APPLICATION OF LAMINATES TO MOUTHGUARDS - FINITE-ELEMENT ANALYSIS

A finite element model comprising a flat-ended indentor and a disc rep resenting a colliding object and mouthguard materials, respectively, h as been developed to study stress distribution and impact force in lam inates. The disc consists of two layers and its top layer is in contac t with the indentor. Two different combinations of layers were employe d 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 n o significant difference from a monolayer in stress distribution and i mpact force. However, the latter was found to have a significant effec t on stress distribution, and this effect could be increased by contro lling ratios of modulus and volume fractions of the top and bottom lay ers. It was also found that the magnitude of the impact force increase s 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.