FRACTURE OF SURFACE NOTCHED CERAMIC/CONDUCTIVE EPOXY/GLASS SPECIMENS SUBJECTED TO THERMO-MECHANICAL LOADING

摘要

The primary objective of this combined experimental and analytical study was to investigate the mechanical behavior of glass/conductive adhesive/Al{sub}2O{sub}3 systems with a surface notch, measure the properties of the system at various temperatures, implement these temperature dependent properties into a nonlinear finite element framework, and predict the initiation and growth of cracking. The three major tasks of this work include (a) testing of fracture strength of the systems at three different extreme temperatures, including the determination of thermal crack initiation and growth, (b) determination of basic thermal-mechanical properties of adhesive, glass, and Al{sub}2O{sub}3, respectively, and (c) application of J integral to predict damage modes, including initiation and growth, at different temperatures and comparing the data with experiments. The major conclusions are as follows: (a) realistic nonlinear material properties are essential input for correct nonlinear finite element modeling, (b) J integral can be applied to predict the crack initiation and growth for the material system considered, (c) either bulk glass material or the adhesive/glass interface may fail depending on the applied temperature and notch length, and (d) curved crack growth path inside the glass can be predicted by fracture mechanics.