Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Additively Manufacturing”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Al6061-RAM2 Development and Hot-Fire Testing using Additive Manufacturing Laser Powder Directed Energy Deposition for Liquid Rocket Engine Channel-Cooled Nozzles

Aluminum 6061-RAM2 is a high-strength aluminum feedstock developed for additive manufacturing (AM)processes. This alloy leverages Reactive Additive Manufacturing (RAM) technology. The RAM aluminum alloys were developed to be weldable—therefore printable—while equaling or exceeding strength properties of high strength wrought aluminum alloys. NASA and industry partners developed Laser Powder Directed Energy Deposition (LP-DED)additive manufacturing of Al6061-RAM2 for use in aerospace applications. Efforts included establishing build parameters, characterizing the alloy, fabricating components, and completing hot-fire testing of complex internal channel-cooled nozzles. These efforts are to address the growing need for large-scale parts using high-performance light-weight materials. Two rocket engine nozzles were fabricated using LP-DED Al6061-RAM2 that included integral cooling channels. The Al6061-RAM2 has completed process development and initial properties were established. This paper provides an overview of the LP-DED process development, material characterization and properties, component manufacturing, supplemental development, and hot-fire testing. Results from hot-fire testing are provided for a lander-class 31kN (7,000lbf)thrust engine using Liquid Oxygen (LOX)/Liquid Hydrogen(LH2) and LOX/Methane(LCH4).

Al6061-RAM2↗
NASA NTRSDate not supplied

Al6061-RAM2 Development and Hot-Fire Testing using Additive Manufacturing Laser Powder Directed Energy Deposition for Liquid Rocket Engine Channel-Cooled Nozzles

Aluminum 6061-RAM2 is a high-strength aluminum feedstock developed for additive manufacturing (AM)processes. This alloy leverages Reactive Additive Manufacturing (RAM) technology. The RAM aluminum alloys were developed to be weldable—therefore printable—while equaling or exceeding strength properties of high strength wrought aluminum alloys. NASA and industry partners developed Laser Powder Directed Energy Deposition (LP-DED)additive manufacturing of Al6061-RAM2 for use in aerospace applications. Efforts included establishing build parameters, characterizing the alloy, fabricating components, and completing hot-fire testing of complex internal channel-cooled nozzles. These efforts are to address the growing need for large-scale parts using high-performance light-weight materials. Two rocket engine nozzles were fabricated using LP-DED Al6061-RAM2 that included integral cooling channels. The Al6061-RAM2 has completed process development and initial properties were established. This paper provides an overview of the LP-DED process development, material characterization and properties, component manufacturing, supplemental development, and hot-fire testing. Results from hot-fire testing are provided for a lander-class 31kN (7,000lbf) thrust engine using Liquid Oxygen (LOX)/Liquid Hydrogen (LH2) and LOX/Methane (LCH4).

Al6061-RAM2↗
DOE OSTI2024

Additive manufacturing of sandwich panels with continuous fiber reinforced high modulus composite facings

Abstract An improved approach consisting of a combination of fiber placement and fused filament fabrication is introduced for the additive manufacture (AM) of structural grade sandwich beams. Here, sandwich beams are additively manufactured using in‐situ deposition and consolidation of continuous fiber unidirectional facings made from a commingled yarn system of e‐glass fiber (~50% vol.) and amorphous PET, and a hexagonal honeycomb core structure made from PETG. Both facings and the sandwich core are manufactured on a single machine, in one sequence (skin‐core‐skin), employing the benefit of matrix compatibility to create autohesion at the interfaces. Flexural and transverse shear rigidity are determined experimentally and compared with analytical predictions and show correlation to within 3%. Flexural strength and core shear strength are also measured. Post‐mortem examinations show that core fracture and core facing debond were the dominant failure mode in flexure. Single cantilever beam tests were performed to evaluate core facing debond toughness. Subsequently, surface preheat using infrared heaters was utilized to increase autohesion between core and facing. The results show debond toughness was increased 4 times using infrared heating. This research effort presents a manufacturing approach that has the potential for the AM of stiff, well bonded, structural grade sandwich beams, in an integrated sequence, employing in‐situ consolidation to the facings, without the need for the use of intermediate adhesives for skin‐to‐core bonding. Highlights An improved additive manufacturing technique for making sandwich panels is developed. Sandwich panel facings have fiber volume fractions of approximately 50%. Surface preheat improves core‐to‐facing debond toughness by a factor of 4. Top and bottom facings are consolidated during manufacture leading to better properties. Experimental results are compared to analytical predictions and show good correlation.

