Additive Manufacturing and Cellular/Lattice Structures: Designs, Realization and Applications: Cellular/Lattice Structures I
Sponsored by: TMS Additive Manufacturing Committee, TMS Materials Characterization Committee
Program Organizers: Li Yang, University of Louisville; Allison Beese, Pennsylvania State University; John Carpenter, Los Alamos National Laboratory; Carolyn Seepersad, Georgia Tech; Miguel Aguilo, Morphorm LLC
Monday 8:00 AM
October 10, 2022
Room: 305
Location: David L. Lawrence Convention Center
Session Chair: Li Yang, University of Louisville
8:00 AM
Design, Manufacture, Modelling and Testing of Honeycombs with Aperiodic Order: Richard Moat1; Chikwesiri Imediegwu1; Daniel Clarke1; Patrick Carter1; Iestyn Jowers1; Uwe Grimm1; 1The Open University
Cellular structures are commonplace in engineering applications. Typically, cellular structures are based on patterns of periodically repeating unit cells, however the periodic nature and available symmetries of the patterns can give rise to anisotropic performance. Patterns with aperiodic order are a viable alternative that can limit anisotropy. Aperiodic patterns have rotational symmetry, yet no translational repetition and can be designed with higher orders of symmetry thereby potentially reducing the mechanical anisotropy. In this study, 2.5D honeycombs based on aperiodic tilings have been designed and manufactured using additive manufacturing. The mechanical properties and mechanical anisotropy have been characterised using a combination of modelling and mechanical testing. The outcome is a wide variation in elastic moduli, volume constant and plastic behaviour exhibited across a range of aperiodic patterns and all with relatively low levels of anisotropy
8:20 AM Cancelled
A Simplistic Experimental Study of the Material Property and Quality Issues with Topology Optimization Designs Fabricated by Powder Bed Fusion Additive Manufacturing: Li Yang1; William Dorsch1; 1University of Louisville
Additive manufacturing (AM) has been regarded as arguably the optimal technology for the realization of topology optimization designs. However, there still exist challenges with such design approach, such as the geometry design limitations imposed by manufacturability and the inaccuracy of design prediction due to material imperfection. This work aims to provide an experimental demonstration of the potential inaccuracies of topology optimization designs due to material imperfection-type issues. Multiple generic benchmark designs such as bracket and corner joint were designed using topology optimization. The resulting designs were further segmented into simplistic geometries such as thin walls and thin beams, which served as material benchmark coupons and were subsequently fabricated with identical setting as the topology optimization designs. Experimental testing with the material benchmark coupons were carried out, and the resulting material quality information were used to quantify the contribution of material imperfection to the predictability of topology optimization methods.
8:40 AM
3D Printed Fibrous Cellular Multifunctional Structures: William Johnston1; Janith Godakawela1; Carlos Gatti1; Suresh Keshavanarayana1; Bhisham Sharma1; 1Wichita State University
Engineering designs frequently result in antithetical performance requirements. For instance, while foams with smaller pore sizes can provide better noise reduction performance, their use in applications such as computer fan noise reduction is typically infeasible because of airflow requirements to ensure heat dissipation. Here, we introduce the idea of utilizing fibrous structures as a solution to meet such contrasting design requirements. Using our recently demonstrated method of printing fibrous geometries using extrusion-based printing methods, we add an internal fibrous mesh to an open-cellular, load-bearing scaffolding structure. The addition of the fibrous mesh drastically increases the acoustic absorption, while minimally increasing the flow resistance. We also study the effect of the fiber mesh on the energy absorption capabilities of the scaffolding structure. Our work shows that the addition of a fibrous mesh can help improve functional and mechanical properties with minimal weight and flow penalties.
9:10 AM
AM-Fabricated Plate Lattice Structures for Impact Applications: Joseph Berthel1; Nicholas Jones1; Brandon McWilliams2; Jian Yu2; Rahul Panat1; Jack Beuth1; 1Carnegie Mellon University; 2US Army DEVCOM Army Research Laboratory
Additive manufacturing has the capabilities to fabricate complex lattice geometries that cannot be produced using other manufacturing processes. Plate lattices are a type of lattice structure composed of intersecting plates and are of interest in impact applications because of their potential for having high energy absorption at low relative weights. Mechanical properties of lattices including strength and relative density can be tailored for an application by selecting specific unit cell topologies and dimensions. Here, we study different plate lattice topologies and their mechanical performance in impact applications. Explicit dynamic finite element simulations are developed in ANSYS simulation software, and plate thickness and unit cell size are varied to predict optimal lattice geometries. From these simulations, candidate lattice samples are fabricated using laser powder bed fusion. Compression and ballistic tests are conducted on samples to validate simulation models and determine lattice strengths.
