Experimental testing and micromechanical modelling of unidirectional CFRP composite laminae under multiaxial loading conditions

This paper presents comprehensive experimental testing and numerical modelling of the failure behaviours of unidirectional carbon fibre reinforced polymer (UD-CFRP) composite laminae under multiaxial loading conditions. A novel modified Arcan test rig with a rotational clamp was developed to enable multiple stress combinations with out-of-plane stresses in UD laminae on a traditional laboratory-based uniaxial test machine. The test rig was verified by uniaxial tension and validated by off-axis tension. UD CFRP laminae were tested for the first time under five stress combinations using the test rig, with results cross-validated against a high-fidelity representative volume element (RVE)-based 3D micromechanical finite element model. Failure strength envelope and damage mechanisms demonstrate the applicability of the test rig for composite failure under multiaxial loading conditions with a broad spectrum of stress combinations.