Dynamic response of multi scale periodic materials and structures

点击翻译按钮获取中文摘要

Modern structural materials are designed to achieve high stiffness, strength, toughness and damping with minimum weight to build efficient structural components used in manufacturing (moving machine tool structures) and transportation (sandwich panels in naval, aerospace and automotive industries). Combining two or more materials fulfils the conflicting material property requirements by creating a new hybrid material with properties superior to those of its parent materials. Composite materials using particles or fibres in a background matrix medium are illustrative of hybridization at the material level. Engineering application of these lightweight materials can be further enhanced, at the structural level, by extending the same idea of hybridization, embodied in sandwich construction using a core material bonded between two face sheet materials. The above two engineering practices lead to the question: can one design hybrid materials by borrowing examples from structural construction utilizing size, scale, and shape? The quest to answer this question has first lead to the development of metal and polymeric foams and more recently lattice materials. These new class of periodic materials are being developed to fulfil not only the structural efficiency requirements of high specific stiffness and strength, but also other functional requirements such as favourable thermal and vibro-acoustic response. Recent developments in manufacturing technologies such as rapid prototyping, 3-D printing, soft lithography have invigorated research to design multifunctional structural materials. Given the lack of stiffness of foams due to their random micro-architecture, attention has now turned onto materials with periodic microstructure. Emerging manufacturing techniques not only offer the ability to combine two materials but also control the shape (micro-architecture) and length scale leading to the creation of innovative materials, structures, and devices.**The ability to control wave and acoustic response by designing periodic microarchitecture has led to the emergence a new class of periodic composite materials with promising vibroacoustic and dynamic response characteristics. Whereas periodicity is engineered in mesoscale periodic materials, periodicity is intrinsic to nanomaterials such as Single Layer Graphene (SLG) and Carbon Nanotubes (CNT), wherein carbon atoms are arranged in a hexagonal lattice. At both scales the presence of defects and sources of nonlienarity are unavoidable. While interatomic potentials are the sources of nonlinearity in SLGs and CNTs, geometric and material nonlinearities are relevant to micro truss lattice materials. The proposed research will study linear and nonlinear dynamic response of micro and nanoscale periodic materials particularly in the presence of defects and dissipation mechanisms. **The proposed research is concerned with dynamic response of multiscale periodic materials and structures. The long-term goal of this research, combining theory and experiments, is to understand the influence of microstructural scale, shape, and size on effective mechanical properties, vibro-acoustic, and wave propagation response of periodic materials. The research will focus on periodic materials at mesoscale in the short-term. Fundamental knowledge generated will be exploited to design multifunctional structures and devices for applications in manufacturing, aerospace, and biomedical industries. Such wide-ranging applications are possible due to the basic building-blocks approach pursued. This research program will train four graduate students (2 PhDs and 2 MAScs) over the next five years in this emerging area of interest to global research community and Canadian aerospace and manufacturing industries.