Crack growth analysis of a composite/adhesive interface toughened by in-mold surface preparation

The present study performs in-mold surface preparation by imprinting microstructures to achieve high toughness of adhesive bonding during the curing of composites. Since the microstructures are fabricated on composites during curing, this technique saves the time required for and costs involved in conventional surface preparations such as sand blasting and chemical etching. To predict the effect of the microstructures on the composite/adhesive interface toughness, crack growth analysis of the interface with microstructures was performed using the finite element method and a cohesive zone model. The effects of the microstructure size and shape were investigated. It was found that the toughness is characterized by the microstructure shape, whereas the effect of the microstructure size is insignificant. From these results, a simplified formula was constructed to predict the toughness.