17 WIND ENERGY↗
NASA NTRS2018

Characterizing Performance of Additively Manufacturing Regenerative Cooled Combustion Chambers Through Hot Fire Testing

NASA Marshall Space Flight Center (MSFC) has developed several additive manufactured regenerative cooled combustion chambers from 2014 to present. Chambers have been constructed using the Selective Laser Melting (SLM) powder bed additive manufacturing (AM) technique. The materials used for the chambers has varied from Inconel 718, Inconel 625, GRCop-84, and C18150 metal alloys. The surface finish and build techniques used to successfully manufacture combustion chambers using the SLM AM result in as built surface finish and off nominal geometric features. This paper discusses and reviews the effects of surface roughness, flow area, and hydraulic performance of regenerative cooled combustion chambers. The thrust chambers designs tested ranged from 200 to 1,400 psia producing 1,000 to 35,000 lbf thrust. Empirical data from four test campaigns will be reviewed and related to design modeling parameters such as pressure drop, surface roughness, and actual fluid flow geometry. Correlation results with simple 2-D CFD modeling will also be presented. The goal of the work is to better understand how the finished additive manufactured component characteristics inside internal features can effect regenerative cooling chamber design. Adjustments to design methodology will be discussed and recommended based on the above results.

Garcia, C. P.↗
NASA NTRS2018

Space Environmental Effects on Additively Manufactured Materials

Space simulations including thermal vacuum, atomic oxygen, and ultraviolet radiation were performed to study the durability of various additively manufactured materials. In addition to ground simulations, additively manufactured materials were selected for a one-year flight on the Materials on International Space Station Experiment (MISSE) Flight Facility. The space environment is composed of atomic oxygen, ultraviolet radiation, protons, electrons, meteoroid/space debris impacts, thermal cycling, and hard vacuum. An improved UV sensor is also discussed.

Finckenor, M. M.↗
NASA NTRS2019

Additive Manufacturing Development and Hot-Fire Testing of Liquid Rocket Channel Wall Nozzles Using Blown Powder Directed Energy Deposition Inconel 625 and JBK-75 Alloys

Additive manufacturing (AM) is being investigated at NASA and across much of the rocket propulsion industry as an alternate fabrication technique to create complex geometries for liquid engine components that offers schedule and cost saving opportunities. The geometries that can be created using AM offer a significant advantage over traditional techniques. Internal complexities, such as internal coolant channels for combustion chambers and nozzles that would typically require several operations to manufacture traditionally can be fabricated in one process. Additionally, the coolant channels are closed out as a part of the AM build process, eliminating the complexities of a traditional process like brazing or plating. The primary additive manufacturing technique that has been evaluated is powder bed fusion (PBF), or selective laser melting (SLM), but there is a scale limitation for this technique. There are several alternate additive manufacturing techniques that are being investigated for large-scale nozzles and chambers including directed energy deposition (DED) processes. A significant advantage of the DED processes is the ability to adapt to a robotic or gantry CNC system with a localized purge or purge chamber, allowing unlimited build volume. This paper will discuss the development and hot-fire testing of channel-cooled nozzles fabricated utilizing one form of DED called blown powder deposition. This initial development work using blown powder DED is being explored to form the entire channel wall nozzle with integral coolant channels within a single AM build. Much of this development is focused on the design and DED-fabrication of complex and thin-walled features and on characterization of the materials properties produced with this techniques in order to evolve this process. Subscale nozzles were fabricated using this DED technique and hot-fire tested in Liquid Oxygen/Hydrogen (LOX/GH2) and LOX/Kerosene (LOX/RP-1) environments accumulating significant development time and cycles. The initial materials that were evaluated during this testing were high-strength nickel-based Inconel 625 and JBK-75. Further process development is being completed to increase the scale of this technology for large-scale nozzles. This paper will summarize the general design considerations for DED, specific channel-cooled nozzle design, manufacturing process development, property development, initial hot-fire testing and future developments to mature this technology for regeneratively-cooled nozzles. An overview of future development at NASA will also be discussed.

