Weight optimization of fixed landing gear for medium range UAV

Abstract

Weight reduction of Unmanned Aerial Vehicle (UAV) components and systems is one of the most essential factors for aviation. Takeoff gross weight can be divided into crew weight, payload, fuel, and empty weight. The empty weight is divided into the structure, engine/s, landing gear, avionics and fixed equipment. Engine/s, landing gear, avionics and fixed equipment are selective items. Weight optimization can be made for structure and landing gear to minimize aircraft total weight. The main objective of the present study is to optimize weight and reach safe landing for a medium range UAV landing gear. The reduced weight can be used to increase payload and/or fuel to increase range or endurance of the UAV. In the present study, ANSYS shape (Topology) optimization tool is used to get a proposed shape for the UAV landing gear. Then parametric size optimization of the shape proposed was done. Design of experiment (DOE) technique is used in order to get the minimum weight for the landing gear at a specified stress limit. Aluminum alloy 7075-T61 and bi-directional carbon fiber which are the most common used materials in UAVs landing gear were used, It was found that using topology weight optimization technique reduces Aluminum Alloy landing gear weight by (30.4 %) changing the material to be bi-directional carbon fiber without optimization reduce landing gear weight with additional value (27.9 %). Optimizing bi-directional carbon fiber landing gear reduces the weight with additional value (4 %) to be the total weight ratio by (62.3 %). The optimization technique for weight optimization is a guide to optimize any other type of landing / part to minimize the total weight for the Unmanned Aerial Vehicle.

A Novel Design and Structural Analysis of Spring Landing Gear for Unmanned Air Vehicles

“…3. yield strength of 503 MPa and an ultimate strength of 572 MPa was used as the landing gear material [24], [25]. The reason for using 7075-T6 Aluminum alloy material as the landing gear material was load life cycles, maximum static load capacity, optimal static strength and corrosion resistance.…”

“…However, as a result of loading 4140 N, FSS value was calculated as "1.45" in the new design landing gear. On the other hand, it was stated that the minimum stress safety factor value should be "1.5" according to the Federal Aviation Regulations (FAR) standards [25]. Therefore, the new design was not suitable for the minimum stress safety factor allowed for use under the 4140 N loading condition of the landing gear.…”