Functionally graded engineering structures: An overview

Abstract

Functionally graded materials (FGMs) are engineered composites inspired by natural materials, which have been extensively investigated over the last decade as a design concept for improving the mechanical and multifunctional performances of engineering structures. By distributing material composition, density/porosity, filler content, or geometric parameters into gradient patterns, FGMs can significantly outperform traditional composites and achieve significantly enhanced mechanical, thermal, and functional properties. This review summarizes recent progress in the development of FGMs in engineering structures involving four major categories, including functionally graded concrete structures, porous structures, nanocomposite structures, and metamaterials. The effective material property models, gradient strategies, and typical structural forms are systematically discussed in these categories. The review demonstrates the advantages of FGMs in improving strength, stability, vibration performance, toughness, thermal resistance, and durability. Challenges in fabrication scalability, numerical modelling, standardization, sustainability, technological integration, and commercial adoption are identified, and future opportunities, including the integration of additive manufacturing, multiscale computational approaches, artificial intelligence-assisted design, and the adoption of sustainable raw materials, are discussed. The article concludes that FGMs provide a versatile and promising platform for the design of advanced structural systems. Further interdisciplinary research will be critical to enable their practical applications in civil, aerospace, mechanical, and energy engineering. • Gradient strategies adopted in different FGESs are summarized and classified. • A comprehensive review of typical structural forms of FGESs is presented. • Key challenges and future opportunities for multifunctional FGESs are discussed.

Topics & Concepts