Mechanical properties of additively manufactured metal lattice structures: Data review and design interface

Abstract

With the ever-increasing resolution of metal additive manufacturing processes, the ability to design and fabricate cellular or lattice structures is readily improving. While there are few limits to the variety of unit cell topologies that can feasibly be manufactured, there is little known about the effect that the underlying unit cell topology has on lattice structure mechanical performance. Increased knowledge of lattice structure performance based on the unit cell topology can aid in appropriate unit cell selection to achieve desired lattice structure mechanical properties. The objective in this work is to compile metal additively manufactured lattice structure characterization data found in the literature into Ashby-style plots that can be used to differentiate unit cell topologies and guide unit cell selection. Data gathered from literature encompasses over 69 papers describing 18 different unit cell topologies. Data on mechanical properties such as the effective modulus, Poisson’s ratio, yield strength, buckling strength, and plateau strength, of lattice structures from analytical models based on mathematical derivations, finite element analysis, and experimental characterization was gathered and synthesized. In total, nearly 1650 data points for experimental and finite element analysis were compiled along with a variety of analytical models for 18 different unit cell topologies. The process of gathering the data from the literature along with the assumptions used to compile the data are discussed. A graphical user interface and database were developed that allows for comparison of different lattice structure mechanical properties based on their unit cell topology. The Lattice Unit-cell Characterization Interface for Engineers (LUCIE) provides a simple format to guide engineers, scientists, and others towards understanding the relationships of the unit cell topology and the lattice structure mechanical properties, with the intent of guiding appropriate unit cell selection. Three cases studies are shown for using LUCIE to differentiate unit cell topologies for improved understanding of experimental and simulation-based results (Case Study 1), to identify unit cell topology options for reducing weight while maintaining yield stress or increasing yield stress without reducing weight (Case Study 2), and for quickly narrowing multiple options to an appropriate unit cell topology (Case Study 3).