Evaluation of transverse shear stiffness of structural core sandwich plates

Effective transverse shear moduli in the principal material directions of corrugated board were examined experimentally for five corrugated board types using the ASTM block shear test and the three-point bend test. It was found that shear moduli determined by the three-point bend test are significantly lower than those obtained from the block shear test. The difference is probably caused by local indentation of the board at the supports and contribution from bending deformation of the facings in the three-point bend test. Experimental results were compared to shear moduli obtained by finite-element analysis (FEA)and analytical predictions. Shear modulus along the corrugations, determined with the three-point bend test, was about half of the predicted value using FEA, while the shear modulus transverse to the corrugations was substantially below that orediction from FEA, aooarentlv due to delamination damage of the core material inflicted du g the- corrugation process.