Estimation of the local interfacial strength parameters of carbon nanotube fibers in an epoxy matrix from a microbond test data

Local interfacial strength parameters (local interfacial shear strength (IFSS), critical energy release rate) and interfacial frictional stress between continuous carbon nanotube fibers and epoxy matrix have been estimated using published experimental data from a microbond test. The ‘indirect’ method (from the maximum recorded force as a function of the embedded length) and the calculation from an individual force–displacement curve yielded very similar results. The estimated local IFSS value (about 50 MPa) is much greater than the effective IFSS reported for this fiber–matrix pair (14.4 MPa).