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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.

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At least 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

AMES: MS and MENG in Advanced Manufacturing for Energy at the University of Connecticut (Final Technical Report)

The objective of the project is to develop and implement an advanced degree program (MS and MENG in Advanced Manufacturing for Energy Systems, AMES) responding to the long-term workforce and technology requirements of the nation’s advanced energy products manufacturing industry. The program provided an industry relevant research experience by leveraging existing energy (e.g. fuels, power electronics, electrochemical power sources) and advanced manufacturing (e.g. additive manufacturing, composites, sensing) research at UConn funded by federal and state agencies, and industry, as well as through our industry partnerships. The trainees have joined research teams, advised by faculty with relevant research interests and expertise and were co-advised by industrial mentors. The AMES program have developed a truly interdisciplinary curriculum, first graduate degree program at UConn School (now College) of Engineering not housed in an academic department, with concentrations focusing on various challenges in advanced manufacturing for energy systems, e.g. advanced materials and processing. The project also developed new courses focusing on common technical and professional skills, and integrated various components for an industry relevant training. The program has admitted 29 Master of Science (MS) students since inception in January 2019. Twenty six of these students were AMES fellows, who have received partial funding from DoE through this project. The program far exceeded the goal of admitting at least five new MS (with thesis) students. All students were required to complete a thesis (M.S.) or a capstone (M.Eng.) project that are defined in collaboration with industry partners to ensure industrial relevancy, addressing a current industrial challenges. Industrial mentors also participated in advising the students in their research. AMES fellows, in addition were also required to complete an industrial internship for further industrial experience.

36 MATERIALS SCIENCE↗
NASA NTRSDate not supplied

Process Development and Testing for Lunar Habitats

Non-metallic solutions for Lunar bases are appealing due to their light weight and ability to block many forms of radiation. Composite materials made from different combinations of these non-metallic materials enable effective mating of dissimilar materials for strong structures such as pressurized habitats. Inserting and manufacturing composite structural materials on the Moon presents several challenges, however: the oxygen levels inside pressurized habitats will be relatively high, radiation that is blocked causes damage and the lack of atmosphere results in a high-magnitude negative pressure environment. In the past two years, the Materials and Processes Lab (EM01) invested in two internal research and development (IRAD) proposals for testing and procurement of composite materials. One proposal endeavors to determine flammability and radiation damage of various composite materials with a focus on carbon fiber and ultra-high molecular weight polyethylene (UHWMPE). The other proposal enables procurement of chopped fiber spray equipment materials which will be used to develop a novel technique for chopped UHMWPE fiber layup, similar to the chopped fiberglass layups used for making large structures such a boat hulls and hot tubs.

Composite↗
NASA NTRSDate not supplied

Improvements to Stitching Controls for Manufacturing Advanced Stitched Composites

Stitched composites have been extensively studied and have been shown to have benefits over unstitched composites for stiffened structures, including improved damage tolerance, reduced weight, and fewer fasteners. These benefits make stitched composites attractive from a performance perspective, however, the nature of stitching the preforms prior to infusion includes additional manufacturing steps and equipment compared to conventional resin infusion. Stitching of composite material structures at NASA Langley Research Center (LaRC) is performed at the Integrated Structural Assembly of Advanced Composites (ISAAC) facility using control algorithms developed by the lead author. Two deficiencies have been identified in the current control algorithms, and mitigations for these deficiencies were developed within the Hi-Rate Composite Aircraft Manufacturing (HiCAM) project and are presented herein. First, decoupling stitch translation and rotation takes more time for stitching since two robot operation control steps are executed for each stitch. Therefore, a method was developed to determine when to decouple the translation and rotation for stitching, which reduces stitch time by decoupling the operation control steps only when necessary to execute the stitch properly. Second, a correction to the sideslip stitching approach that eliminates a significant portion of the pre- and post-stitching activities was developed. The developed method adjusts the sideslip stitch angle based on the rotations of previous stitches to ensure that the width of the stitching seam remains constant along its length. Constant seam width eliminates observed overlap of the insertion and catcher thread portions for highly curved paths, which maintains the desired uniformity of through-the-thickness architecture along the seam and eliminates the local degradation of properties where the insertion needle is too close to, or crosses, the catcher needle portion of the seam.

stitching↗
NASA NTRS1989

Strength distribution of reinforcing fibers in a Nicalon fiber/chemically vapor infiltrated silicon carbide matrix composite

