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 t est. 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 b oard at the supports and contribution from bending deformation of the facings in the three-point bend test. Experimental results were compar ed to shear moduli obtained by finite-element analysis (FEA) and analy tical predictions. Shear modulus along the corrugations, determined wi th the three-point bend test, was about half of the predicted value us ing FEA, while the shear modulus transverse to the corrugations was su bstantially below that prediction from FEA, apparently due to delamina tion damage of the core material inflicted during the corrugation proc ess. (C) 1997 Elsevier Science Ltd.