The Desige And Optimization Of Superelastic Flexible Honeycomb Structure

In recent years, intelligent morphing aerospace has become one of the important developing directions of the aircraft. The aircraft skin is used to transfer the aerodynamic load to components inside the aircraft. With the development of vehicle, the deformation and aircraft skin proposed some new requirements, such as light weight, flexible and continuous deformation, high stiffness, etc.The wing skins of the morphing aircraft would be highly anisotropic with low in-plane extending stiffness to fit the wing transformation and high out-of-plane bending stiffness to undergo the aerodynamic loads. A material mechanics method is presented to evaluate the elastic modulus properties of the U-shape honeycomb structures. The U-shape honeycomb structures were proved to have low in-plane axial stiffness and good load resistance in other directions. Both finite element analysis and experimental tests were carried out to verify the accuracy of the proposed analytical formulation. And a theoretical analysis solution also was developed, which could well compare with both experimental results and FEA results. It was also substantiated that U-shape honeycomb structures could be used for morphing aircraft wing skins.This paper derived a formula to calculate the coplanar elastic modulus of a superelastic honeycomb structure under the assumption of small deformation by energy method. As is shown in the theoretical calculation, finite element simulation and experimental test, the equation has high accuracy. Finally, we discuss the relationship between the structural parameters of honeycomb core and coplanar equivalent modulus, which provides a reference for design and optimization for this superelastic honeycomb structure.A brief introduction of the two kind of honeycomb with negative possion is also taken. Using the energy method ,a formula about the mechanical parameters of the honeycomb is obtained. The optimal solution is obtained by optimization toolbox of MATLAB. The experimental samples is manufactued and tested to verify the characteristics of the cellular...