In this work, a six degrees of freedom heave-pitch mathematical model has been developed for an aircraft with main and nose oleo-pneumatic landing gear. Nonlinearities in stiffness, damping, and bending characteristics of landing gears and tires are incorporated in the model. Friction is an incidental and inevitable reaction that sticks along with the strut motion during the event of ground contact. The friction generated in the landing gear is the sum of the contribution from bearings and seals fitted in the landing gear. This study has focused on investigating the amount of frictional resistance gained by the struts while an aircraft is landing at various sink rates. The strut vertical forces, seal friction forces, and bearing friction forces generated in the main and nose landing gear during touchdown have been presented in this work. This preliminary estimation of friction forces for a range of sink rates aids the designer in developing optimal geometric or strut parameters in the design stage. This work also helps to calculate total landing loads for the certification of the landing gear.

在这项工作中，已经为具有主和机头油压气动起落架的飞机开发了一个六自由度升沉-俯仰数学模型。模型中包含了起落架和轮胎的刚度、阻尼和弯曲特性的非线性。摩擦是一种偶然的和不可避免的反应，在接触地面的情况下会随着支柱运动而发生。起落架中产生的摩擦力是安装在起落架上的轴承和密封件的摩擦力之和。这项研究的重点是调查当飞机以不同的下沉率着陆时支柱获得的摩擦阻力量。本工作介绍了接地期间主起落架和前起落架中产生的支柱垂直力、密封摩擦力和轴承摩擦力。对一系列下沉率的摩擦力的初步估计有助于设计人员在设计阶段开发最佳几何或支柱参数。这项工作还有助于计算起落架认证的总着陆载荷。