Gradl, Paul R.↗
DOE OSTI2021

Composites and additive manufacturing for high-field coil supports for stellarators

The utilization of composites layered on an additive manufactured substrate, for the production of coil supports for modular coils in small or middle size experimental stellarators is assessed. The focus of the study is a monolithic coil support comprising the coils of a half-period of a stellarator, somewhat similar to the ones in UST_2 and ARIES-CS stellarators. However, the concept may be applicable to quasi-monolithic coil supports (coil forms of NCSX type) or individual coil casings (W7-X type).Coil supports for stellarators require high precision, stiffness and strength for large contorted parts. Traditionally, monolithic coil supports are produced by steel casting/forging and final machining. This production method and material gives accurate, stiff and strong coil supports, but the method may be expensive for monolithic supports due to the geometrical complexity and required accuracy of the structure. In relation to those matters, this work investigates whether a monolithic coil support comprising an additive manufactured resin substrate, which is externally (outward from the coils) surrounded with a thick layer of fibre-reinforced resin, may achieve enough strength and stiffness under middle/high magnetic fields. Finite element calculations are produced to obtain the direction of the principal stresses and their values in compression and tension at different areas of the monolithic support, which is relevant for anisotropic materials. The feasibility of directional application of (carbon) fibres on the winding surface of the stellarator outward from the coils is experimentally tested on a scaled-down additively manufactured prototype of a monolithic support. The strength and stiffness of the composite structure appears sufficient for common magnetic fields in experimental stellarators, and the 3D-composite design and manufacturing was technically feasible.

Queral, Vicente↗
NASA NTRS2015

A Decision-Support Model for Selecting Additive Manufacturing Versus Subtractive Manufacturing Based on Energy Consumption

This paper presents a simple computational model for determining whether additive manufacturing or subtractive manufacturing is more energy efficient for production of a given metallic part. The key discriminating variable is the fraction of the bounding envelope that contains material – i.e. the volume fraction of solid material. For both the additive process and the subtractive process, the total energy associated with the production of a part is defined in terms of the volume fraction of that part. The critical volume fraction is that for which the energy consumed by subtractive manufacturing equals the energy consumed by additive manufacturing. For volume fractions less than the critical value, additive manufacturing is more energy efficient. For volume fractions greater than the critical value, subtractive manufacturing is more efficient. The model considers the entire manufacturing lifecycle – from production and transport of feedstock material through processing to return of post-production scrap for recycling. Energy consumed by processing equipment while idle is also accounted for in the model. Although the individual energy components in the model are identified and accounted for in the expressions for additive and subtractive manufacturing, values for many of these components may not be currently available. Energy values for some materials’ production and subtractive and additive manufacturing processes can be found in the literature. However, since many of these data are reported for a very specific application, it may be difficult, if not impossible, to reliably apply these data to new process-material manufacturing scenarios since, very often, insufficient information is provided to enable extrapolation to broader use. Consequently, this paper also highlights the need to develop improved knowledge of the energy embodied in each phase of the manufacturing process. To be most valuable, users of the model should determine the energy consumed by their manufacturing process equipment on the basis of energy-per-unit-volume of production for each material of interest – considering both alloy composition and form. Energy consumed during machine idle per unit time should also be determined by the user then scaled to specific processing scenarios. Energy required to generate feedstock material (billet, plate, bar, wire, powder) must be obtained from suppliers.

