A design of composite spar/shear web with ZPR honeycombs and graded structures for wind turbine blades.

It is of great essence to unveil relationship between structure, mechanical properties, and application of bionic design. Targeting at alleviating the debonding failure issue in the internal structures of the wind turbine blade, the reversed-semi-reentrant (RSRE) honeycomb and the angular gradient (AG) honeycomb with zero Poisson's ratio are considered in the design of the spar/shear web structure. Through finite element methods, the mechanical behaviors of these two types of honeycombs were compared to that of the hexagonal honeycomb. The ability of the RSRE honeycomb to reduce the shear stress on the skin–core interface is proved. The AG honeycomb also proves to have advantages in improving the shear stress distribution inside the honeycomb. Then, the RSRE honeycomb and the AG honeycomb are assembled together to build a complete model of spar/shear web structure. The results of simulations of the whole model under different loading conditions show that these two honeycombs have effectively promoted the mechanical behaviors of the whole model. [ABSTRACT FROM AUTHOR]