Computer simulation of the deformed state and strength of the frame structure of a heavy uav

Abstract

COMPUTER SIMULATION OF THE DEFORMED STATE AND STRENGTH OF THE FRAME STRUCTURE OF A HEAVY UAV The paper is devoted to the presentation of the computer simulation results of the stress-strain state and evaluation of the low-cycle strength of the frame structure of a heavy unmanned aerial vehicle (UAV) of the quadcopter type, the prototype of which was developed at NTU "KhPI". The quadcopter is built on the basis of the use of four internal combustion engines (ICE), which provide lifting power. The cycle of calculations of the stress-strain state of the frame structure, carried out to select the option required from the point of view of ensuring the required stiffness and strength, was performed using the Finite Element Method (FEM). A macro has been developed for use in the engineering software, which allows you to select the best parameters from the point of view of the required stiffness and strength of the frame. The results of calculations of the variant implemented in the design of the created UAV prototype are presented. According to the results of the analysis of the stress-strain state, it is shown that the structural parameters chosen for the steel frame of the prototype fully satisfy the conditions of minimal deformation and short-term strength. The constants included in the evolution equation for the damage parameter describing low-cycle loading, which occurs during UAV abnormal landings, have been determined. An elastic-plastic analysis of the frame structure deformation for the conditions of dangerous landing of the quadcopter was performed. Calculations of hidden damage accumulation processes in the most heavily loaded frame beams have been carried out. For the steel frame implemented in the created prototype, the possibility of satisfactory resistance to low-cycle deformation under abnormal landing conditions is demonstrated. It is shown that due to the insufficient low-cycle strength of the aluminum alloy structure, it is necessary to make structural changes in the new version of the UAV frame that is being designed. Key words: computer simulation, quadcopter, macro, beam structure, stress-strain state, FEM, low-cycle strength, damage.