Failure load prediction of steel-CFRP double strap joints under quasi-static tensile loading

Use of the carbon fiber reinforced polymer (CFRP) materials as externally bonded sheet is one of the cost savings approaches to repair and improve the strength of the damaged steel structures. In the present paper, a new strain based criterion, namely the critical normal strain (CNS) is presented. This criterion is utilized in order to estimate the load carrying capacity for a series of the steel-CFRP double strap joints with different bonding lengths. According to the CNS criterion, the composite joint fails when the normal strain along the adhesive mid-plane at a critical distance reaches to the critical value. Finally, the predicted values of the failure load obtained from the CNScriterion are compared with the experimental data reported in the open literature for failure prediction of composite adhesively bonded joints. It was found that the CNS criterion could provide good predictions to the experimental results of the failure load for all samples.

Keywords:

CFRP , Critical normal strain , Double strap joints , Failure load prediction