Multifunctional design of prismatic cellular materials

Abstract

Low density, prismatic cellular materials have a combination of properties that make them suitable for multifunctional or multi-physics applications such as ultralight load-bearing combined with energy absorption and heat transfer. In this work, non-uniform, graded cellular materials are designed to achieve superior thermal and structural performance. A general multifunctional design approach is presented that integrates multiobjective decision-making with multi-physics analysis tools of structural and heat transfer performance. Approximate analysis models for heat transfer and elastic stiffness are utilized to analyze designs efficiently. Search/solution algorithms are used to solve multiobjective decisions by interfacing with customized and commercial software. During the design process, cell topology is assumed to be rectangular, but aspect ratios and dimensions of cells and cell walls are varied. Two design scenarios are considered – maximum convective heat transfer and in-plane elastic stiffness in the first case and maximum convective heat transfer and elastic buckling strength in the second case. A portfolio of heat exchanger designs is generated with both periodic and functionally graded cells. Both single- and multi-objective performance are considered, and trade-offs are assessed between thermal and structural performance. Generalization of this approach is discussed for broader materials design applications in which material structures and processing paths are designed to achieve targeted properties and performance characteristics within a larger overall systems design process, and process-structure-property-performance relations are manifested on a hierarchy of length and time scales.