The Structure Optimization Of Forward-swept Composite Wing

Forward-swept wing has many advantages in aerodynamic characteristics, such as high critical Mach number, low wave drag and no wingtip stalling. But its torsion divergence problem is an obstacle for the application. Fortunately, aircraft designers can improve the low divergence speed problem of aircraft with forward-swept wing by means of composite aeroelastic tailoring technique.Firstly, in this thesis, the history and research status of the aircrafts with forward-swept wing was summarized, and the history of aeroelastic divergence problem was also reviewed. Then, the engineering method of the aeroelastic divergence and flutter problem and the aeroelastic part of the finite element software NASTRAN were also stated. Finally, the forward-swept wing model with X-29 as the reference was built, the influence to the divergence speed by angle of torsion of the 0°layers of composite laminate plates was probed.In this thesis, the forward-swept wing finite analysis and optimization model (more webs type wing and beam pumping wing), with the structure layout of X-29 and S-37's wings were established. It was required to satisfy the strength and flutter speed constraints. Then, the optimization model using the method of torsion of the whole composite laminate plates, was also built for optimizing the divergence speed. Meanwhile, the comparison between the optimization results of the two structure layouts was done.