Load Transmission Analysis Of Multi-Wheel And Multi-Strut Landing Gears

The multi-wheel multi-strut landing gear is developed from the first three-point landing gear.At present,the domestic research on this landing gear is still in the primary exploration stage,and mature technology has not yet been formed.Based on the independent development of China’s wide-body aircraft,the research and analysis of load distribution of multi-strut landing gear is carried out.Boeing 747-400 is taken as the research object in this paper.Based on the standards,a set of formulas for calculating the ground load of multi-strut landing gear is proposed,including symmetric landing,asymmetric landing,sliding brake and ground turning conditions.In addition,the load distribution of this multi-strut landing gear is analyzed under two landing conditions: symmetrical landing and rolling landing.In view of the problem that the load of the fuselage’s landing gear is too large under the symmetrical landing conditions at high angle of attack,the load distribution is optimized.The related strut technology is brought into consideration to analyse the influence of this technology on the load distribution of multi-strut landing gear.Then,the finite element model of the aircraft fuselage is established in the finite element software and the free modal is solved.The solution results are substituted into the simulation analysis software and combined with the rigid landing gear to form the whole aircraft rigid-flexible coupling model and the landing simulation calculation is obtained.The results are compared with the rigid model simulation results,and the empirical formula calculation results are compared with the simulation analysis results for further analysis.The analysis shows that,in the case of symmetric landing simulation,the load of the fuselage’s landing gear is much larger than that of the wing’s landing gear,and in the case of the left roll landing simulation,the load of left main landing gears is much larger than that of the right main landing gears.The gap between the main landing gears of the fuselage and the main landing gear of the wing can be reduced at the small angle by related strut technology.The flexibility of the fuselage can reduce the strut load of the landing gear.The calculated result of the formula and the simulation result of the rigid-flexible coupling model are in more consistence.Through the simulation analysis of multi-wheel multi-strut landing gear,this paper provides some experience and reference for the design of wide-body aircraft’s landing gear in the future,which lays a foundation for future research.