Degradation mechanisms and mechanical behavior of composite-metal bolted/riveted joints in complex service conditions: a comprehensive review

Composite-metal bolted/riveted joints are critical in lightweight, high-performance engineering systems (e.g., aerospace, automotive, marine), where they endure complex service conditions-simultaneous exposure to environmental factors and mechanical loading. This review synthesizes degradation mechanisms and mechanical behaviors of these joints under such service conditions. Key findings reveal that composite degradation (matrix softening, plasticization, cracking and delamination) and metal corrosion (plate and fastener) synergistically reduce the mechanical performance of the joints, while structural loosening and interfacial wear exacerbates joint instability. Mechanical loading intensifies these issues by amplifying environmentally induced material damage and exacerbating wear at the overlap interface. Concurrently, the failure mechanisms of the joints shift from design-predictable, progressive failure to unpredictable, catastrophic brittle failure, posing severe risks to structural integrity during service. In addition, proven mitigation strategies-including interference-fit optimization, hybrid fastener integration, and corrosion-resistant coatings-have validated their efficacy in enhancing joint durability. This synthesis establishes a foundational framework for designing lightweight, resilient hybrid joints capable of withstanding multifaceted service demands. Future efforts should prioritize coupled multi-scale simulations, data-driven prediction, and adaptive protection technologies to ensure structural integrity and extend service life in demanding applications.