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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 433 records · Page 24
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Recycling Disassembled Automotive Plastic Components for New Vehicle Components: Enabling the Automotive Circular Economy

As the automotive industry increasingly relies on plastic components to meet fuel efficiency and emissions targets, the challenge of managing end-of-life vehicle (ELV) plastics continues to grow. Currently, more than 80% of ELV plastics in the U.S. are landfilled due to limited economic incentives and technical barriers to recycling. This study examines a mechanical recycling pathway for thermoplastic components disassembled from ELVs and assesses their usability for reintegration into new vehicle parts. Four representative materials were chosen based on material labels embedded in recovered parts and aligned with their virgin industrial equivalents: polypropylene (PP), 10% talc-filled PP (PP-T10), 20% talc-filled PP (PP-T20), and a 20% glass-/mineral-filled polyamide (PA6 + GF7 + MF13). The materials underwent shredding, drying, and injection molding before being characterized by particle size analysis, density measurement, thermal analysis (TGA, DSC), mechanical testing, and heat deflection temperature (HDT) evaluation. The results in this work indicated that minor differences in crystallinity were observed and small differences between model materials and ELV materials could have contributed to these changes. Mechanical testing revealed that neat polypropylene suffered a 15–20% reduction in stiffness and tensile strength, but talc-filled polypropylene and glass/mineral-filled nylon retained >90% of their modulus, strength, and heat deflection temperature values relative to virgin controls. Differences between virgin and ELV materials could have been attributed to use life degradation, contamination during use life, or even chemical/processing differences in model materials and ELV materials. However, these findings suggest that mechanically recycled, disassembled ELV plastics can retain sufficient structural performance to support circularity efforts in the automotive sector.

automotive recycling↗
NASA NTRS2016

Category B Plastic Pane Testing for JSC 66320 Rev A Requirements Verifiable Through Acceptance Testing

JSC 66320, Revision A, Optical Property Requirements for Glasses, Ceramics, and Plastics in Spacecraft Window Systems, lists several quantitative requirements that spacecraft windowpanes must meet. Recently, we were asked to establish a capability at the Kennedy Space Center to perform these measurements on category B plastic panes, i.e., plastic panes that could be used on a spacecraft for long-focal-length photography and piloting. Two of the criteria, normal wavefront and 30-degree wavefront attributes, can be measured with existing equipment and processes (see NASA TM NESC-RP-14-00951, April 2016) and are not discussed in this document. However, the other six criteria-haze, wedge angle, birefringence, reflectance, transmittance, and color balance-required substantial development and are the subject of this document. In this document, we do not discuss the rationale behind the requirements, but we did engage in discussions with the authors of JSC 66320 in order to better understand the requirements and the verifications being imposed on windows and their testing. Accordingly, this document presents our best understanding of the requested requirements and verifications. We also present our methodology for performing each of the six measurements, along with applicable mathematics and a description, with photos, of the hardware used. In addition, we supply the results of a test on a low-quality in-house plastic window as an example of the system operation. Only requirements that can be met by acceptance test and analysis, as opposed to optical inspection, are considered in this document.

spaceflight windows↗
NASA NTRSDate not supplied

Uncertainty Reduction With Multi-Model Monte Carlo for Crystal Plasticity Simulations of Additively Manufactured Metals

In this work, multi-model Monte Carlo estimators are developed to reduce uncertainty in quantities of interest (QoIs) extracted from crystal plasticity simulations of additively manufactured (AM) metals. A significant concern in AM parts is uncertainty in mechanical properties caused in part by complex microstructures that arise from the AM process. Quantifying uncertainty in microstructure-sensitive behavior using experiments alone is costly, especially when mechanical allowables must be established. Quantitative relationships among microstructure, micromechanical metrics like slip accumulation, crack initiation, and failure are also difficult to capture with limited experiments. Crystal plasticity material models instead enable computational prediction of micromechanical stress and strain fields given a discretized microstructure. However, high-fidelity finely discretized crystal plasticity simulations are computationally expensive, while lower-fidelity models are less accurate and generally biased, making uncertainty quantification and reduction computationally difficult as well. Multi-model Monte Carlo methods leverage correlations between high- and low-fidelity models to produce unbiased estimators for QoIs with reduced uncertainty relative to standard Monte Carlo. Crystal plasticity QoIs considered in this work include yield strength and the mean and extreme values of micromechanical fields that are relevant to crack initiation. Multi-model Monte Carlo estimators are developed for each individual QoI and several groups of QoIs. The results of this work establish relationships among model correlations, sample allocation, and uncertainty reduction for different combinations of QoIs and demonstrate a trend of less uncertainty reduction as QoIs become more sensitive to local microstructure. Limitations from using pilot samples to estimate model covariances and train low-fidelity models are also addressed. The uncertainty reduction achieved by multi-model Monte Carlo is an important step toward using computational mechanics models to predict microstructure-sensitive crack initiation and failure in AM parts.

