Nacreous　composites　offer　significant　potential　for　applications　in　structural　damping　materials,　which　require　simultaneous　high　stiffness　and　damping　properties.　In　this　study,　we　propose　that　the　incorporation　of　functionally　graded　tablets　into　nacreous　composites　can　further　enhance　both　stiffness　and　damping　energy　dissipation　concurrently.　Analytical　formulae　for　the　loss　modulus,　storage　modulus,　and　loss　factor,　validated　through　a　series　of　finite　element　analyses,　were　derived　to　investigate　the　effects　of　variations　in　tablet　modulus,　structural　geometry,　and　constituent　properties.　Our　analyses　demonstrate　that　designing　a　parabolic　modulus　distribution　in　the　tablets　can　yield　optimal　strengthening　and　damping　results.　Furthermore,　the　characteristic　modulus　variation　degree,　overlap　length,　and　frequency　emerged　from　the　systematic　optimization　of　loss　and　storage　moduli.　Additionally,　numerical　experiments　and　model　predictions　demonstrate　that　the　loss　modulus　of　functionally　graded　nacreous　composites　surpasses　the　predetermined　design　limit　and　is　five　times　greater　than　that　of　existing　homogeneous　nacreous　composites.　Combining　the　developed　theoretical　model　presented　here　with　advanced　3D　printing　techniques　would　offer　effective　guidelines　for　designing　and　fabricating　high-performance　bio-inspired　structural　damping　composites.　©　2023　Elsevier　Ltd