Application of laminates to mouthguards: finite element analysis

A finite element model comprising a flat-ended indentor and a disc representing a colliding object and mouthguard materials, respectively, has been developed to study stress distribution and impact force in laminates. The disc consists of two layers and its top layer is in contact with the indentor. Two different combinations of layers were employed for the simulation. One had a soft layer placed on top of the rigid layer and the other was vice versa. It was found that the former had no significant difference from a monolayer in stress distribution and impact force. However, the latter was found to have a significant effect on stress distribution, and this effect could be increased by controlling ratios of modulus and volume fractions of the top and bottom layers. It was also found that the magnitude of the impact force increases with increasing effect of stress distribution, but this competition can be reduced to some degree by decreasing the volume fraction ratio of top to bottom layers.