uncertainty quantification↗
DOE OSTI2019

Elastomer and Plastic Compatibility with a Pyrolysis-Derived Bio-Oil

The compatibility of fueling infrastructure elastomers and plastics in bio-oil and diesel fuel was determined by measuring the volume swell. The bio-oil was produced via fast pyrolysis of woody feedstocks. The elastomer materials included fluorocarbons, acrylonitrile butadiene rubbers, neoprene, polyurethane, neoprene, styrene butadiene (SBR) and silicone. The plastic materials included polyphenylene sulfide (PPS), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyoxymethylene (POM), POM copolymer, high density polyethylene (HDPE), polybutylene terephthalate (PBT), polypropylene (PP), polyethylene terephthalate glycol (PETG), polythiourea (PTU), four nylon grades, and four thermosetting resins. The majority of the elastomer and plastic materials exhibited higher volume expansion in bio-oil than in diesel. These elastomers and plastics had high polarity values which more closely align with the polarities of the bio-oil versus the diesel fuel. Conversely, SBR, silicone, HDPE, and PP are relatively nonpolar and this matches the low polarity of the diesel fuel, which resulted in higher volume expansion in diesel, rather than the bio-oil for these four polymers.

09 BIOMASS FUELS↗
DOE OSTI2017

Life-cycle analysis of fuels from post-use non-recycled plastics

Plastic-to-fuel (PTF) technology uses pyrolysis to convert plastic waste—especially non-recycled plastics (NRP)—into ultra-low sulfur diesel (ULSD) fuel. To assess the potential energy and environmental benefits associated with PTF technology, we calculated the energy, water consumption, and greenhouse gas emissions of NRP-derived ULSD and compared the results to those metrics for conventional ULSD fuel. For these analyses, we used the Greenhouse gases, Regulated Emissions and Energy use in Transportation (GREET®) model. Five companies provided pyrolysis process product yields and material and energy consumption data. Co-products of the process included char and fuel gas. Char can be landfilled, which, per the company responses, is the most common practice for this co-product, or it may be sold as an energy product. Fuel gas can be combusted to internally generate process heat and electricity. Sensitivity analyses investigated the influence of co-product handling methodology, product yield, electric grid composition, and assumed efficiency of char combustion technology on life-cycle greenhouse gas emissions. The sensitivity analysis indicates that the GHG emissions would likely be reduced up to 14% when it is compared to conventional ULSD, depending on the co-product treatment method used. NRP-derived ULSD fuel could therefore be considered at a minimum carbon neutral with the potential to offer a modest GHG reduction. Moreover, this waste-derived fuel had 58% lower water consumption and up to 96% lower fossil fuel consumption than conventional ULSD fuel in the base case. In addition to the comparison of PTF fuels with conventional transportation fuels, we also compare the results with alternative scenarios for managing NRP including power generation and landfilling in the United States.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

A Continuum Dislocation Dynamics Crystal Plasticity Approach to Irradiated Body-Centered Cubic α-Iron

Radiation-induced embrittlement of reactor pressure vessel (RPV) steels can potentially limit the operating life of nuclear power plants. Over extended exposure to radiation doses, these body-centered cubic (BCC) irons demonstrate irradiation damage. Here, we present a continuum dislocation density (CDD) crystal plasticity model to capture the interaction among dislocations and self-interstitial atom (SIA) loops in α-iron. We demonstrate the importance of modeling cross slip using a combined stochastic Monte Carlo approach and the role of slip system strength anisotropy in capturing stochastic cross slip interactions. Through these captured interactions, the CDD crystal plasticity model can capture both the stress response and the physical evolution of dislocations on different slip system planes. Single-crystal verification experiments are used to calibrate the CDD crystal plasticity model, and a set of simplified polycrystalline simulations demonstrates the model’s ability to capture the stress response from tensile experiments on α-iron.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Upcycling Real‐World Post‐Consumer Polyolefins Plastics Into Light Olefins Via Microwave‐Assisted Processing

The rapid accumulation of plastic waste, particularly post-consumer polyolefins (POs) pose severe environmental and economic challenges worldwide. Recycling of post-consumer POs remains inefficient due to difficulties in separating mixed plastics, complex additives compositions, and high processing costs, resulting in recycling rates of less than 9%. To address these critical issues, this study utilized an innovative microwave-assisted catalytic upcycling approach for the efficient upcycling of complex post-consumer POs mixtures into valuable light olefins. Using the microwave-assisted catalytic upcycling approach, gas yields reached up to 80 wt.% from post-consumer POs mixtures, accompanied by a high selectivity (>70 wt.%) toward valuable light olefins. The upcycling of POs under microwave conditions is fully invested, including additives in real-word plastics, mixtures of different POs, reusability of catalyst, and more. The microwave-assisted catalytic upcycling approach offers an efficient, scalable, and cost-effective solution for upcycling post-consumer plastic mixtures, thereby advancing the principles of a circular economy.

