Design Of Negative Pressure Folding Wing And Mechanical Properties Of Study

Smart aircraft need to make transportation and storage more convenient under the conditions of basic use.Therefore,more and more aircraft choose to use the structure of folding wings,which can reduce the volume of the aircraft,facilitate transportation and storage,and provide sufficient lift for the aircraft when expanded.This thesis,which is based on the research status and development trends of folding wing expansion schemes at home and abroad,proposes a new type of "negative pressure folding scheme" and focuses on its mechanical performance analysis.This thesis firstly compares and analyzes the domestic and foreign research schemes of folding wings.Based on the functional requirements of folding wings structure,a "negative pressure folding scheme" is proposed,its working principle and construction scheme is given,and its structural composition is analyzed.Its key dimension parameters are designed,and this thesis optimizes its internal structure and connection mode,determines the structural composition of the negative pressure folding wing,and theoretically calculates the degree of vacuum required for its expansion.The failure mode and influence analysis(FMEA)of the folded wing structure was carried out.The possible failure modes and the consequences after failure were given,and compensation measures were offered.The material of the wing body is selected,according to the airfoil design,the main shape of the folded wing is processed and the feasibility of unfolding is verified through the unfolding test.Three-point bending and cantilever beam mechanical performance tests were performed separately on the folded wings.Through the above tests were performed by finite element calculations respectively,the mechanical performance tests were in good agreement with the results of the finite element calculations,which verified the rationality and correctness of the negative pressure folding wing expansion scheme.At the same time,the finite element simulation was used to calculate the limit load that the folded wing can withstand under two conditions of different vacuum degrees,which realized the mechanical performance evaluation of the negative pressure folded wing.The significant meaning of this thesis is to serve as reference for the design of negative pressure folding wings for smart UAV.