BIOMIMETIC POLYMER–CERAMIC COMPOSITES WITH HIERARCHICAL STRUCTURE FOR AEROSPACE TECHNOLOGIES

Abstract

This paper presents a review and comparative analysis of the expected physical and mechanical properties of biomimetic polymer–ceramic composite materials with hierarchical internal architecture, developed in analogy to natural structural materials such as bone and nacre, with the aim of evaluating their applicability as structural alternatives to conventional aerospace alloys and composites used in load-bearing airframe components. The study begins by identifying the limitations of traditionally employed materials – aluminum alloys (Al 2024-T3, 7075-T6) and carbon fiber-reinforced polymers – in terms of damage tolerance, fatigue durability, and post-critical behavior under complex stress states. Against this background, biomimetic design principles are examined as a strategy for achieving superior combinations of stiffness, fracture toughness, and energy dissipation capacity. Particular attention is given to the hierarchical organization of bone tissue – comprising a dense cortical shell and a porous internal architecture - as an engineering model for polymer–ceramic composite design. Based on a synthesis of available literature, the expected material composition of the proposed composite is formulated: an outer CFRP laminate shell functioning as a cortical analog, combined with a PEEK/PEKK polymer matrix reinforced with ceramic microspheres or porous Al₂O₃ filler. The scalability of mechanical properties through adjustment of matrix porosity and ceramic phase morphology is discussed in the context of theoretical models demonstrating flaw insensitivity at the nanoscale. A quantitative comparison of crack resistance coefficients for hierarchical and non-hierarchical composites of identical composition is presented, demonstrating that biomimetic architectural organization provides significantly higher crack resistance coefficient and fracture energy. The paper further presents finite element analysis of the stress–strain state in flat plates made from the proposed composite, aluminum alloy, and monolithic alumina under identical boundary conditions. The results confirm that the polymer–ceramic composite achieves a safety factor approximately five times greater than that of the aluminum alloy at more than 1.5 times lower density, while maintaining favorable specific strength characteristics relevant to airframe applications. The study concludes that biomimetic polymer–ceramic composites with hierarchical structure demonstrate considerable promise for aerospace structural applications, offering enhanced resistance to crack propagation, local buckling, delamination, and fatigue damage accumulation – failure modes critical to stringer, frame, and channel-section components of aircraft structures.