42 ENGINEERING↗
DOE OSTI2017

Plastic Deformation Processes Accompanying Stress Corrosion Crack Propagation in Irradiated Austenitic Steels

During stress corrosion crack propagation, stress values in the crack tip vicinity often exceed material yield stress limit. Plastic deformation processes may accompany and influence cracking. Here, stress corrosion crack propagation and deformation mechanisms were investigated using EBSD analysis. The investigated material was 304L Ti-enriched austenitic stainless steel irradiated to 10.4 dpa at 320°C in the BOR-60 fast reactor. Crack growth tests were conducted in a simulated Normal Water Chemistry (NWC) environment in the temperature range 288–320 °C using compact tension specimens. By analyzing crack trajectory and grain structure in the crack vicinity, it was established that grain orientation with respect to the acting stress direction was not a key factor controlling crack propagation. No crystallographic orientation susceptible to cracking was identified. Also, EBSD analysis revealed strong inhomogeneity in plastic strain distribution along the crack path. Most crack-adjacent grains remained virtually strain-free whereas few grains experienced strong plastic strain. These areas were presumed to be “plastic bridges” or “ductile ligaments.”

Gussev, Maxim N↗
DOE OSTI2016

Long-Term Efficacy of Percutaneous Internal Plastic Stent Placement for Non-anastomotic Biliary Stenosis After Liver Transplantation

PurposeWe aimed to evaluate the long-term efficacy of percutaneous management of non-anastomotic biliary stenosis after liver transplantation, using plastic internal biliary stents.Materials and MethodsThis study included 35 cases (28 men, 7 women; mean age: 52.09 ± 8.13 years, range 34–68) in 33 patients who needed repeated interventional procedures because of biliary strictures. After classification of the biliary strictures, we inserted percutaneous biliary plastic stents through the T-tube or percutaneous transhepatic biliary drainage tracts. Stents were exchanged according to percutaneous methods at regular 2- to 6-month intervals. The stents were removed if the condition improved, as observed on cholangiogram as well as based on clinical findings. The median patient follow-up period after initial diagnosis and treatment was 6.04 years (range 0.29–9.95 years). We assessed treatment success rate and patient and graft survival times.ResultsDuring the follow-up period, 14 patients (14/33, 42.42 %) were successfully treated and were tube-free. The median tube-free time, time without a stent, was 4.13 years (range 1.00–9.01). In contrast, internal plastic stents remained in 9 patients (9/33, 27.27 %) until the last follow-up. These patients had acceptable hepatic function. Among the remaining 10 patients, 3 (3/33, 9.09 %) were lost to regular follow-up and the other 7 (7/33, 21.21 %) patients died. The overall graft loss rate was 20.0 % (7/35). The median time from initial treatment to graft loss was 1.84 years (range 0.42–4.25).ConclusionsPercutaneous plastic stents placement is technically feasible and clinically useful in patients with multiple biliary stenoses following liver transplantation.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2024

Plasticity-mediated deformation instabilities in thin film-compliant substrate systems: direct three-dimensional simulations

Abstract Surface wrinkles driven by mechanical instability commonly form in thin-film structures attached to a compliant substrate. In this study, a recently developed computational approach is employed to simulate the formation and transformation of wrinkles involving plastic yielding of the thin film. The three-dimensional (3D) finite element models contain an embedded imperfection at the film-substrate interface, serving to trigger the bifurcation modes. Successful application of this technique to allow for film plasticity is demonstrated, including the evolution of 3D surface patterns and their correlation with the overall load–displacement response. The simulations reveal that plastic yielding transforms the surface instability patterns into more localized forms. Under uniaxial loading, the sinusoidal elastic wrinkles undergo the wrinkle-to-fold transition. With equi-biaxial loading, the initial square-checkerboard array turns into continuous tall ridges along the 45° directions. In both loading modes, the plasticity-induced instability patterns are only partially relieved upon unloading, leaving permanent features on the surface.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Ion Implantation-Induced Plastic Phenomena in Metallic Alloys

