Elastic buckling of hexagonal honeycombs with dual imperfections

The theoretical expression for describing the elastic buckling strengths of hexagonal honeycombs with dual imperfections of non-straight and variable-thickness cell edges was derived from a model of curved cell edges with Plateau borders. Finite element analyses on the elastic buckling strengths of hexagonal honeycombs with dual imperfections were also performed and then compared to the theoretical modeling; they agree well except when either the solid distribution in cell edges is highly non-uniform or the curvature of cell edges becomes much larger. Both theoretical and numerical results indicate that the effects of dual imperfections are more significant as compared to those of each single imperfection. Moreover, the normalized elastic buckling strength of a hexagonal honeycomb with dual imperfections is found to be approximately equal to the product of that with each single imperfection. In other words, the elastic buckling strength of a hexagonal honeycomb with dual imperfections can be directly estimated from that with single imperfections.