J K Watson↗
NASA NTRSDate not supplied

Adaptation of Metal Additive Manufacturing Processes for the International Space Station

The In-Space Manufacturing (ISM) project at NASA Marshall Space Flight Center, in a partnership with the company, Made in Space, has previously investigated 3D printing of polymer materials on-orbit. In recent years, the project has begun exploring the potential for metal additive manufacturing (AM) on future space missions to reduce logistics and enable point-of-use manufacturing for sparing and repair. This paper provides an overview of constraints for demonstrating a manufacturing process on the International Space Station (ISS) as well as information on previous trades of available metal AM processes and their potential for in-space use. There are currently two processes in development as payloads for an ISS technology demonstration: wire+arc additive manufacturing (the Vulcan payload from Made in Space, Inc.) and bound metal additive manufacturing (the Fabrication Laboratory from Techshot, Inc). An update on both of these systems, key results to date, and future development efforts will be presented. Relevant modeling work, performed by NASA Ames Research Center, to evaluate operation of certain aspects of the bound metal AM process in a microgravity environment will also be summarized.

in-space manufacturing↗
DOE OSTI2023

Printability and Overall Cooling Performance of Additively Manufactured Holes With Inlet and Exit Rounding

Abstract To improve cooling effectiveness of gas turbine hardware, various film cooling hole shapes have previously been researched. Unique design modifications have recently been made possible through the design freedom allotted by additive manufacturing (AM). As one example, creating a rounded inlet for a film-cooling hole can mitigate separation at the inlet. This study explores various geometric features by exploiting the uses of additive manufacturing for shaped film cooling holes at engine scale. Both printability and cooling performance were evaluated. Resulting from this study, additively manufactured holes with hole inlet and exit rounding were printed with some variations from the design intent (DI). The largest deviations from the design intent occurred from dross roughness features located on the leeward side of the hole inlet. The measured overall effectiveness indicated that an as-built inlet fillet decreased in-hole convection as well as decreased jet mixing compared to the as-built sharp inlet. Including an exit fillet, which prevented an overbuilt diffuser exit, was also found to decrease jet mixing. A particular insight gained from this study is the importance of the convective cooling within the hole to the overall cooling performance. In-hole roughness, which is a result of additive manufacturing, increased convective cooling within the holes but also increased jet mixing as the coolant exited the hole. The increased jet mixing caused low overall effectiveness downstream of injection.

Engineering↗
DOE OSTI2025

Volumetric Additive Manufacturing of Dormant Catalytic Chemistries to Generate Silicone Micro‐ and Millifluidic Devices and Instant Molds

Tomographic volumetric additive manufacturing (T‐VAM) rapidly prints solid objects within minutes, accessing photochemistries that are traditionally challenging for layer‐based additive manufacturing methods. This includes high‐viscosity materials, air‐free chemistries, and solid‐state systems. Catalytic chemistries are appealing as a pathway to engineering advanced materials, including tough thermosets, silicone elastomers, and complex block copolymers. However, photoactivated dormant catalytic chemistries, where the catalyst irreversibly activates upon exposure to light, are incompatible with typical tomographic VAM approaches. To address this limitation, a zero‐dose optimization strategy is devised to preserve dormant catalysts in desired regions by keeping them unexposed to light. VAM printed micro‐ and millifluidic devices and instant molds are successfully produced within minutes in silicones polymerized using photoactivated dormant platinum photohydrosilylation catalysts. The printed channels are programmed to be 500 and 2500 µm for the micro‐ and millifluidic devices, and print fidelity is assessed by X‐ray computed tomography. This work demonstrates the potential of zero‐dose optimization to expand the range of chemistries accessible for VAM, enabling the rapid fabrication of complex devices.

