Geometry-Dependent Transverse Shear Stiffness of Corrugated Board

This study examines how flute shape and geometric proportions govern the effective transverse shear stiffness of corrugated-board cores. Six profiles are compared at common nominal dimensions and material properties using a strain-energy estimate, the Timoshenko frame model for shear in the corrugation plane, and a membrane-path model for shear along the flute axis. Finite element solutions and mesh refinement provide numerical verification. For the reference configuration, the predicted core shear moduli span 1.52-106.36 MPa in the corrugation plane and 38.20-60.00 MPa along the flute axis. The directional rankings reflect different contributions from axial deformation, bending, and shear along the free flute path. The triangular profile combines the highest frame shear modulus with the lowest material consumption, whereas the rectangular profile gives the highest membrane shear modulus under full plateau bonding. Parametric analyses show that flute height, pitch, and wall thickness affect the two directions differently, with distinct trends for shear modulus and rigidity. The framework provides a reproducible basis for comparing flute geometries within small-strain linear elasticity under rigid face constraints and ideal bonding; predictive accuracy for manufactured board requires experimental validation.