On Approximately Realizing and Characterizing Pure Mode-I Interface Fracture Between Bonded Dissimilar Materials

摘要

Bimaterial systems in which two dissimilar materials are adhesively joined by a thinnadhesive interlayer have been widely used in a variety of modern industries and engi-nneering structures. It is well known that interfacial fracture is the most common failurenmode for these bimaterial systems. Particularly, the interface fracture is a mixed mode innnature mode-I (pure peel) and mode-II (pure shear) due to the disrupted symmetry by thenbimaterial configuration. Obviously, characterizing individual fracture modes, especiallynmode-I fracture, is essential in understanding and modeling the complex mixed modenfracture problems. Meanwhile, the J-integral is a highly preferred means to characterizenthe interfacial fracture behaviors of a bimaterial system because it cannot only capturenmore accurate toughness value, but also facilitate an experimental characterization ofninterfacial traction-separation laws (cohesive laws). Motivated by these important issues,na novel idea is proposed in the present work to realize and characterize the pure mode-Innonlinear interface fracture between bonded dissimilar materials. First, a nearly purenmode-I fracture test can be simply realized for a wide range of bimaterial systems bynalmost eliminating the mode-II component based on a special and simple configurationnobtained in this work. Then, the concise forms of the J-integral are derived and used toncharacterize the interfacial fracture behaviors associated with classical and shear defor-nmation beam theories. The proposed approach may be considered as a promising candi-ndate for the future standard mode-I test method of bimaterial systems due to its obviousnaccuracy, simplicity, and applicability, as demonstrated by the numerical and experimen-ntal results. u0001DOI: 10.1115/1.4003366