Additive Manufacturing↗
NASA NTRS2019

Additive Manufacturing of Oxide Dispersion Strengthened (ODS) Nickel-Based Superalloys

Additive manufacturing of oxide dispersion strengthened (ODS) Ni-based superalloys, via powder bed techniques, could enable near-net-shape manufacturing of intricately shaped components for aerospace applications. This has the potential to transform the design and manufacturing of hot sections of engines which face demands for ever-rising operating temperatures. The goal of this project is to lay the scientific foundation for additive manufacturing of ODS alloys. The objective of this poster is to present work to date as well as proposed future work.

Wilson, Laura G.↗
DOE OSTI2020

Investigation of the irradiation effects in additively manufactured 316L steel resulting in decreased irradiation assisted stress corrosion cracking susceptibility

While additive manufacturing (AM) is an area of increasing interest to the nuclear industry, there are significant research and development needs prior to successful implementation of additively manufactured components into reactors. AM steel behaves differently than traditional wrought material, as has been observed in numerous mechanical testing studies. The nuclear industry must also understand the material response to irradiation. This work examines the irradiation damage and the irradiation assisted stress corrosion cracking behavior (IASCC) of both proton irradiated AM and wrought 316L steel. For IASCC testing, specimens were strained to 4% plastic strain in a simulated boiling water reactor environment (288°C, 0.2 µS/cm). Transmission and scanning electron microscopy, confocal microscopy, and X-ray computed tomography were used to examine coupons of the material as well as tensile bars used in the IASCC testing. This work found that the wrought 316L was more susceptible to IASCC than the AM steel, however, some IASCC was observed in the AM steel when tested with the tensile axis parallel to the build direction. Electron microscopy has shown significantly fewer radiation induced voids formed in the AM steel. While the pre-existing pore network in the AM steel may act as a sink to point defects, this is not expected to be the major factor in the reduced swelling observed in the AM steel. The lower density of radiation induced voids was expected to contribute to the IASCC resistance by decreasing the localization of deformation in the irradiated specimens, however, severity of localized deformation in AM steel, measured in dislocation channel spacing and height, was similar or more severe to that found in wrought. In conclusion, the presence of severe cracking in the wrought specimens did not allow for a direct comparison of localized deformation severities between the AM and wrought steel.

Additive manufacturing↗
DOE OSTI2024

Utility of Big Area Additive Manufacturing for Part Production for Low-Head Hydropower

ORNL worked with Cadens, LLC to explore the use of additive manufacturing (AM) for the production of low-cost parts for low-head hydropower systems. Cadens develops design optimization software that leverages the flexible, low-cost, high-strength benefits of AM and composite materials, and operates a micro-hydro lab to test AM components in controlled environments. Until now Cadens’ tests have been limited in size to components that they can cost-effectively manufacture using local commercial systems. This project provided an opportunity for Cadens to scale up their modular AM hydropower parts using the capabilities of Big Area Additive Manufacturing (BAAM). This project was a success and resulted in the design and fabrication of several end use parts of a hydropower system using a Big Area Additive Manufacturing (BAAM) system. The fabricated parts include draft tube, thimble, runner housing mold, PVC end fitting and two PVC pipe supports. The components have been in use for more than three years without a 3D printed component failing.

13 HYDRO ENERGY↗
DOE OSTI2023

Load balancing for multi-beam additive manufacturing systems

As powder bed fusion (PBF) additive manufacturing (AM) becomes a more mature field, system configurations are gradually moving away from the classic single heat source, layer-by-layer system configurations towards unconventional system configurations that offer higher throughput. Higher throughput systems allow PBF systems to be considered for a larger variety of industrial applications. However, the inclusion of multiple heat sources, or beams, also increases the complexity of the control schemes needed. For multi-beam systems with overlapping fields of view, the distribution of workload, or load balancing, across these beams directly affects the total print time for a build. Additionally, the probability of any beam failing in a multi-beam system increases with the number of beams. While manual methods of load balancing and dealing with beam failures are reasonable for current generation multi-beam systems, as system configurations become more complex, manual methods will become prohibitively inefficient. Here, this paper introduces two different ways to load balance multi-beam systems of various configuration types, regardless of their complexity, which are highly performant. A consequence of this performance is the enablement of on-the-fly load balancing in the event a beam fails, thus improving system robustness.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Geometrical effects on the measured neutron residual stress in additively manufactured cold spray AA6061