The strength distribution of fibers within a two-dimensional laminate ceramic/ceramic composite consisting of an eight harness satin weave of Nicalon continuous fiber within a chemically vapor infiltrated SiC matrix was determined from analysis of the fracture mirrors of the fibers. Comparison of the fiber strengths and the Weibull moduli with those for Nicalon fibers prior to incorporation into composites suggests that possible fiber damage may occur either during the weaving or during another stage of the composite manufacture. Observations also indicate that it is the higher-strength fibers which experience the greatest extent of fiber pullout and thus make a larger contribution to the overall composite toughness than do the weaker fibers.

Eckel, Andrew J.↗
DOE OSTI2023

THE IMPACT OF VISCOSITY ON MATERIAL TRANSITIONS IN LARGE FORMAT ADDITIVE MANUFACTURING OF POLYMER COMPOSITES

The need to produce complex geometries incompatible with traditional manufacturing techniques has fueled rapid growth in Large-Format Additive Manufacturing (LFAM). Printing of polymer composite materials have generated significant interest, but the production of Multi-Material (MM) structures with location-based material properties continues to be a challenge. Extrusion-based techniques have utilized multiple deposition heads to successfully print MM structures with both stiff and flexible regions, but these techniques often result in discrete material boundaries that concentrate stress and act as failure points. To avoid discrete interfaces, a novel dual-hopper configuration was developed for the Big Area Additive Manufacturing (BAAM) system that creates a blended material region within the structure. The ability to blend and freely switch between stiff polymer composites and flexible polymers enables printing of robust MM structures with site-specific properties. This study characterizes the influence of viscosity on a blended material transition between carbon fiber-filled acrylonitrile butadiene styrene (CF-ABS) and unfilled thermoplastic polyurethane (TPU), which have significantly different viscoelastic behaviors

Brackett, James↗
DOE OSTI2026

Volumetric Additive Manufacturing of Gradient Composition Glass

Advanced optics, such as lasers or cameras, are currently limited by geometric or compositional restrictions on the silica glass components that act as focusing or refracting lenses. Currently, these glass components must be made of one homogenous material in a range of shapes and sizes limited by a few specialized vendors. However, additional flexibility and customization of these optical components could significantly improve the performance of these devices and expand the design space available to optics engineers, as would the capability to locally change the optical properties of these glass components by changing the composition of the glass as a function of location. To this end, we have developed a method to print and process gradient composition glass, using volumetric additive manufacturing (VAM) and direct ink writing (DIW), on-site at Lawrence Livermore National Lab.

36 MATERIALS SCIENCE↗
NASA NTRS1991

Small Business Innovations (Fiber Optics)

Foster-Miller, Inc. Waltham, MA developed the In-Situ Fiber Optic Polymer Reaction Monitor which could lead to higher yields and lower costs in complex composite manufacturing. The monitor, developed under a Small Business Innovation Research (SBIR) contract with Langley Research Center, uses an infrared, fiber optic sensor to track the molecular vibrational characteristics of a composite part while it is being cured. It is the first analytical system capable of directly measuring the chemistry of advanced composite materials.

Source record↗
NASA NTRS1993

The effects of aircraft fuel and fluids on the strength properties of Resin Transfer Molded (RTM) composites

The resin transfer molding (RTM) process offers important advantages for cost-effective composites manufacturing, and consequently has become the subject of intense research and development efforts. Several new matrix resins have been formulated specifically for RTM applications in aircraft and aerospace vehicles. For successful use on aircraft, composite materials must withstand exposure to the fluids in common use. The present study was conducted to obtain comparative screening data on several state-ofthe-art RTM resins after environmental exposures were performed on RTM composite specimens. Four graphite/epoxy composites and one graphite/bismaleimide composite were tested; testing of two additional graphite epoxy composites is in progress. Zero-deg tension tests were conducted on specimens machined from eight-ply (+45-deg, -45-deg) laminates, and interlaminar shear tests were conducted on 32-ply 0-deg laminate specimens. In these tests, the various RTM resins demonstrated widely different strengths, with 3501-6 epoxy being the strongest. As expected, all of the matrix resins suffered severe strength degradation from exposure to methylene chloride (paint stripper). The 3501-6 epoxy composites exhibited about a 30 percent drop in tensile strength in hot, wet tests. The E905-L epoxy exhibited little loss of tensile strength (less than 8 percent) after exposure to water. The CET-2 and 862 epoxies as well as the bismaleimide exhibited reduced strengths at elevated temperature after exposure to oils and fuel. In terms of the percentage strength reductions, all of the RTM matrix resins compared favorably with 3501-6 epoxy.

