Optimized internal geometries for lightweighting and multifunctionality in additive manufacturing – an ideal processing target

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One of the great opportunities in additive manufacturing is the ability to manufacture complex optimized internal geometries such as lattices and honeycombs for space filling applications. Some obvious applications including sandwich panels for lightweighting and multifunctionality, energy-absorbing structures, buoyant materials, heat exchangers, implantable medical devices, and building materials, to name but a few. Highly tailored and optimized materials will allow access to new design space and capabilities. In the context of additive, an optimized design would use a minimum amount of material to achieve design requirements, minimize the energy required to complete a build, and minimize the build time. To this end, we have identified the first and only material geometry that achieves theoretical bounds for strain energy storage and linear elastic structural efficiency. This design has the advantageous attributes of being composed of sheets of material, providing a relatively simple geometry that can be formed form sheet stock, not just by additive processes. The design maintains essentially maximum structural efficiency over the entire range of relative densities that are practical for cellular materials, 0 to 40+%. The design is composed of two unique and highly anisotropic but maximally efficient subgeometries, whose relative contribution can be modified through the wall thicknesses to create functionally graded designs, with locally varying stiffness, strength, anisotropy, conductivity, and other properties that relate to the geometry. Initial experiments of additively manufactured unit-cell test specimens composed of FDM ABS plastic and EBM titanium agree well with numerical and analytical predictions for stiffness. In this talk, we will discuss potential routes to fabrication, processing challenges, potential applications, and opportunities for highly optimized designs. Through the NSF I-corps program, potential applications, ranging from aerospace to biomedical devices have been explored, and some of the more promising applications will be discussed, as well as some of the barriers to the adoption of additive and this type of technology.

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Journal: TechConnect Briefs
Volume: 4, Informatics, Electronics and Microsystems: TechConnect Briefs 2018
Published: May 13, 2018
Pages: 100 - 103
Industry sector: Advanced Materials & Manufacturing
Topics: 3D Printing
ISBN: 978-0-9988782-1-8