Application of a new experimental method to determine bi-material interface bonding strength

Abstract

The accurate measurement of interface bonding strength is important in order to predict the failure or damage behavior of structures and materials containing bi-material interfaces. Due to the discontinuity of material properties, stress singularity may exist at the edges/corners of bi-material interfaces, which causes difficulty in accurate evaluation of interface bonding strength. In many practical applications, interface failures occur under the actions of combined normal and shear stresses. Therefore, a biaxial normal-shear bonding strength envelope is preferred. This paper presents a general experimental method for the determination of interface bonding strength envelopes for different combinations of material types. Finite element analyses are first carried out to determine the appropriate interface design parameters to eliminate the stress singularity. Then, tests are carried out with the designed specimens under pure tensile, pure torsional, and various combined tensile-torsional loadings to obtain the interface failure loads of each loading case. The final interface bonding strength envelope, which is expressed by a quadratic expression, is determined by an iterative calculation technique integrated with the finite element analysis. By using the proposed method, the interface bonding strength envelope of a Polyvinylchloride (PVC)/Epoxy (viscoelastic/viscoelastic) interface is determined. © The Society for Experimental Mechanics, Inc. 2013.