Study On The Design And Mechanical Performance Of Cfrp Truncated Conical Sandwich Structure With Origami Core

In the field of aerospace,adapter is a primary structure of commercial rocket providing the interface between a rocket and a spacecraft.In the past decade,people has paid more attention to Origami sandwich structure,and tried to use it in aerospace field.Due to its potential functions,continuous manufacturing technique,and abundant number of tunable parameters compared with honeycomb and foam core,Origami core has gained recognition from many scholars.In this paper,a new Origami folding pattern,namely Conical-Miura pattern,is designed and applied to truncated conical foldcore sandwich structures(TCFS).The mechanical properties of TCFS are studied from three aspects:analytical model,numerical simulation and experimental verification.Based on the principle of spatial geometry and Origami basic folding principle,Conical-Miura pattern is demonstrated to be flat-developable and flat-foldable,and its parametric design theory is proposed.By means of SOLIDWORKS and programming software,parametrized modeling,folding and unfolding process of truncated conical foldcore(TCF)and calculation of its equivalent analytical model are realized.Based on the hypothesis of rigid foldable Origami,an equivalent analytical model of TCF is established by combining bar and hinge model,so as to predict its axial stiffness.In contrast to the numerical simulation results,the feasibility of the equivalent analytical model of TCF is verified.The elastic mechanical behavior and failure modes of TCFS subjected to axial loads were investigated both numerically and theoretically.Considering the thin shell unit of the inner and outer face sheets,the analytical formula of local buckling failure is derived for TCFS.A parametric study on tunable parameters of TCFS and different lay-ups of face sheets was conducted.Based on the evaluation of ultimate load,failure mode and structural stiffness,the order of importance of different geometric parameters is given,and the influence on buckling mode and ultimate load of TCFS is summarized.Based on the hot-press molding technique,we designed the mould for TCF and conical face sheets,explored the fabrication method of TCFS,and manufactured several TCFSs with different parameters.By analyzing the load-displacement curve,the strain history and failure mode,the influences of face sheet thickness and boundary conditions on the ultimate load and failure mode of TCFS are summarized.There is a good agreement on the local buckling mode and fiber fracture position between the numerical and experimental results,which proved the validity of the FE method for the prediction of the axial compression behavior of TCFS.