Fracture tests on structural adhesive joints

Abstract

Publisher Summary This chapter focuses on fracture tests on structural adhesive joints. The protocol is based upon a linear-elastic fracture-mechanics (LEFM) approach and is designed to be used to determine the value of the adhesive fracture energy, of structural adhesives under Mode I loading. The specimens in the protocol are bonded joints based upon double-cantilever beam (DCB) and the tapered double-cantilever beam (TDCB) specimens. The DCB specimen of the protocol is well-suited for testing joints consisting of an adhesive which is bonding relatively thin sheets of fiber-composite materials, but may also be used when metallic substrates which possess a relatively high yield stress are being employed. The adhesively-bonded steel joints were tested in both the DCB and TDCB test geometry. It is observed that the glass transition temperature of the particular rubber-toughened adhesive is very much dependent upon the exact heating cycle used to cure the adhesive, and the amount of water present in the CFRP substrates prior to forming the joint.