interval to show their effects on the impact force and displacement of landing gear as main outputs to consider. Effect of damping coefficient (b) on impact force was found to be highest (3.76%), spring coefficient (k1 ) effect is moderate (2.29%), and spring coefficient (k2 ) is lower (0.97%), for a change of ±10% of coefficients.

scholarly journals A New Design Model of an MR Shock Absorber for Aircraft Landing Gear Systems Considering Major and Minor Pressure Losses: Experimental Validation

2021 ◽  
Vol 11 (17) ◽  
pp. 7895
Author(s):  
Byung-Hyuk Kang ◽  
Jai-Hyuk Hwang ◽  
Seung-Bok Choi
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Pressure Loss ◽  
Shock Absorber ◽  
Landing Gear ◽  
Design Model ◽  
Pressure Losses ◽  
Aircraft Landing ◽  
Aircraft Landing Gear ◽  
Major Loss

This work presents a novel design model of a magnetorheological (MR) fluid-based shock absorber (MR shock absorber in short) that can be applied to an aircraft landing gear system. When an external force acts on an MR shock absorber, pressure loss occurs at the flow path while resisting the fluid flow. During the flow motion, two pressure losses occur: the major loss, which is proportional to the flow rate, and the minor loss, which is proportional to the square of the flow rate. In general, when an MR shock absorber is designed for low stroke velocity systems such as an automotive suspension system, the consideration of the major loss only for the design model is well satisfied by experimental results. However, when an MR shock absorber is applied to dynamic systems that require high stroke velocity, such as aircraft landing gear systems, the minor loss effect becomes significant to the pressure drop. In this work, a new design model for an MR shock absorber, considering both the major and minor pressure losses, is proposed. After formulating a mathematical design model, a prototype of an MR shock absorber is manufactured based on the design parameters of a lightweight aircraft landing gear system. After establishing a drop test for the MR shock absorber, the results of the pressure drop versus stroke/stroke velocity are investigated at different impact energies. It is shown from comparative evaluation that the proposed design model agrees with the experiment much better than the model that considers only the major pressure loss.

Multi-Domain Unified Modeling and Simulation for Aircraft Landing Gear Using Modelica

2011 ◽  
Vol 311-313 ◽  
pp. 2457-2460
Author(s):  
Ji Hong Liu ◽  
Ying Zhong Pang ◽  
Yu Ming Zhu
Keyword(s):  
Modeling And Simulation ◽  
Shock Absorber ◽  
Simulation Method ◽  
Heterogeneous Data ◽  
Landing Gear ◽  
Heterogeneous Platforms ◽  
Unified Modeling ◽  
Aircraft Landing ◽  
Aircraft Landing Gear ◽  
The Impact

Modern products become more and more complex, the modeling and simulation of them are carried out with different software on heterogeneous platforms, which always caused the heterogeneous data, separated disciplines and cannot obtain the result of unified model correctly. Therefore, a Modelica-based modeling and simulation method for aircraft landing gear is proposed. The landing gear library based on Modelica was established. The unified physical model of landing gear which is composed of structural, thermodynamics and hydromechanics disciplines is constructed. The aircraft landing process, the track of retraction mechanism and the impact work amount of the shock absorber are obtained through multi-domain unified simulation, which provides references for deisgners.

Optimization of a Semi-Active Shock Absorber for Aircraft Landing Gear

2003 ◽  
Author(s):  
Ken’ichi Maemori ◽  
Naoki Tanigawa ◽  
Reiko Koganei ◽  
Toshio Morihara
Keyword(s):  
Shock Absorber ◽  
Landing Gear ◽  
Second Step ◽  
Vertical Acceleration ◽  
Stepping Motor ◽  
Mass Variation ◽  
Orifice Area ◽  
Shock Absorbers ◽  
Aircraft Landing ◽  
Aircraft Landing Gear

We propose an optimization method for a semi-active shock absorber for use in aircraft landing gear, in order to handle variations in the maximum vertical acceleration of an aircraft during landing caused by the variation of the aircraft mass due to the variations in the number of passengers, and the amounts of cargo and fuel. In this optimization, the maximum vertical acceleration of an aircraft is set as an objective function to be minimized. Design variables searched in the first step of this optimization are discrete orifice areas formed by the outer surface of a hollow metering pin and a hole in the semi-active shock absorber. The design variable searched in the second step is a compensating orifice area which is controlled based on the mass variation. Using the optimum target orifice area obtained in the second step, we optimally determine a practical orifice area that is controlled by a stepping motor. The optimizations for a passive shock absorber and for semi-active shock absorbers with target and practical orifice areas indicate that the semi-active shock absorbers can handle aircraft mass variation much better than the optimum passive shock absorber. Furthermore, the robustness of the optimum practical orifice area controlled by a stepping motor is shown via simulation.

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