Experimental estimation and numerical validation of cohesive zone parameters in hydroxyl functionalized MWCNTs‐reinforced CFRP under pure mode II loading

Abstract

AbstractThe present study concerns the interface mode II fracture of hydroxyl functionalized multi‐walled carbon nanotubes (MWCNTs) reinforced carbon fiber epoxy composites. The well‐known cohesive zone model (CZM) is employed for investigating crack propagation. The major difficulty in applying the CZM is the parameter identification. In this work, the CZM's strength and energy parameters are determined reliably from the Short beam shear (SBS) and End‐notched flexure (ENF) tests, respectively, for pristine and three MWCNTs variations—0.1 wt.%, 0.2 wt.%, and 0.3 wt.%. The derived CZM parameters from the tests are imputed to a bilinear cohesive law to simulate the global load vs. displacement responses, which correlate well with the experimental findings. It is observed that the addition of 0.2 wt.% of MWCNTs increases the cohesive strength and fracture energy up to 14.14% and 17.78%, respectively, when compared to the pristine composites. Finally, the field emission scanning electron microscopy (FESEM) analysis is carried out to investigate the fracture mechanisms.Highlights Cohesive properties under mode II are estimated using standard fracture tests. The homogenization technique is used to calculate the effective properties of CFRP. The maximum % error among the experimental and the numerical peak load is 3.01%. A higher density of hackles with an increase of MWCNTs up to 0.2 wt.%.