Resin matrix composites are widely utilized in a variety of typical load-bearing and non-load-bearing constructions in fields such as aeronautics and aerospace. With structural and functional integration

traditional off-line monitoring approaches can no longer match composites’ sophisticated expectations. With the ongoing development of structural health monitoring (SHM) of composite materials

flexible sensors primarily composed of conductive particles such as carbon nanotubes

graphene

and MXene have opened up new possibilities for early damage detection

early warning of service status

and intelligent diagnosis of composite materials. This paper primarily undertakes a systematic evaluation of the structural health monitoring technology of flexible sensors

focusing on introducing the design ideas

essential technologies

mechanism mechanisms

and application advancements of flexible sensors

and looking ahead to their future applications.