Falcone, Anthony↗
DOE OSTI2024

Digital Multiphase Composites via Additive Manufacturing

Abstract Mechanical properties of traditional engineering materials are typically coupled to each other, presenting a challenge to practitioners with multi‐dimensional material property requirements. In this work, continuous, independent control over multiple mechanical properties is demonstrated in composite materials realized using additive manufacturing. For the first time, composites additively manufactured from rigid plastic, soft elastomer, and liquid constituents are experimentally characterized, demonstrating materials which span four orders of magnitude in modulus and two orders of magnitude in toughness. By forming analytical mappings between relative concentrations of constituents at the microscale and resulting macroscale material properties, inverse material design is enabled; the method is showcased by printing artifacts with prescribed toughness and elasticity distributions. The properties of these composites are placed in the context of biological tissues, showing they have promise as mechanically plausible tissue mimics.

Smith, Lawrence T.↗
NASA NTRS2008

Water-Based Coating Simplifies Circuit Board Manufacturing

The Structures and Materials Division at Glenn Research Center is devoted to developing advanced, high-temperature materials and processes for future aerospace propulsion and power generation systems. The Polymers Branch falls under this division, and it is involved in the development of high-performance materials, including polymers for high-temperature polymer matrix composites; nanocomposites for both high- and low-temperature applications; durable aerogels; purification and functionalization of carbon nanotubes and their use in composites; computational modeling of materials and biological systems and processes; and developing polymer-derived molecular sensors. Essentially, this branch creates high-performance materials to reduce the weight and boost performance of components for space missions and aircraft engine components. Under the leadership of chemical engineer, Dr. Michael Meador, the Polymers Branch boasts world-class laboratories, composite manufacturing facilities, testing stations, and some of the best scientists in the field.

Source record↗
DOE OSTI2021

Resin transfer molding systems and control logic for manufacturing fiber-reinforced composite parts

Presented are manufacturing control systems for fabricating composite-material structures, methods for making/operating such systems, and resin transfer molding techniques for ameliorating race-tracking effects in fiber-reinforced polymer panels. A method for forming a composite-material construction includes confirming, via a system electronic control unit (ECU), that a fiber-based preform is placed in a mold cavity and that opposing mold segments of the molding apparatus are sealed together. A filler, such as a compressible bladder, a cluster of spring-biased pins, or a spray-chopped fiber bed, is introduced into a void between the fiber-based preform and a tool face of one mold segment to thereby eliminate an unwanted resin race track. The system ECU commands a resin pump to inject resin through a primary gate of the molding apparatus and into the mold cavity to thereby impregnate the fiber-based preform with the resin. One or more vents operate to evacuate air from the mold.

Rodgers, William R.↗
DOE OSTI2022

Hydrogen Storage System Cost Analysis (2017-2021) (Final Report)

This final technical report summarizes hydrogen storage system cost analysis results from 2017-2021. Results include onboard hydrogen storage system costs for light-duty vehicles, medium-duty vehicles, heavy-duty vehicles, class 8 long haul trucks, and passenger buses. Multiple storage systems are included, primarily focusing on compressed and cryo-compressed hydrogen in Type 3 and Type 4 storage systems. Additional analysis includes large-scale gaseous and liquid hydrogen storage at refueling stations in tube trailers and Dewars; advanced materials-based storage systems such as metal organic frameworks and metal hydrides; and a baseline setting analysis of compressed natural gas storage systems in support of the Institute for Advanced Composites Manufacturing Initiative (IACMI). Analyses were primarily conducted using a Design for Manufacture and Assembly ® methodology, which is a bottom-up process-based approach to estimating factory costs. Multiple annual production rates are reported to project high-volume costs relevant to mature markets.