9:30 AM
Optimized Dissolvable Support Design for 316L Stainless Steel Produced by Laser Powder Bed Fusion: Shawn Hinnebusch1; David Anderson1; Kevin Glunt1; Robert Hoffman2; Owen Hildreth2; Albert To1; 1University of Pittsburgh; 2Colorado School of Mines
Creating parts by laser powder bed fusion (L-PBF) process is challenging as support material is usually required for complex parts. As L-PBF can only use one material, creating a dissolvable support structure has many challenges. To have a dissolvable support, a low-density structure is usually required, but this type of structure typically has cracking and high distortion due to the presence of high residual stress. This work proposes a lattice structure design that can ensure printability while maintaining fluid flow across all the support to allow the structure to fully dissolvable. Using a hybrid lattice structure, the overall mass is minimized while still meeting the criteria for residual stress. Also, employing a self-terminating solution, the part retains the material while the support structure can be fully dissolved.
9:50 AM Break
10:10 AM
Permeable Additive Manufacturing (PermiAM) for Rocketry: Adam Polizzi1; Kimberly Devore2; Matthew Kuhns2; Jeremy Iten1; 1Elementum 3D; 2Masten Space Systems
PermiAM is a patent pending method for creating variable-porosity materials in situ with fully dense parts. Teams of experts from Masten Space Systems and Elementum 3D have been developing the technology via NASA SBIRs in L-PBF machines, along with internal funding, to eliminate the need for secondary processing of the permeable bodies for propulsion equipment. In addition, PermiAM is completely material agnostic. Applied to rocket injection componentry, PermiAM enables transpiration cooling and has been described as ‘game changing’ by industry experts. Not only has PermiAM promoted a 60% cost savings on transpiration injectors but can also be manufactured 92% faster.During a 65 second hot fire test and a combustion temperature on 6100°F combustion the temperature, the PermiAM injector face remained at 380°F. Additionally, PermiAM has accumulated a total of more than 800 seconds of hot fire testing across multiple materials in aluminum, nickel, and copper material sets.
10:30 AM
Laser-based 4D Printing of Ni-Mn-Ga Magnetic Shape Memory Alloys Lattice Structures: Anastassia Milleret1; Ville Laitinen2; Nour-eddine Fenineche3; Moataz Attallah1; 1University of Birmingham; 2Lappeenranta-Lahti University of Technology; 3UTBM
This study investigates the influence of L-PBF process parameters (laser power, scan speed, hatch spacing and scanning strategy) on the relative density, microstructure and geometrical integrity of lattice specimens made from a gas atomised Ni-Mn-Ga powder doped with excess Mn. The specimens showed a homogenous chemical composition, and crystal structure consisting of seven-layered modulated (14M) martensite. After homogenisation at 1040 °C for 24 h, the specimens exhibited typical composition dependent phase transformations and a bamboo-like microstructure consisting of large grains spanning the thickness of the struts. The grains show a microstructure with typical stripe-like surface relief originating from martensitic twins. In addition, the influence of the lattice geometries on the magnetic properties is investigated. Further work will focus on developing a new design and post-processing routes to enhance the magnetic properties and to control the crystallographic texture.
10:50 AM Cancelled
Mechanical Behavior of 7050 Aluminum AM Lattice Structures: Ben Dimarco1; Noah Gula1; Jeremy Seidt1; Edward Herderick1; 1The Ohio State University
Complex cellular and lattice structures are an exciting field of materials development offering revolutionary opportunities in medical devices, lightweighting, and impact protection. Additive manufacturing (AM) is uniquely suited to produce lattice structures and there has been a synergistic development cycle between the lattice design community and AM. However, there is an unmet need to understand how the lattice structure integrates with the surrounding material. This is motivated by the demanding applications of the defense, space, medical, and commercial sectors. The key objective of this work is to successfully design, integrate, and characterize the behavior of metal lattice structures to a part boundary region. This presentation will include finite element analysis simulation results, LPBF printing of 7050 Aluminum lattice samples, and mechanical test results using 3D DIC. The presentation will conclude with a perspective on continued development toward qualification and certification requirements for metal printed lattice structures in aerospace/space applications.