Characterizing the Failure Envelope of a Conductive Adhesive

Abstract

This paper focuses on mechanical testing designed to determine the static failure envelope for a conductive adhesive. Samples were made by bonding copper pegs together with the conductive adhesive. The samples were then tested at various loading conditions including tension, tension shear, and compression shear. Results were analyzed in order to check for correlations between the data and the testing procedures. The statistical distribution of the data was also analyzed. Furthermore, a finite element model of the test sample was constructed and used to verify the assumptions made with respect to the interpretation of the data. The data from various loading conditions was then used to construct the static failure envelope of the material. A modified Coulomb–Mohr failure criterion was used to model the failure envelope of the conductive adhesive. This criterion contains four material constants to be determined experimentally. Once these parameters are determined, a failure envelope can be easily constructed. The envelope can then be used to predict failure at any combination of shear and normal stresses. The test results showed that the empirical data are well characterized by the modified Coulomb–Mohr failure envelope.