Architectured and bioinspired materials to expand property space

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Ever-increasing requirements for structural performance drive the development of stronger, tougher and lighter materials. Despite rapid progress in materials science, there are still combinations of properties which are not available. For example toughness and strength remain mutually exclusive properties, and hard protection and compliance are difficult to combine. ***The proposed research aims at expanding material property space using two powerful concepts: architecture and bioinspiration. Architectured materials are high-information materials with controlled structures at length scales which are intermediate between microstructure and whole component. Of interest in the proposed research are dense architectured materials, made of building blocks of well-defined size and shape arranged in two or three dimensions. These building blocks are stiff, but their interfaces are softer and can channel large nonlinear deformations and cracks. These principles lead to building blocks which can slide, rotate, separate or interlock collectively, providing a wealth of tunable mechanisms, structural properties and functionalities. Another powerful concept central to the proposed research is bioinspiration. Bone, teeth or mollusc shells demonstrate how the interplay between stiff building block and non-linear interfaces generate unusual and highly attractive combinations of stiffness, strength and toughness. Other natural architectured materials such as scaled skins and fins demonstrate how hard and soft can be combined to make flexible exoskeletons with tendon-like effects or morphing capabilities. ***In the proposed program we will characterize the structure, properties and mechanics of hard biological materials and systems including teeth, bone, mollusk shells, arthropod cuticles, scales and fins. This activity will involve state-of-the-art experiments (small-scale and in-situ, digital image correlation, high speed imaging, stereo-imaging and 3D reconstruction). We will also develop theoretical and numerical models (finite elements, discrete elements) for these materials to capture key architectures and mechanisms. This activity will explore fundamental and critical questions related to separation of length scales and homogenization of properties in architectured materials. These models will be incorporated into design and optimization schemes for bioinspired architectured materials. Finally we will fabricate and test prototypes by combining bottom-up fabrication strategies (3D printing), with top-down approaches (two and three-dimensional laser engraving). ***The new bioinspired materials which will emerge from this program will have a variety of applications with high impact in the Canadian economy (biomedical, aerospace, automotive, energy), and the program will provide a vigorous training environment for highly qualified personnel at all levels.