Ion implantation is widely used for doping semiconductors or electroceramic materials and probing material behaviors in extreme radiation environments. However, implanted ions can induce compressive stresses into the host material, which can induce plasticity and mesoscopic deformation. However, these phenomena have almost exclusively been observed in brittle ionic and/or covalently bonded materials. Here, in this study, we present transmission electron microscopy observations of unusual implantation-induced plasticity in two metallic alloys. First, Fe 2+ ions induce dislocation plasticity below the implanted layer in a model Fe-P alloy. Next, He+ ions form pressurized cavities which activate the fcc-to-hcp strain-induced martensitic transformation in Alloy 625. In both cases, the plasticity can be explained by a combination of implanted ions being incorporated into the lattice and the creation of irradiation defects. These findings have significant implications for mechanical testing of ion-implanted layers, while also opening pathways for using ion implantation to tune stress distributions in metallic alloys.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Machine Learning–Based Reduce Order Crystal Plasticity Modeling for ICME Applications

Abstract Crystal plasticity simulation is a widely used technique for studying the deformation processing of polycrystalline materials. However, inclusion of crystal plasticity simulation into design paradigms such as integrated computational materials engineering (ICME) is hindered by the computational cost of large-scale simulations. In this work, we present a machine learning (ML) framework using the material information platform, Open Citrination, to develop and calibrate a reduced order crystal plasticity model for face-centered cubic (FCC) polycrystalline materials, which can be both rapidly exercised and easily inverted. The reduced order model takes crystallographic texture, constitutive model parameters, and loading condition as inputs and returns the stress-strain curve and final texture. The model can also be inverted and take a stress-strain curve, loading condition, and final texture as inputs and return the initial texture and constitutive model parameters as outputs. Principal component analysis (PCA) is used to develop an efficient description of the crystallographic texture. A viscoplastic self-consistent (VPSC) crystal plasticity solver is used to create the training data by modeling the stress-strain behavior and evolution of texture during deformation processing.

Yuan, Mengfei↗
DOE OSTI2025

Structure-dependent mechanisms for plastic degradation in the marine environment

The visible and invisible accumulation of waste plastic in our oceans is a consequence of rapidly increasing inputs and very slow degradation rates. In general, this combination of effects results in long residence times. Nevertheless, the abiological degradation rate of a specific synthetic plastic varies widely, depending on its structural characteristics at the molecular, mesoscopic, and macroscopic levels. This chapter summarizes factors that determine these rates of degradation, and describes their principal mechanisms, for several of the major types of waste plastic found in the oceans. Mechanical forces cause cracking and flaking that break macroplastics into microplastics and even smaller fragments with increasing surface-to-volume ratios. Chemical degradation rates increase with surface area, influenced by intrinsic variations in crystallinity and the presence of additives, as well as extrinsic factors such as temperature, pH, and UV light intensity. Since polyolefin-based plastics are less dense than seawater and lack hydrolysable bonds in their polymer backbones, they accumulate close to the surface of the ocean where photo-oxidation is the principal cause of C–C bond cleavage in the polymer backbone. In contrast, polyesters and polyamides are denser than seawater and they sink, experiencing less exposure to solar irradiation. However, they can also degrade by slow hydrolysis of the C–O or C–N bonds intrinsic to the polymer structures.

Maciulis, Nicholas A.↗
DOE OSTI2025

Electrocatalytic grafting of polyvinyl chloride plastics

Polyvinyl chloride (PVC) plastics require high loadings of plasticizers and stabilizers to achieve commercially useful bulk properties. However, these non-covalent additives leach from PVC over time, resulting in the loss of their tailored functionality. This work details the electrocatalytic functionalization of PVC to covalently graft plasticizing additives directly onto the polymer backbone. Here, mechanistic insights guided the design of electrocatalysts capable of modifying C–Cl bonds of PVC under mild conditions with high selectivity while suppressing side reactions such as elimination and chain scission. Functional groups that mimic PVC plasticizers are covalently installed into the backbone of PVC to create new materials with distinct bulk properties from the original polymer. The degree of polymer grafting is easily controlled by simply changing the redox capacity that is passed during electrolysis. This strategy is employed to create chemically- and leach-resistant PVC materials by directly electrolyzing mixtures of consumer PVC products

Zackasee, Jordan L.S.↗
DOE OSTI2018

Hydraulic anatomy affects genotypic variation in plant water use and shows differential organ specific plasticity to drought in Sorghum bicolor

