Structural integrity aspects of a lightweight civil unmanned air vehicle

Abstract

Purpose The purpose of this paper is to focus on the finite element (FE) analyses undertaken for aerodynamically and structurally optimized design of a modern, lightweight civil unmanned air vehicle (UAV) made fully of composite materials. Design/methodology/approach The FE method has been applied to design and calculate the safety factors of all structural elements of the UAV. Fully parameterized design tools have been developed in the preliminary design phase, allowing automatic reshapes of the skin and the internal structural parts, wherever needed, to achieve optimal structural design, from the point of view of lightweight and structural integrity. Monotonic and fatigue tests have been performed on material specimens with various thicknesses and fibre textures, to verify the material properties used for the FE analyses. The load assumptions were in accordance with the valid international standards. Findings The material tests confirmed the validity of the material properties used within the FE calculations. The calculated safety factors were acceptable for all structural elements and components of the UAV. As a result, a lightweight, structurally optimized design has been achieved, considering the international, standardized specifications assumptions and fulfilling the safety requirements. Practical implications Design engineers may use the outcomes of this work as a guide to achieve optimal lightweight structures ensuring its operational strength using composite, lightweight materials. Originality/value A new, structurally optimized, lightweight aircraft design has been developed, able to accommodate heavy electronic payloads while being able to fly for over ten hours without refuelling. This medium altitude long endurance airplane can overview forests, seas and human trafficking autonomously and economically.