A Preliminary Study on the Mechanical Performance of Tiled Polymer Composites

We are developing and exploring the concept of in-plane tiling of composite laminates, called MOSAIC, to mitigate or control delamination at free edges due to interlaminar stresses. Initial mechanical testing has shown that MOSAIC composites with uniaxial graphite-fiber reinforced tiles retain the stiffness levels of traditional uniaxially reinforced composites but with reduced strength. The reduction in strength is attributed to the formation of resin-rich pockets between adjacent tiles. In this study, we have performed detailed finite element analyses to identify the critical design parameters that affect the mechanical performance of uniaxially reinforced MOSAIC composites. We have found that using continuous laminae on the outer surfaces significantly increases the overall loadcarrying capacity. Increasing aspect ratio of the pocket and decreasing material property differences between resin and tiles also cause better load transfer between tiles but may not necessarily improve overall strength due to increasing stress concentration. The tiling scheme and density of pocket placement influence the interaction of local stress concentrations. Consequently, a novel composite joint is proposed and found to have superior performance.