Effect of noise reducing components on nose landing gear stability for a mid-size aircraft coupled with vortex shedding and freeplay

Eret, Petr; Kennedy, John; Bennett, Gareth J.

doi:10.1016/j.jsv.2015.06.022

Cited by 33 publications

(19 citation statements)

References 23 publications

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“…The bulk of shimmy studies account for the rotational-lateral dynamics only, assuming longitudinal DoF would only weakly couples with it (Van Der Valk and Pacejka, 1993; Thota et al., 2010; Eret et al., 2015), while the possibility of coupling has been confirmed in more recent works (Howcroft et al., 2013). Furthermore, the change in gear length due to the shock absorber compression affects the dynamics and structural characteristics (e.g.…”

Section: Fundamentalsmentioning

confidence: 99%

“…shimmy loads) being the number one cause (Lok et al., 2014). Accidents due to shimmy have been reported in the literature (Van Der Valk and Pacejka, 1993; CIAIAC, 1999; Eret et al., 2015), whose root cause commonly lays in inadequate design. It is crucial to prevent reoccurrence of such events through appropriate design decisions.…”

Section: Introductionmentioning

confidence: 99%

“…(2015) are also fifth-order. A dual-wheel NLG model was used by Eret et al. (2015) to study the effect of noise reduction apparatus on stability of the gear.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Investigation on the effect of coulomb friction on nose landing gear shimmy

Rahmani

Behdinan

2018

Journal of Vibration and Control

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Landing gear shimmy remains a challenge in aircraft design despite abundant advances in aircraft engineering in the past few decades. Accurate shimmy prediction is closely tied to availability of dynamic models with all relevant types of motions and key nonlinear elements, a matter which has been accomplished in the present study through including rotational, lateral, longitudinal, and axial degrees of freedom and tire, shock absorber, and Coulomb friction nonlinearities. Using multi-body dynamic simulations, stability of the nose landing gear is studied as a function of key system parameters. Influences of nonlinearities are investigated in isolation, with a more in-depth look at the Coulomb friction effect, which is modeled as a function of the shock absorber stroke rate and rotational shimmy speed. It is found that Coulomb friction is a key factor in determining the onset and type of shimmy. The effect of friction parameters is then studied using nonlinear sensitivity analyses, and witnessed trends are utilized to draw design recommendations.

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Section: Fundamentalsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Investigation on the effect of coulomb friction on nose landing gear shimmy

Rahmani

Behdinan

2018

Journal of Vibration and Control

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“…Such issues included the identification of appropriate attachment points on the landing gear, the potential for the physical interference of parts due to the kinematics as the landing gear folds away into the bay for stowage, and the deformation of the wheel tire upon touchdown of the aircraft. In addition, consideration of unexpected instability results, such as shimmy, due to the addition these add-ons needed to be considered [39].…”

Section: Effect Of Main Strut and Drag Stay On Wheel Well Noisementioning

confidence: 99%

Noise Characterization of a Full-Scale Nose Landing Gear

Bennett

Neri

Kennedy

2018

Journal of Aircraft

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This paper presents experimental results from a nose landing-gear test campaign. A highly detailed model of the nose section of a 90-seat configuration green regional aircraft concept was built and tested in an aeroacoustic open-jet wind tunnel at full scale. All of the landing-gear components, fixtures, and small details and associated structures such as the complete wheel bay, bay doors, and hydraulic dressings were included at full scale. This paper focuses on one element of the testing: that of component noise assessment. The dressings, wheels, torque link, steering pinion, bay doors, and then the main strut and drag stay were removed in succession, and an acoustic evaluation was performed at a range of velocities from M 0.12 to M 0.19. In addition, hub caps were installed on the wheels, and their performance as a low-noise treatment is presented and assessed for efficacy. The landing gear, doors, and bay generated most noise in the frequency range between 120 and 400 Hz, but appreciable noise above the baseline was measured up to 10 kHz. The low-to midfrequency aerodynamic noise was found to scale with V 6 , as usual; however, the spectra at high frequencies collapsed perfectly when scaled to V 7 , confirming the fact that high-frequency noise is radiated from the turbulent flow surrounding small features. The total noise output of the landing-gear assembly differs from that of the sum of the components in isolation due to installation effects. The research in this paper studied these effects and the influence of the components on each other.

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“…The uncertainty of the freeplay characteristics affects the interpretation of the bifurcation results. Eret et al. (2015) studied the freeplay in the torque link and found that it can cause shimmy over the typical operating conditions.…”

Section: Introductionmentioning

confidence: 99%

Analysis of dynamic mechanism and global response of vehicle shimmy system with multi-clearance joints

Junzhao

et al. 2016

Journal of Vibration and Control

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Joints with clearance always exist in steering mechanism of vehicles due to the machining tolerances, deformations and wear, which should not be neglected in modeling and analysis of vehicle shimmy system. Based on Lagrange equation method, a six-DOF dynamic model of vehicle shimmy system with consideration of multi-clearance joints was established. The model of movement pairs with clearance was built based on Hertzian contact law. The nonlinear cornering force of pneumatic tire was described based on PAC2002 tire model, and its parameters were obtained by an identification method based on experimental data. Then numerical examples were employed to evaluate the dynamic response of the shimmy system. The influence of multi-clearance joints on the response of shimmy was analyzed, and it is compared with that of one clearance joint. The acting mechanism of contact force between movement pairs was investigated, and global dynamic analysis was carried out by using point mapping method. Moreover, the dynamic mechanism for vehicle shimmy was investigated based on energy input. The conclusions can provide theoretic evidence for attenuation of vehicle shimmy, especially for those in-service vehicles.

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Effect of noise reducing components on nose landing gear stability for a mid-size aircraft coupled with vortex shedding and freeplay

Cited by 33 publications

References 23 publications

Investigation on the effect of coulomb friction on nose landing gear shimmy

Investigation on the effect of coulomb friction on nose landing gear shimmy

Noise Characterization of a Full-Scale Nose Landing Gear

Analysis of dynamic mechanism and global response of vehicle shimmy system with multi-clearance joints

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