On the determination of the elastic constants of carbon fibres by nanoindentation tests

Nano-indentation instrumented tests are carried out at shallow depths on PAN-based and MPP-based carbon fibres. Indentation moduli obtained by performing the ten different measured orientations with respect to fibre axis. They used identify elastic constants of fibres, assuming a transversely isotropic behaviour, minimising cost function between estimated values. Inconstancies identified in-plane shear transverse reported literature values pointed out, some drawbacks nano-indentation method highlighted. An improved taking into account buckling mechanisms crystallites stake during indentation process, visible in hysteretic behaviour force-penetration nanoindentation curves, is proposed. It allows that accordance These properties fibres turn estimate epoxy matrix composites containing these Very good agreement found experimentally available unidirectional ply properties. excellent correlation experiments Finite Element Analyses response eventually found.