Interfacial Design and Mechanics Analysis of Advanced Materials and Structures

Abstract

Many natural and technological processes involve phenomena dominated by interfacial mechanics – occurring within the overlapping region between several solid/fluid phases. Interfacial phenomena typically involve interplay of complex processes and the exact mechanics involving such processes is still not fully understood. As advanced materials and structures are being investigated to better optimize weight, cost and strength, it is imperative that material interfaces be better characterized in terms of their properties, thereby increasing reliability in usage.

Reliability can be increased either by building better structures or by manufacturing better materials. In this light, a method has been investigated to remove stress singularity at bi-material corners and thereafter applied to explain the reduction in the tensile strength of bonded interfaces after the incorporation of graphitic carbon nanofibers in the epoxy matrix. This approach is expected to produce more reliable material strength data. Simultaneously, in the context of a different bi-material problem (thin film-substrate), the fracture mechanics approach was utilized to propose a novel method for measurement of interfacial fracture toughness. In the final part of the study, the influence of non-uniform stress distributions at material interfaces was investigated to understand interfacial failure in brittle materials.