Prediction of pull-out force of multi-walled carbon nanotube (MWCNT) in sword-in-sheath mode

► We proposed an empirical theory to predict pull-out force of MWCNTs in the sword-in-sheath fracture mode. ► We highlighted that the contribution of cap of MWCNTs to the pull-out force. ► We carried out the pull-out experiments of MWCNTs to verify the present theory.