Parametric Analysis on Landing Gear Strut Friction of Light Aircraft for Touchdown Performance

Shengyong Gan,Xingbo Fang,Xiaohui Wei

doi:10.3390/app11125445

Shengyong Gan, Xingbo Fang + Show 1 more

Open Access

https://doi.org/10.3390/app11125445

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Abstract

The aim of this paper is to obtain the strut friction–touchdown performance relation for designing the parameters involving the strut friction of the landing gear in a light aircraft. The numerical model of the landing gear is validated by drop test of single half-axle landing gear, which is used to obtain the energy absorption properties of strut friction in the landing process. Parametric studies are conducted using the response surface method. Based on the design of the experiment results and response surface functions, the sensitivity analysis of the design variables is implemented. Furthermore, a multi-objective optimization is carried out for good touchdown performance. The results show that the proportion of energy absorption of friction load accounts for more than 35% of the total landing impact energy. The response surface model characterizes well for the landing response, with a minimum fitting accuracy of 99.52%. The most sensitive variables for the four landing responses are the lower bearing width and the wheel moment of inertia. Moreover, the max overloading of sprung mass in LC-1 decreases by 4.84% after design optimization, which illustrates that the method of analysis and optimization on the strut friction of landing gear is efficient for improving the aircraft touchdown performance.

Highlights

The aircraft landing gear plays a crucial role in the takeoff, landing impact energyabsorbing, and ground operations [1]
To improve the landing performance by designing friction in the strut, a dynamic model of the landing gear needs to be established to obtain the effect of friction load on the soft landing buffering; it is required for the designer to determine the influence of landing gear structure parameters on strut friction
The results show that the proportions of energy absorbed by friction are more than 35% in two landing conditions: 38.15% and 35.76%

Summary

Introduction

The aircraft landing gear plays a crucial role in the takeoff, landing impact energyabsorbing, and ground operations [1]. In the shock absorber strut, the friction force is an elemental force of the total strut force and converts kinetic energy into internal energy in the landing process [2]. Friction can affect landing performance, especially in the light aircraft landing gear [3], which has a smaller structure stiffness and total strut force. To improve the landing performance by designing friction in the strut, a dynamic model of the landing gear needs to be established to obtain the effect of friction load on the soft landing buffering; it is required for the designer to determine the influence of landing gear structure parameters on strut friction. The dynamic modeling and analysis of a landing gear with an oleo-pneumatic shock absorber has received relatively large attention in the literature [4,5,6]. The analysis model with sprung and unsprung mass vertical degrees of freedom is established in Milwitzky [7]

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