Interaction of torque link freeplay and Coulomb friction nonlinearities in nose landing gear shimmy scenarios

Rahmani, Mohsen; Behdinan, Kamran

doi:10.1016/j.ijnonlinmec.2019.103338

Cited by 28 publications

(22 citation statements)

References 31 publications

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“…Through the structure's torsional stiffness and torsional damping terms, the differential equation for the sliding tube torsion angle is linearly coupled to the shimmy damper torsion angle, and it is nonlinearly coupled to the structural lateral bending angle through the nonlinear forces and moments produced at the tire-ground contact. The differential equations for the torsional angles of the main fitting, the shimmy reducer, the sliding tube, and the lateral bending angle of the structure are given by equations (2-1) through (2)(3)(4).…”

Section: Mathematical Modeling Of Three Torsional Degrees Of Freedom ...mentioning

confidence: 99%

Influence of structural torsional degree of freedom on nose landing gear shimmy

Ding,

Feng,

Liu

et al. 2023

Preprint

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The structural characteristic of combining a maneuvering mechanism and a shimmy damper into a single component is present in the nose landing gear of large civil aircraft. Establishing a more accurate shimmy model based on this property is crucial. The three torsional degrees of freedom shimmy of the nose landing gear was mathematically and physically modeled. The time domain curve, spectrum diagram, and bifurcation diagram were used to compare the three torsional degrees of freedom shimmy model and the single torsional degrees of freedom shimmy model. The three-torsional freedom model predicts a greater amplitude and a longer convergence time in comparison to the findings of the single-torsional freedom model. The sliding tube's torsional vibration frequency falls from 10.9Hz to 8.1Hz in the three-torsional degree-of-freedom model, while the structure's lateral vibration frequency stays the same. The three-torsional freedom model predicts a decrease in the region of stable and torsional shimmy and an increase in the area of lateral and quasi-periodic shimmy. The amplitudes of all degrees of freedom in the three torsional degrees of freedom model, regardless of whether it is torsional or lateral, are greater than those in the single torsional degrees of freedom model when the vertical load is fixed. By increasing the torsional degrees of freedom of the shimmy damper and the main fitting, the inertia, stiffness, and damping in the torsional direction are redistributed in the three-torsional shimmy vibration model, which reduces the stability of the system.

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Section: Mathematical Modeling Of Three Torsional Degrees Of Freedom ...mentioning

confidence: 99%

Influence of structural torsional degree of freedom on nose landing gear shimmy

Ding,

Feng,

Liu

et al. 2023

Preprint

View full text Add to dashboard Cite

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“…The development of the drive train vibration monitoring system (VMS) to support the on-condition maintenance of V-22 tiltrotor mechanical components (rotors, blades, pylon shafts, nacelles) is discussed in [14]. The landing systems inspired a considerable interest for the study of the dynamic stability of the aircraft on ground, especially for shimmy and gear walk phenomena, [15][16][17][18][19][20][21][22][23][24][25]; on the other side, less literature references are found on the analysis of landing gears modal interaction with respect to the in-flight vibration spectra. In this sense, the present work provides novel key aspects on the dynamic response analysis to be considered during the development of propeller vehicles.…”

Section: Introductionmentioning

confidence: 99%

Vibration Response Analysis of a Main Landing Gear System for High In-Flight Dynamic Loadings

Arena,

Tartaglia,

Bruno

et al. 2024

J. Phys.: Conf. Ser.

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The prediction of aircraft vibrations is necessary for identifying possible design optimization points of each on-board system. In this context, the authors investigated the dynamic response of a Main Landing Gear (MLG) conceived for a fast helicopter when exposed to flight vibrations arisen from the engine propellers. The research activity falls within the Racer program of Clean Sky 2 framework, which aims to develop a novel high-speed rotorcraft. Relying on Airbus Helicopters operative requirements, this paper deals with the numerical procedure description of the MLG dynamic response assessment (resonance frequencies, accelerations amplitude, generalized masses) with respect to the expected in-flight vibrations levels. In particular, an equivalent combined load (sine and random spectrum) based on the normal modes and the corresponding modal mass distribution is employed for investigating the relevant effects on structural endurance. The central themes focus on the possible numerical modelling strategies and vibration loads analysis, which led safely to the qualification. This method could allow for performing sensitivity dynamic analyses in case of further design stiffness or weight changes.

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“…With the further research on shimmy analysis and modeling, the focus of current research has turned to the analysis of influencing factors of shimmy. Rahmani et al [1,7,8] studied the effects of coulomb friction and clearance connecting rods on the shimmy of the nose landing gear. Thota et al [9] studied the effect of changes in tire inflation pressure on the shimmy of the nose landing gear.…”

Section: Introductionmentioning

confidence: 99%

Investigation on the Effect of Anti-Braking System on Nose Landing Gear Shimmy

Zhang

Liu

et al. 2022

Advances in Transdisciplinary Engineering

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The influence of anti-braking system on the shimmy region and oscillation characteristics of the nose landing gear is studied. The moment generated by the braking system is modeled as a function of the adhesion coefficient and the torsional oscillation speed, and it is incorporated into the landing gear oscillation non-linear dynamic model. The results of analysis show that the braking frequency is increased by 50%, the area of the lateral dominant shimmy region is increased by 6.9%, the area of the torsional dominant shimmy region is reduced by 18.8%, and the amplitude of the torsional oscillation is suppressed. The braking amplitude is increased by 22%, the area of lateral dominant shimmy region is decreased by 3.1%, and the area of torsional dominant shimmy region is increased by 15.5%.

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Interaction of torque link freeplay and Coulomb friction nonlinearities in nose landing gear shimmy scenarios

Cited by 28 publications

References 31 publications

Influence of structural torsional degree of freedom on nose landing gear shimmy

Influence of structural torsional degree of freedom on nose landing gear shimmy

Vibration Response Analysis of a Main Landing Gear System for High In-Flight Dynamic Loadings

Investigation on the Effect of Anti-Braking System on Nose Landing Gear Shimmy

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