Design And Analysis Of Carbon Fiber Composite Drive Shaft Connection Structure For Heavy-duty UAV

The oil-driven heavy-duty UAV is a vehicle that has emerged in recent years,offering the advantages of high payload and convenience.Carbon fiber composites are a new material with high specific strength and modulus as well as excellent fatigue resistance.With these advantages,carbon fiber composite shafts are commonly used in all types of transport equipment on sea,land and air,and have an extremely broad application prospect.In heavy-duty UAV transmission systems,carbon fiber composite drive shafts need to be connected to metal components,and the strength of the connection structure will directly affect the performance of the transmission system,so the design of the connection structure is important.In this paper,a connection structure applied to the transmission shaft of oil-driven heavyduty UAV is designed and analyzed.Combining the thick-walled cylinder theory with composite mechanics,a theoretical analysis of the stresses on the carbon fiber composite drive shaft connection structure is carried out,and the basis for determining the failure of the connection structure and the carbon fiber composite tube is determined.By comparing the advantages and disadvantages of traditional connection methods,mechanical-bonding-tooth connection and mechanical-tooth connection are designed.The lap length,pin position and pin diameter were determined using both glued and mechanical design principles.The two connection structures were modelled using UG software and strength analysis was carried out using ANSYS to compare the analysis results and machining processes of the two structures.Based on the results of the analysis,the mechanical-toothed connection solution was finally chosen.Several sets of lay-up angles are selected to investigate the effect of lay-up angle on the torsional performance and drive shaft vibration of the joint structure.Based on the effect of layup angle on torsional capacity and the general design principles of composite laminates,four layup solutions are designed and simulated to investigate the effect of lay-up sequence on the carbon fiber composite joint structure.The final lay-up scheme is determined based on the analysis results.Four carbon fiber composite drive shafts were made according to the designed lay-up scheme and connection structure,and the above simulation results were verified by torsional experiments.The experiment results show that the designed connection structure and the chosen lay-up scheme meet the design requirements of the drive shaft of the oil-driven heavy-duty UAV and improve the torsional performance of the drive shaft to a certain extent.