Aluminum cold spray additive builds were made with varying wall widths and geometries to explore the effects of build geometry on residual stress development in the additively sprayed material. Deposition rates of over 750 g/hr were achieved without any cracking or delamination of the additively manufactured components. Neutron residual stress measurements revealed a maximum tensile residual stress of 41 MPa at the interface of the substrate and a maximum compressive residual stress of −35 MPa in the cold sprayed material. While there was not found to be significant residual stress changes between the cold sprayed walls, the cold sprayed cylinder had varying residual stress throughout the diameter with the outer diameter having a higher tensile residual stress than the interior. The low residual stress and minimal geometrical dependency demonstrate further part size is possible without concerns for component failure in AA6061. The application of common coating residual stress models to full scale additive builds is evaluated and discussed. The lack of residual stress evolution was studied by in-situ coating property measurement that revealed that the deposition stress of the AA6061 sprays reduced with increased layer thickness. In conclusion, this study provides insight into the evolution of residual stress in cold spray additive components and how both the mechanics and material responses differ from coatings.

Additive manufacturing↗
DOE OSTI2026

Microstructure Validation of Graph Theory Model-Derived Cooling Rates in the Wire Arc Additive Manufacturing of ER70S-6 Steel

Wire arc additive manufacturing (WAAM) enables high-rate fabrication of large metallic components, but spatial variations in thermal history can lead to microstructural heterogeneity that requires efficient process models to evaluate. This study evaluates whether cooling rates extracted from a graph theory model (GTM)-based thermal simulation are consistent with the microstructural evolution observed in an ER70S-6 WAAM wall. Thermal histories from the model were analyzed at selected build heights, and cooling rates were extracted from the final thermal excursion through the austenite phase field. Microstructures at corresponding locations were characterized using electron backscatter diffraction (EBSD) to quantify grain size distributions, and pearlite interlamellar spacing was used as an additional indicator of cooling behavior. The modeled cooling rates were highest near the substrate and generally decreased with build height, consistent with the observed reduction in the fine grain fraction and the progressive shift in the grain size distribution as build height increased. Pearlite spacing trends also supported the modeled cooling rate variation. These results indicate that GTM-derived thermal histories can be post-processed into metallurgically meaningful cooling rate estimates for WAAM steel builds and linked to dataset specific empirical grain size distribution relationships for process–thermal history–microstructure assessment.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Additive manufacturing of silicon carbide for nuclear applications

Additive manufacturing (AM) is a rapidly evolving technology being considered for nuclear applications. A special focus on AM to fabricate nuclear-grade silicon carbide (SiC) is explored in this paper. First, we present currently available AM processing options for SiC. AM methods commonly used for other ceramics, in which the feedstocks are forms of polymers, powders, and/or reactive chemical vapors, are also applicable to SiC. SiC phases are formed by pyrolysis of pre-ceramic polymer, direct reaction of powder precursors, sintering of SiC powders, or chemical vapor deposition/infiltration. Second, we discuss how the different microstructures of SiC materials fabricated by various processing methods affect their behavior in nuclear environments. Third, we discuss state-of-the-art AM technologies for the fabrication of relatively pure SiC, which show great potential to retain its strength under neutron irradiation: (1) binder jet printing followed by chemical vapor infiltration, (2) laser chemical vapor deposition, and (3) selective laser sintering of SiC powders.

36 MATERIALS SCIENCE↗