Longitudinal Instability in Braked Landing Gear

1981 ◽  
Vol 103 (3) ◽  
pp. 259-265 ◽  
Author(s):  
R. R. Allen ◽  
R. C. O’Massey
Keyword(s):  
Mathematical Model ◽  
Steady State ◽  
Analytical Methods ◽  
Design Guidelines ◽  
Landing Gear ◽  
Nonlinear Mathematical Model ◽  
Nonlinear Characteristics ◽  
Aircraft Landing ◽  
Design Variables ◽  
Aircraft Landing Gear

An instability in the form of a self-excited, bounded longitudinal oscillation may occur in aircraft landing gear when one or more wheels lock due to excessive braking. The instability usually appears at ground speeds below 40 knots (20 m/s) and results from interaction between structural elasticity and the nonlinear characteristics of tire-runway friction. A nonlinear mathematical model is developed to study the dynamics of this divergence in a braked, dual tire landing gear. Analytical methods are presented to determine critical ground speeds in terms of runway friction characteristics and to predict the amplitude of steady-state oscillations. The effect of design variables on longitudinal stability is evaluated and design guidelines are presented which insure reduction of the severity of this divergent dynamic behavior.

scholarly journals 1002 Aerodynamic noise reduction for aircraft landing gear

2009 ◽  
Vol 2009 (0) ◽  
pp. 321-322
Author(s):  
Kazuhide Isotani ◽  
Kenji Hayama ◽  
Akio Ochi ◽  
Toshiyuki Kumada
Keyword(s):  
Noise Reduction ◽  
Landing Gear ◽  
Aerodynamic Noise ◽  
Aircraft Landing ◽  
Aircraft Landing Gear

A Hybrid Expert System–Nonlinear Programming Approach to Optimal Gear Design

1989 ◽  
Author(s):  
K.-C. Lin ◽  
G. E. Johnson
Keyword(s):  
Mathematical Model ◽  
Expert System ◽  
Spur Gear ◽  
Design Guidelines ◽  
Geometric Design ◽  
Geometric Constraints ◽  
Programming Approach ◽  
Gear Design ◽  
Design Variables ◽  
Short Period

Abstract An expert system is developed for optimal spur gear design. Design automation is accomplished by dividing the design variables into different categories, i.e. geometric design variables and non-geometric design variables. The geometric variables are further divided into terms that are related to the gear mathematical model and terms that are determined according to the designer’s experience. By properly developing the mathematical model, numerical optimisation can be used to seek the best solution for a given set of geometric constraints. The process of determining the non-geometric design variables is automated by using symbolic computation. This gear design expert system is built according to the AGMA standards and a survey of gear design experts. The recommendations of gear designers and the information provided by AGMA standards are integrated into knowledge bases and data bases. By providing fast information retrieval and design guidelines, this expert system greatly streamlines the spur gear design process and makes it possible for a novice designer to achieve a reliable design in a short period of time.

Nonlinear Transient Analysis of Aircraft Landing Gear Brake Whirl and Squeal

1995 ◽  
Author(s):  
Matt H. Travis
Keyword(s):  
Finite Element ◽  
Transient Analysis ◽  
Landing Gear ◽  
Friction Modeling ◽  
Explicit Integration ◽  
Aircraft Landing ◽  
Aircraft Landing Gear ◽  
Nonlinear Transient ◽  
Element Approach ◽  
Stiffness And Damping

Abstract The feasibility of computing non-linear transient finite element simulations of aircraft landing gear brake whirl and squeal is demonstrated and discussed. Methodology to conduct the high frequency brake transient analysis is developed using an explicit integration finite element approach. Results indicate the approach has the capability to simulate brake dynamic behavior in dynamometer and aircraft landing gear installations — thus enabling evaluation of modifications to braking systems that lead to more stable and robust designs. A simple multi-disk brake model is developed and described. Modeling techniques for including the dynamometer road wheel and runway in the simulations are given. Issues such as piston housing hydraulic fluid stiffness and damping effects, and parametric friction modeling are discussed.

Study on Magneto-rheological Damper Control of Aircraft Landing Gear Based on LADRC

2021 ◽  
pp. 830-840
Author(s):  
Lei Dong ◽  
Zengqiang Chen ◽  
Mingwei Sun ◽  
Qinglin Sun ◽  
ZhenPing Yu
Keyword(s):  
Landing Gear ◽  
Aircraft Landing ◽  
Aircraft Landing Gear ◽  
Damper Control ◽  
Magneto Rheological
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