Keywords

additive manufacturing, stiffness, elasticity, Nylon 12, Finite Element Analysis, materials

Abstract

Typically additive manufacturing (AM) processes are limited to a single material per part while many products benefit from the integration of multiple materials with varied properties. To achieve the benefits of multiple materials, the geometric freedom of AM could be used to build internal structures that emulate a range of different material properties such as stiffness, Poisson’s ratio, and elastic limit using only one build material. This paper examines the range of properties that can be simulated using diamond lattice structures manufactured from Nylon 12 with a commercial laser sintering process. Diamond lattices were fabricated with a unit cell length ranging from 5 – 20 [mm] and strut thickness variation of 0.5 – 2 [mm]. Stiffness and energy absorption were measured for all parts and compared to finite element analysis (FEA). Simulation shows agreement with experimental results over a stiffness range of four orders of magnitude once a correction factor is applied. The correction factor implements a constant offset in strut thickness from the design geometry. Experimental results also shows a wide range of energy absorption for diamond lattice structures and a significant increase in the effective elastic limit of the material-compensating for the low ductility of many AM materials. Extrapolating this data into lattice structures made from metal, these same structures could mimic a wide range of “fully” dense and porous materials with just the use of a single material. Since the diamond lattice is a cellular structure, the voids can also be filled with other materials/structures to add secondary control of functions such as energy storage, and sensing.

Original Publication Citation

Clayton Neff, Neil Hopkinson, and N. B. Crane, “Experimental and theoretical investigation of mechanical response of laser-sintered diamond lattice structures,” Additive Manufacturing, V 22, p 807-816, August 2018.

Document Type

Peer-Reviewed Article

Publication Date

2018-8

Publisher

Additive Manufacturing

Language

English

College

Ira A. Fulton College of Engineering and Technology

Department

Mechanical Engineering

University Standing at Time of Publication

Full Professor

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