Application of fracture mechanics to predict the failure load of adhesive joints used to bond CFRP laminates to steel members

The use of bolted or welded elements to upgrade metallic structures has been a common practice for many years. Moreover, the use of adhesively bonded carbon fiber reinforced polymer (CFRP) laminates, as an alternative method, has attracted a great deal of attention in recent years. One important aspect of the design of adhesive joints used to bond CFRP laminates to steel substrates is the determination of the properties of the CFRP/adhesive/steel interfaces, which have not yet been established in codes or standards. The purpose of this paper is experimentally to determine the fracture properties of the adhesive material and to evaluate the accuracy of numerical methods using this information, in order to predict the strength of adhesive joints in steel members bonded with CFRP laminates. The results from four series of experimental tests are compared with numerical results and discussed in terms of load-bearing capacity and failure modes.

► Traction separation laws for thick adhesive experimentally determined.
► ABAQUS cohesive elements successfully used to model experiments in Modes I and II.
► Tensile and bending loaded specimens experimentally tested and numerically modeled.
► Failure loads overestimated due to failure mode switch from cohesive to adhesive failure.
► Suggestions are given to develop a method to overcome this issue.