Glass reinforced epoxy tubes subjected to indentation load: A study of scaling effects

Scaling effects in thin walled glass reinforced epoxy filament wound cylindrical tubes with [±55°] layup subjected to indentation load are presented in this work. Buckingham PI theorem is used to scale input and output parameters for four different scales (n=1/4, 1/2, 3/4 and 1). Scaling laws are investigated for force, energy dissipation and damage propagation when tubes are resting on a flat surface. Damage propagation is captured with a video camera, by recording damage reflection on an upward facing mirror placed inside the tubes. The threshold force causing onset of delamination is identified and used for calculation of mode II energy release rate G_IIC with already established relation between the two. The scaling laws have been found effective in estimating quite a few parameters, including force displacement, energy displacement relation and peak load. Damage growth is found to obey scaling law and it is presented with respect to force applied, energy dissipated, indentation displacement and time.