Design and mechanical analysis of a reverse semi-re-entrant honeycomb structure with zero Poisson's ratio

A novel zero Poisson's ratio (ZPR) reverse semi-re-entrant (RSRE) honeycomb structure was designed for the deformation and load-bearing requirements of the flexible skins of the morphing wing. A theoretical model for the elastic constants of the RSRE structure was established based on Castigliano’s second theorem, which shows that the equivalent modulus of elasticity of the structure is 2-4 orders of magnitude lower than that of the base material, and its maximum global strain can be up to 6-7 times that of the base material. The influence of the geometrical parameters of the cell element on the in-plane deformation capacity of the structure was deeply discussed, and the results show that the width of the cell wall has the greatest influence on the deformation capacity of the structure, followed by the inner angle of the cell element. Compared with the existing star zero Poisson 's ratio honeycomb structure, the RSRE structure proposed in this paper has a lower elastic modulus and stronger deformation ability. The reliability of the theoretical model and finite element simulation results was verified by experiments. In terms of structure preparation, a preparation method combining molding and winding processes was proposed for carbon-fiber-reinforced polymer reverse semi-re-entrant (CFRP+RSRE) honeycomb structures. Compared with the cutting method of laminated panels, the in-plane load-carrying capacity of the specimens prepared by this process increased by about 290%, and the failure displacement is improved by 160%.