Mechanical and material designing of lightweight high endurance multirotor system

Abstract

Abstract Multi-rotor system (MRS) designing and material selection methodology for a light weight composite sandwich to increase endurance and payload is presented in this paper. The design outline is created with parameters such as geometrical dimensions, cruise speed, payload, and endurance. These parameters are optimised by defining design equations, corresponding to the specifications of commercially off-the-shelf multi rotors. To address material assessment, sandwich composites are designed to fabricate the intended MRS. The material performance indices of the core and facesheet are evaluated using Ashby plots. The results demonstrated core materials; RohaCell, DivinyCell, Airex, Balsa Wood; and facesheet materials; carbon/glass epoxy composite, to develop a robust light-weight sandwich composite. The tensile strength, flexural strength, density and price per unit volume are evaluated, which presented balsa wood with stiffer, light-weight and economical characteristics to develop composite with required properties. A finite element model is implemented to capture bending and tensile test results on balsa carbon/balsa glass-epoxy composite. The investigation presented 35.19% and 33.33% higher flexural and tensile strength in lighter carbon fibre-based composite sandwich than glass-based. The carbon balsa sandwich composite absorbs 2.510 MJ/mm3 and 2.569 MJ/mm3 more energy in tensile and flexural actions than glass balsa sandwich composite. Conclusively, carbon balsa sandwich composite is fabricated using vacuum assisted wet lay-up method (VAWLM), which inherently helps to reduce inter-ply voids. A total of fifteen test flights indicated average endurance time of 28.3 min and average payload of 308 g for the fabricated MRS.