Material Properties and Mold Folded Core Based on Ultra-violet Cured Resins

Ultra-violet(UV)curing is an efficient method for composite molding.Firstly,thermophysical properties of UV cured glass-fiber reinforced plastics are conducted.Material properties are studied for various kinds of postcuring modes.Then the UV curing method is suggested in manufacturing V-crimp folded core for sandwich panels.Two kinds of processing schemes for V-crimp folded core manufacturing using UV curing are presented.Finally,the effect of post-curing on the mechanical properties of folded core sandwiches is experimentally studied,and optimum modes of post-curing are determined.The experimental results show that the ultimate compressive strength of the folded sandwiches is increased by 60% after post-curing with the optimum post-curing mode.

The Compressive and Shear Characteristics of Miura-ori Forms as Core Materials of Sandwich Structures

The mechanical properties of Miura-ori foldcore metamaterials were studied using finite element simulations.The responses of foldcores with various topological parameters to quasi-static out-of-plane compression and shear loading were analyzed using the relative density as a governing parameter.The non-unique relationships between the core density and the materials'strength in the examined loading directions were revealed,pointing out the strong influence of the Miura-ori topology.Linear relationships were established between the elastic moduli and relative densities of the Miura-ori metamaterials while power-law functions of the relative density with different exponent constants were established for the strength in different loading directions.It was shown that the Miura-ori materials possess the highest strength under shear in the X1-X3 plane and it increases with the increase in the relative density.However,this characteristic is strongly influenced by the sector angleα.In general,the difference between the two shear strengths increases when increasing the relative density by using thicker cell walls.It is noted that the strength of the Miura-ori materials as a function of the relative density is nearly constant with respect to the cell dimensions if the values of folding angleγ0 and sector angleαare given.The mechanical characteristics of the Miura-ori material with equal relative density,which exhibits the highest strength among the analyzed origami models,are compared with the out-of-plane compression and shear responses of prismatic hexagonal honeycomb.It is observed that compression and shear responses of the honeycomb outperform the Miura-ori foldcore in all loading directions when considering large deformations.