Toughening of dissimilar interfaces with patterned morphology
Fernando Cordisco (Purdue), Pablo Zavattieri (Purdue), Louis J. Hector, Jr. (General Motors R&D), Allan Bower (Brown University)
Materials Design and Biomimetic Material Concepts
Tue 9:00 - 10:30
CIT 227
Interfaces often contribute to a wide range of properties that are of scientific and technological importance. In many cases it has been observed that micropatterning at interfaces contributes to the bulk mechanical properties of heterogeneous materials. Grain boundaries in metal alloys or dislocation patterns in metals represent a few examples in man-made materials. In Nature, patterned interfaces are often found in organic-inorganic interfaces of biomineralized materials ranging from shells to bones. Patterned crack propagation around bone osteons has been suggested as one of the mechanism to improve fracture toughness, bone-ligament junctions are designed to improve adhesion between different material phases, and in Nacre, non-planar wavy interfaces observed at the micron scale have been related to the material toughening. As new processing techniques that can accurately control periodic patterns at the macro, micro and nano scales become available, it becomes increasingly important to achieve a quantitative understanding of how patterns influence interface mechanics for the development of new processing techniques and products. A computational model is used to study the behavior of a crack that propagates along a sinusoidal cohesive interface between two dissimilar elastic plastic solids subjected to mode-I loading conditions. The model is able to capture the transition between brittle and ductile crack propagation in terms of the material system selected. In addition, we find a strong relation between the pattern aspect ratio and the stable/unstable crack propagation regimes which can be used to significantly improve the toughness in patterned material systems.