Research on the Elastoplastic Properties of Auxetic Honeycombs under Tensile Load

The auxetic honeycomb core exhibits geometric nonlinearity under the in-plane load. As the load increases, the plastic deformation occurs. The elastoplastic model of the auxetic honeycombs with constant wall thickness is introduced based on nonlinear beam theory and elastoplastic theory. The solution algorithm is established. The elastoplastic properties of the auxetic honeycombs with different ratios of the thickness of honeycomb wall to the length of the inclined wall t/l, different ratios of the height of the vertical wall to the length of the inclined wall h/l, and different inclination angle θ are obtained. The results suggest that with the increase of strain, the geometric nonlinearity causes the overall stiffness of honeycombs to increase. Then it decreases gradually due to the plastic deformation.