Size effect in penetration fracture of sea ice plate: Review of theory and experimental evidence

Vertical load capacity of a floating sea ice plate is analyzed by fracture mechanics. The radial bending cracks, which are considered to reach only through apart of the plate thickness and have a variable depth profile, are assumed to follow the Rice-Levy nonlinear softening Line spring model. The plate-crack interaction is characterized in terms of the compliance functions for the plate wedge between radial cracks. Numerical calculations show a typical quasibrittle size effect such that the plot of log sigma(N) vs. log h (sigma(N) = nominal stress at maximum load, h = plate thickness) is a descending curve whose slope is negligible only for h < 0.2 m and then gets gradually steeper, asymptotically approaching -1/2. The calculated size effect agrees with the existing test data, and contradicts Sodhi's plasticity solution.