Dynamic study of aircraft gear behaviour in some unusual conditions

Journal of KONES, 2006

The paper presents the example of MCAD and CAE environments integration in the case of the military transport aircraft front gear dynamic analysis. The gear exact MCAD model is presented with the manner of its simplification. Simplified model is physically similar to the exact one: results of numerical static analysis are the same in both cases. To ensure the credibility of the dynamic analysis, a model kinematics one took place-the gear configuration changed ("airborne"-"airfield") with the measurements of chosen values. Simulation was verified with the real experiment results. The gear drop test has been simulated with the measurement of the fall-down velocity and absorber displacement. By the progressive results comparison of digital and real experiments, the stiffness-dumping values were attached to the spring/dumper Lagrange elements that simulate the behavior of the absorber gas-oil mixture. The gear model shock sensitivity has been analysed by simulations of landing process with gear invasion through chosen airfield obstructions. Aircraft fall-down velocity can be safely increased by 30% and it can operate on slightly damaged concrete airfields and rough surfaces. The shimmy vibration model sensitivity took place. It is proved that such a phenomenon can't appear during the correct aircraft maintenance.

DS 30: Proceedings of DESIGN 2002, the 7th International Design Conference, Dubrovnik, 2002

An experimental and analytical investigation was conducted to determine which characteristics of a light aircraft landing gear influence gear dynamic behavior significantly. The investigation focused particularly on possible modification for load control. Pseudostatic tests were conducted to determine the gear fore-and-aft spring constant, axial friction as a function of drag load, brake pressure-torque characteristics, and tire force-deflection characteristics. To study dynamic tire response, vertical drops were conducted at impact velocities of 1.2, 1.5, and 1.8 m/s onto a level surface; to determine axial-friction effects, a second series of vertical drops were made at 1.5 m/s onto surfaces inclined 5 deg and 10 deg to the horizontal. An average dynamic axial-friction coefficient of 0.15 was obtained by comparing analytical data with inclined surface drop test data. Dynamic strut bending and associated axial friction were found to be severe for the drop tests on the 10 deg surface.

A computer aided graphical synthesis was undertaken to understand the kinematics of a nose wheel landing gear mechanism such as that on the Lockheed F-16 using Working Model software. The mobility of the design was verified by computer animation. To contrast the nose gear kinematic simulation, the main landing gear located under the wing of a light weight aircraft such as the Berkut (Ber-koot) was also studied. The Berkut is the product of Experimental Aviation, Inc. (E.A.I) located in Santa Monica, California. This plane was selected because it is representative of the growing market of kit and light weight general aviation aircraft in the 1,000 to 2,000 pound weight range. In this weight class, the Solid-Spring landing gear can be used instead of the oleoshock-strut type used in the F-16. Computer modeling and finite element analysis are explored to analyze stresses developed while landing at normal sink rates. The deflections of the main spring gear are calculated and the interna...

International Journal of Engineering Research and, 2015

The landing gear system of an aircraft is a system. It also absorbs the energy from the impact of landing Numerical type simulation has become highly invaluable tool for the assessment of the landing gear type dynamics also as well as of aircraft landing structure gear interaction. This paper also describes the normal structure review of a simple landing-gear structure model system, and which is accurately simulates with the energy system absorbed by the gear without the adding substantial structure and complexity with the model. it carries the structure aircraft weight at all require ground operations, including, landing, take off, taxiing, and towing. In future we know that advances in computational type speed have made aircraft and high spacecraft crash simulations design using an explicit, transient type dynamic, finite element analysis (FEM) code are the more feasible. For a plane crash model type system the landing gear is also exact response is approximated work with a many strong spring where many different force applied to the different fuselage. And it is also computed in a userwritten works type. Helicopter crash type simulations which is using this approach that are compared with different necessary data is also acquired with the experimental method and data from a full structure crash structure test can be achieved by with the use of an aircraft of a composite. Depends on type of landing gear systems is also presented. Specifically, a nonlinear type model can easily developed which is simulated, and against static and dynamic data test data. Many type model includes nonlinear structure effects such as a velocity type squared related high damping, poly tropic gas law, stick-slip friction, a geometry governed with the high model structure for the high discharge type coefficients and methods, effects a nonlinear spring and damping model structure.

