Nonlinear dynamic response of aircraft nose-landing gear shimmy vibration /
Shimmy, an oscillatory motion in torsional and lateral directions of landing gear, occurs usually on aircraft on the ground during landing, takeoff or taxi. The shimmy motion is due to dynamics interaction between the landing gear system and the tire. The vibration was induced by many factors such a...
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| Format: | Thesis |
| Language: | English |
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| Online Access: | http://studentrepo.iium.edu.my/handle/123456789/5019 |
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| Summary: | Shimmy, an oscillatory motion in torsional and lateral directions of landing gear, occurs usually on aircraft on the ground during landing, takeoff or taxi. The shimmy motion is due to dynamics interaction between the landing gear system and the tire. The vibration was induced by many factors such as structural and non-structural combination of mass, damping, elastic stiffness, speed excitation forces, geometrical quantities, and nonlinearities such as free play and friction. It usually occurs within the range of frequency of 10 – 30 Hz most commonly in nose landing gear which can appear in the longitudinal, lateral and yaw directions. The shimmy can be induced also by asymmetric conditions occurring at landings with prevailing crosswind. Most of the study works on small perturbation assumption where the vibration occurs in small vibration. In the present work, a nonlinear, coupled dynamic shimmy model oscillation is proposed for nose landing gear. The dynamic model is based on the shimmy model of Thota and is extended in the present thesis by considering large deformation in bending and torsional displacement. The project is focusing on a free rolling scenario of a common mid-size commercial passenger aircraft. The influence of different vibrational modes on the landing gear dynamics is highlighted. Three vibrational modes are considered in this thesis. The modes are torsional mode, lateral bending mode and longitudinal bending mode. The torsional mode corresponds to the rotation about the gear strut axis while the lateral bending mode represents vibrations of the gear from left to right and the direction of straight-line travel of the aircraft is the longitudinal bending mode. The three modes of vibration are coupled through the geometry of the gear and through the force generated at the tire-ground contact. It is found that their nonlinear interaction plays a significant role in aircraft landing gear shimmy dynamics. |
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| Physical Description: | xiv, 76 leaves : colour illustrations ; 30cm. |
| Bibliography: | Includes bibliographical references (leaves 66-70). |