On the modeling of light aircraft landing gears

International audienceLight aircrafts are designed to be used in both developed and undeveloped areas of a country. Hard landingconditions such as shocks and rebounds may occur. In this context, a good, efficient, robust and easy to maintainlanding gear is vital. Its main role is to dissipate the energy of the impact. The aim of this work is to study aninnovative light aircraft landing gear equipped with a damper. The study includes comparing its dissipationperformance with two traditional light aircraft landing gears: a classical flat spring landing gear and a landing gearwith Sandow cords. These systems’ modeling is carried out through three steps. Firstly, Bush tire is modeled withfinite elements considering tire geometry and material specificities. Secondly, combined finite elements withstructural elements are used to model the different landing gear systems. Thus, stress, deformation and energywithin landing gears components could be obtained. Finally, aircraft rolling simulations are conducted. Systems’transient responses while rolling over ramp are evaluated, as well as the efforts and rebound displacementstransmitted to the aircraft. A dissipation efficiency comparative study between the landing gears is conducted. Inaddition, the influence of simulation’ conditions such as inflation pressure, rolling velocity or runway flatness isinvestigated

Thermo-viscoelastic modeling of the aircraft tire cornering

International audienceSome numerical models are proposed for simulate the aircraft tire behaviour on the ground in critical situations. Fully coupled thermo-mechanical analysis procedures taking into account finite deformation, dynamics and frictional contact are studied; the visco-elasticity properties of the rubber were identified. A good agreement is observed at moderate speed, thus the model is extrapolated to high speeds and seems able to predict results in cases for which it is not possible to obtain realistic experimental data. In order to understand the thermal evolution of tire tread rubber materials during rolling and skidding steps, new experimental and numerical studies were also realized on tire tread rubber. The aim of this approach is to simulate and understand the effect of frictional heating on the tire behaviour

Finite Element Modeling of an Aircraft Tire Rolling on a Steel Drum: Experimental Investigations and Numerical Simulations

International audienceThe aim of this study is to investigate the thermal evolution of an aircraft tire rolling at high velocities up to take off values. As this kind of experiment is difficult to realize on a real runway, experimental tests were realized on aircraft tires rolling on a steel drum. The rotating drum facility allows to apply variable velocities beyond the take off limits, at fixed skidding angles and loadings. The rolling conditions, vertical loading, velocity and cornering conditions were adopted to correspond to the real conditions of an aircraft tire running or skidding on a flat runway. In the experimental part, the influence of skidding angle, velocity and loading on the thermal evolution of the tire tread were investigated. The thermo-mechanical finite element analysis of a pneumatic radial tire structure was performed taking into account the hyper-viscoelastic rubber behavior, with heating mechanisms developed by the inelastic deformation and by friction. Three-dimensional finite element simulations of an aircraft tire rolling on a steel drum were carried out using Abaqus/Standard finite element solver. The comparison of the temperature distribution on the tire tread between numerical results and the experimental data shows the same overall tendencies. The good correlation between numerical and experimental data shows that numerical simulation could predict the thermal evolution of the tire in critical situations. The authors would like to mention that for confidentiality reason, certain numerical data could not be revealed

On the performance of light aircraft landing gears rolling on different types of runway

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Étude du comportement en roulement sur piste accidentée d'un pneumatique d'avion léger

International audienceCe travail présente un aperçu du comportement des pneumatiques d'avion de brousse et de leurs caractéristiques. Un modèle numérique éléments finis des pneumatiques est développé où leurs spécificités matérielles et géométriques sont pris en compte. Des simulations de roulement sur des rampes sont réalisées et montrent la déformation importante subie par ce pneumatique lors de la rencontre avec un obstacle ainsi que sa faible rigidité latérale qui lui confèrent une capacité importante à absorber les chocs. Des simulations en dérapage ont permis d'évaluer le moment d’auto-alignement

On the performance of light aircraft landing gears rolling on different types of runway

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Characterization and Simulation of a Bush Plane Tire

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