08 HYDROGEN↗
NASA NTRS2005

Comparison of Elevated Temperature Tensile Properties and Fatigue Behavior of Two Variants of a Woven SiC/SiC Composite

Tensile properties (elastic modulus, proportional limit strength, in-plane tensile strength, and strain at failure) of two variants of a woven SiC/SiC composite, manufactured during two separate time periods (9/99 and 1/01), were determined at 1038 and 1204 C by conducting tensile tests on specimens machined from plates. Continuous cycling fatigue tests (R = 0.05) and 20 cpm) were also conducted at the same two temperatures on specimens from both composites. In this study, average tensile properties, 95% confidence intervals associated with the tensile properties, and geometric mean fatigue lives of both composite materials are compared. The observed similarities and differences in the tensile properties are highlighted and an attempt is made to understand the relationship, if any, between the tensile properties and the fatigue behaviors of the two woven composites.

Kalluri, Sreeramesh↗
NASA NTRS2015

Composite Characterization Using Laser Doppler Vibrometry and Multi-Frequency Wavenumber Analysis

NASA has recognized the need for better characterization of composite materials to support advances in aeronautics and the next generation of space exploration vehicles. An area of related research is the evaluation of impact induced delaminations. Presented is a non-contact method of measuring the ply depth of impact delamination damage in a composite through use of a Scanning Laser Doppler Vibrometer (SLDV), multi-frequency wavenumber analysis, and a wavenumber-ply correlation algorithm. A single acquisition of a chirp excited lamb wavefield in an impacted composite is post-processed into a numerous single frequency excitation wavefields through a deconvolution process. A spatially windowed wavenumber analysis then extracts local wavenumbers from the wavefield, which are then correlated to theoretical dispersion curves for ply depth determination. SLDV based methods to characterize as-manufactured composite variation using wavefield analysis will also be discussed.

Juarez, Peter↗
NASA NTRS1975

Reliability after inspection

The investigation is concerned with the derivation of relationships between the probability of having manufacturing defects, the probability of detecting a flaw, and the final reliability. Equations for the simple situation in which only one flaw can be present are used to introduce the relationships in a Bayes' theorem approach to the assessment of the final reliability. Situations which are prevalent in composites manufacturing are considered. Attention is given to a case involving the random occurrence of flaws on a laminate surface.

Davidson, J. R.↗
NASA NTRS2011

Fiber-Reinforced Reactive Nano-Epoxy Composites

An ultra-high-molecular-weight polyethylene/ matrix interface based on the fabrication of a reactive nano-epoxy matrix with lower surface energy has been improved. Enhanced mechanical properties versus pure epoxy on a three-point bend test include: strength (25 percent), modulus (20 percent), and toughness (30 percent). Increased thermal properties include higher Tg (glass transition temperature) and stable CTE (coefficient of thermal expansion). Improved processability for manufacturing composites includes faster wetting rates on macro-fiber surfaces, lower viscosity, better resin infusion rates, and improved rheological properties. Improved interfacial adhesion properties with Spectra fibers by pullout tests include initial debonding force of 35 percent, a maximum pullout force of 25 percent, and energy to debond at 65 percent. Improved mechanical properties of Spectra fiber composites (tensile) aging resistance properties include hygrothermal effects. With this innovation, high-performance composites have been created, including carbon fibers/nano-epoxy, glass fibers/nano-epoxy, aramid fibers/ nano-epoxy, and ultra-high-molecularweight polyethylene fiber (UHMWPE).

Zhong, Wei-Hong↗
DOE OSTI2020

Economic and environmental impacts of a non-traditional combined heat and power system for a discrete manufacturing facility

Combined heat and power (CHP) is an electricity generation strategy that benefits all sides with a vested interest in the nations’ energy future. The technology allows for the efficient production of electricity and heat, which in turn reduces the carbon footprint and energy costs of a facility with significant heat and electricity loads. This paper investigates, through a detailed dynamic simulation, how a highly non-traditional CHP facility can leverage those forces to economically and environmentally benefit. Four system configurations of a composites manufacturing facility, one existing and three proposed systems, including two CHP configurations and one combined cooling, heating, and power (CCHP) configuration are evaluated from both economic and environmental views. The three proposed configurations are based on a 600 kW microturbine as the primary mover. The dynamic model showed great potential to capture the dynamics of the system configurations including the dynamics of temperature, oven exhaust fraction, electrical efficiency, and overall efficiency of the system configurations. All 3 CHP systems have a payback period between 8.03 and 8.33 years. The proposed system configurations reduce up to 22.7% of the CO 2 emission compared to the existing facility, supplying the demands in a cleaner manner.

42 ENGINEERING↗