1997 Annual Conference Proceedings

A computer aided graphical synthesis was undertaken to understand the kinematics of a nose wheel landing gear mechanism such as that on the Lockheed F-16 using Working Model software. The mobility of the design was verified by computer animation. To contrast the nose gear kinematic simulation, the main landing gear located under the wing of a light weight aircraft such as the Berkut (Ber-koot) was also studied. The Berkut is the product of Experimental Aviation, Inc. (E.A.I) located in Santa Monica, California. This plane was selected because it is representative of the growing market of kit and light weight general aviation aircraft in the 1,000 to 2,000 pound weight range. In this weight class, the Solid-Spring landing gear can be used instead of the oleoshock-strut type used in the F-16. Computer modeling and finite element analysis are explored to analyze stresses developed while landing at normal sink rates.

Journal of KONES, 2009

The FEM model of the landing gear was developed to determine efforts of individual structural members while simulating the landing-gear drop, and to investigate how the energy of such a system changes; also, to find what kinds of deformations occur in individual components, and to investigate into the effectiveness of the damping system. In the developed numerical model of the landing gear account was taken also of the support-wheel-related subassembly, which includes such elements as: the wheel pin, the wheel rim, and the tyre. All parts of this subassembly, belt in the tyre excluded, were represented with the flexible hexagonal elements. Results of numerical analyses for some selected drop tests and results from experiments carried out on a real landing gear confirm high quality of results gained from the dynamic simulation in the model of a complete landing-gear configuration. The advantage of the presented numerical method is applicability thereof to landing gear testing for the...

International Journal of Scientific Research in Science and Technology, 2022

An aircraft landing gear system must absorb the kinematic energy produced by a landing impact and excitations caused by the aircraft travelling over an uneven runway surface. This is necessary requirement of successfully designed landing system. The oleo pneumatic shock is the most common type of shock absorber landing gear system used in aircraft. It dissipates the kinetic energy produced by impact arising when an airplane lands at high speed but also offer a comfortable rice to passenger when the airplane taxies at low speed. The objective of this project to determine the stress behavior and the displacement of a nose gear of an aircraft during landing using structural finite element analysis using with the help of analytical calculation. The external forces were determine analytical and the interactions between components were carefully modeled using contact analysis.

2013 International Conference on Machine Intelligence and Research Advancement, 2013

In this article, the delamination onset and growth behavior of double cantilever beam (DCB) specimens has been presented. The modeling of a debonded region using master and slave surface technique for DCB specimens is done in ABAQUS CAE. The analysis of DCB specimens comprising of fatigue cyclic load has been done in ABAQUS. An onset and Paris delamination growth regimes are plotted. The growth regime being linear in log-log scale, the prediction of constants of this regime has been obtained using the polyfit command in the MATLAB environment. To obtain these constants has been explained in this article. Comparison of experimental and analytical results is shown for delamination growth. The strain energy release rate values for threshold and critical are indicated on the graphs. The number of cycles for delamination onset and growth has been tabulated for various load cases.

Frattura ed Integrità Strutturale

In this paper, a new methodology supporting the design of landing gears is proposed. Generally, a preliminary step is performed with simplified FE model, usually one-dimensional, to achieve the reaction forces involving each component during all aforementioned aircraft operations. Though this approach gives a valid support to the designer, it is characterized by several problems, such as the related approximations. So, it is important, by a numerical point of view, to develop an isostatic FE model equivalent to the real one. In fact, if the landing gear is modelled as hyperstatic, the static equilibrium equations are insufficient for determining the internal forces and reactions on each sub-component; so, the modelled material properties and geometries assume an increasing importance, which gets the model too approximating. The proposed methodology consists of achieving the reaction forces by means of multibody simulations, by overcoming such problems, since each component is modell...