Genotypic variability and plasticity in hydraulic anatomy are not well-understood in herbaceous monocots. In this work, we used Sorghum bicolor , a monocotyledonous, tropical grass model, to understand whether differential plant water use is associated with xylem anatomy and if whole-plant xylem anatomy responds to water stress, justifying differential genotypic sensitivity to drought. In a greenhouse environment, we studied four sorghum genotypes that are known to genetically differ in growth and exhibit differential sensitivity to drought. Under well-watered scenario, transpiration variability and plant growth traits correlated with xylem anatomical traits at both the leaf and stem level, including xylem area and predicted xylem-specific hydraulic conductivity. High water use genotypes had inherently higher hydraulic capacity, but under drought, their transpiration declined at higher fractions of transpirable soil water ( FTSW ) and they showed greater plasticity in hydraulic anatomy. However, lower FTSW thresholds and modest anatomical changes were identified in the low water use genotypes with inherently lower hydraulic conductivity. Drought, induced modular phenotypic plasticity in hydraulic anatomy, whereby plasticity in leaf xylem traits was remarkably higher than stem xylem, while root xylem showed a reverse nature of vascular modification. Xylem traits were in agreement with phloem anatomy, irrespective of water regime. In conclusion, our study indicates that hydraulic anatomy can be critical for herbaceous monocots in determining limits to plant water use and genotypic response to drought with implications on whole-plant functions and habitat ecology.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2017

A crystal plasticity model incorporating the effects of precipitates in superalloys: Application to tensile, compressive, and cyclic deformation of Inconel 718

An elasto-plastic polycrystal plasticity model is developed and applied to an Inconel 718 (IN718) superalloy that was produced by additive manufacturing (AM). The model takes into account the contributions of solid solution, precipitates shearing, and grain size and shape effects into the initial slip resistance. Non-Schmid effects and backstress are also included in the crystal plasticity model for activating slip. The hardening law for the critical resolved shear stress is based on the evolution of dislocation density. In using the same set of material and physical parameters, the model is compared against a suite of compression, tension, and large-strain cyclic mechanical test data applied in different AM build directions. We demonstrate that the model is capable of predicting the particularities of both monotonic and cyclic deformation to large strains of the alloy, including decreasing hardening rate during monotonic loading, the non-linear unloading upon the load reversal, the Bauschinger effect, the hardening rate change during loading in the reverse direction as well as plastic anisotropy and the concomitant microstructure evolution. It is anticipated that the general model developed here can be applied to other multiphase alloys containing precipitates.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Examining deformation localization of irradiated tungsten under uniaxial compression with crystal plasticity

In this work, the deformation behavior of irradiated tungsten at elevated service temperatures is examined using mechanism-based crystal plasticity finite element framework by considering multiple mechanisms, including thermal softening and irradiation hardening. The previously developed mechanism-based crystal plasticity model is first utilized to assess the yield stress of unirradiated and irradiated tungsten upon low-temperature irradiation. Additionally, the engineering stress-strain response under uniaxial compression is then predicted by considering the effect of irradiation-induced defect clusters on the motion of deformation-induced dislocations, and the predicted results agree well with the experimental measurements. More importantly, the formation and evolution of plastic strain localization zones in the form of shear bands are qualitatively captured, and the maximal principal strain distribution is quantitatively linked to the dose of irradiation damage. Finally, the deformation-induced shear band as a result of plastic instability in the compressed tungsten specimen is discussed.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Strain localization and elastic-plastic coupling during deformation of porous sandstone

In this paper, results of axisymmetric compression tests on weak, porous Castlegate Sandstone (Cretaceous, Utah, USA), covering a range of dilational and compactional behaviors, are examined for localization behavior. Assuming isotropy, bulk and shear moduli evolve as increasing functions of mean stress and Mises equivalent shear stress respectively, and as decreasing functions of work-conjugate plastic strains. Acoustic emissions events located during testing show onset of localization and permit calculation of observed shear and low-angle compaction localization zones, or bands, as localization commences. Total strain measured experimentally partitions into: A) elastic strain with constant moduli, B) elastic strain due to stress dependence of moduli, C) elastic strain due to moduli degradation with increasing plastic strain, and D) plastic strain. The third term is the elastic-plastic coupling strain, and though often ignored, contributes significantly to pre-failure total strain for brittle and transitional tests. Constitutive parameters and localization predictions derived from experiments are compared to theoretical predictions. In the brittle regime, predictions of band angles (angle between band normal and maximum compression) demonstrate good agreement with observed shear band angles. Compaction localization was observed in the transitional regime in between shear localization and spatially pervasive compaction, over a small range of mean stresses. Finally, in contrast with predictions, detailed acoustic emissions analyses in this regime show low angle, compaction-dominated but shear-enhanced, localization.

15 GEOTHERMAL ENERGY↗