Equivalent in-plane elastic modulus of honeycomb sandwich in the direction of cell vertical wall

The equivalent in-plane elastic modulus (Formula presented.) of a honeycomb sandwich in the direction of cell vertical wall can be assessed by the law of mixture from the modulus of face sheet (Formula presented.) and the equivalent modulus of honeycomb core (Formula presented.). However, significant errors as large as 40% can be made depending on material and geometry parameters, when the used (Formula presented.) is obtained from a cellular model of core alone without considering the skin effect of face sheet. The main reason of the error is that the rigidity to deformation of y-direction is different greatly between the vertical cell wall of core and inclined cell wall of core. In the present paper, an analytical model is proposed to assess (Formula presented.) of honeycomb sandwich with considering the interference effect of the core with the face sheet. In the proposed model, the influence of the face sheet rigidity on (Formula presented.) is taken into account. The results demonstrate that the contribution of the core to (Formula presented.) is also dependent on the face sheet rigidity significantly. The validity of presented model is verified by comparing the results with numerical results of FEA.