Structural Design Analysis Torque Links of Nose Landing Gear on Light Aircraft

Abstract

Torque links are components of Nose Landing Gear on the designed lightweight aircraft, that connect between the inner and outer cylinders of an oleo-pneumatic shock strut. They prevent torsion or twisting between those components and vibrations at retractable nose landing gear, the safety of these components is very important, especially when landing aircraft. This paper studies the stress and deformation contours of the torque link design with variations of hole geometry to get the optimal design, with the lightest possible weight but still reliable and safe. The upper torque link is modeled as a simply supported beam with a moment on one end derived from impact force when landing. Maximum bending stresses occur in areas near holes and the connection part of the torque link. This analysis with a tetra mesh by changing the hole position and geometry. The final torque link design results in a weight reduction of up to 23.75% with a maximum stress is 157.4 MPa and displacement is 0.0166 mm. Torque link design optimization results are then modally analyzed, and four natural frequencies and the mode shape are done. The natural frequency of vibration of different mode shapes obtained ranges from 4.2259 kHz to 6.1319 kHz, and this is still below the limit of 0.1 kHz (around 6,000 rpm engine). Finally, the optimal design torque links were obtained, safe from static and dynamic loads with a Factor of Safety 1.78 (>1.5) according to the FAR-23 standard.