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Low Cost, Durable Seal

Description: Seal durability is critical to achieving the 2010 DOE operational life goals for both stationary and transportation PEM fuel cell stacks. The seal material must be chemically and mechanically stable in an environment consisting of aggressive operating temperatures, humidified gases, and acidic membranes. The seal must also be producible at low cost. Currentlyused seal materials do not meet all these requirements. This project developed and demonstrated a high consistency hydrocarbon rubber seal material that was able to meet the DOE technical and cost targets. Significant emphasis was placed on characterization of the material and full scale molding demonstrations.
Date: December 17, 2010
Creator: Roberts, George; Parsons, Jason & Friedman, Jake
Partner: UNT Libraries Government Documents Department

Nuclear Magnetic Resonance Imaging of Green-State Ceramics

Description: Proton (¹H) nuclear magnetic resonance (NMR) imaging techniques are investigated as a means to nondestructively characterize green-state (unfired) Si{sub 3}N{sub 4} ceramic components. Spectroscopic results indicate that the organic additives used in the injection molding of ceramics behave as soft solids, with broad spectral peak widths (T₂ <0.5 ms) and moderate multicomponent spin-lattice relaxation rates (T{sub 1} ranging from 11 ms to 1 s). Because of the intrinsically different spectral characteristics of the organic additives, conventional-solution NMR imaging techniques cannot be applied to these materials. Hence, the authors developed specialized NMR imaging accessories capable of applying high magnetic field gradients in a back-projection protocol. NMR images were acquired of injection-molded test bars that had been fabricated with different mixing and molding parameters. Organic concentrations determined from the NMR images were correlated with results obtained through destructive testing. The correlation suggests that NMR imaging is a viable technique for quantifying organics in injection-molded green-state ceramics.
Date: August 1990
Creator: Gopalsami, Nachappa; Dieckman, S. L.; Ellingson, W. A.; Botto, Robert E.; Wong, P. S.; Yeh, H. C. et al.
Partner: UNT Libraries Government Documents Department

Predictive Engineering Tools for Injection-Molded Long-Carbon-Fiber Thermoplastic Composites - Quarterly Report

Description: This quarterly report summarizes the status for the project planning to initiate all the legal and contract documents required for establishing the subcontracts needed and a Cooperative Research and Development Agreement (CRADA) with Autodesk, Inc., Toyota Motor Engineering and Manufacturing North America (Toyota), and Magna Exterior and Interiors Corporation (Magna). During the first quarter (10/1/2012 to 12/31/2012), the statements of work (SOW) for the subcontracts to Purdue University, University of Illinois, and PlastiComp, Inc. were completed. A draft of the CRADA SOW was sent to Autodesk, Toyota, and Magna for technical and legal reviews. PNNL Legal Services contacted project partners’ Legal counterparts for preparing legal documents for the project. A non-disclosure agreement was drafted and sent to all the parties for reviews.
Date: April 4, 2013
Creator: Nguyen, Ba Nghiep & Simmons, Kevin L.
Partner: UNT Libraries Government Documents Department

Predictive Engineering Tools for Injection-Molded Long-Carbon-Fiber Thermoplastic Composites - FY13 Third Quarterly Report

Description: This quarterly report summarizes the status for the project planning to obtain all the approvals required for a Cooperative Research and Development Agreement (CRADA) with Autodesk, Inc., Toyota Motor Engineering and Manufacturing North America (Toyota), and Magna Exterior and Interiors Corporation (Magna). The CRADA documents have been processed by PNNL Legal Services that is also coordinating the revision effort with the industrial parties to address DOE’s comments.
Date: August 6, 2013
Creator: Nguyen, Ba Nghiep & Simmons, Kevin L.
Partner: UNT Libraries Government Documents Department

Predictive Engineering Tools for Injection-Molded Long-Carbon-Fiber Thermoplastic Composites - FY13 Fourth Quarterly Report

Description: This quarterly report summarizes the status of the project planning to obtain all the approvals required for a Cooperative Research and Development Agreement (CRADA) with Autodesk, Inc., Toyota Motor Engineering and Manufacturing North America (Toyota), and Magna Exterior and Interiors Corporation (Magna). The final CRADA documents processed by PNNL’s Legal Services were submitted to all the parties for signatures.
Date: December 2, 2013
Creator: Nguyen, Ba Nghiep & Simmons, Kevin L.
Partner: UNT Libraries Government Documents Department

Predictive Engineering Tools for Injection-Molded Long-Carbon-Fiber Thermoplastic Composites

Description: This quarterly report summarizes the status for the project planning to complete all the legal and contract documents required for establishing the subcontracts needed and a Cooperative Research and Development Agreement (CRADA) with Autodesk, Inc., Toyota Motor Engineering and Manufacturing North America (Toyota), and Magna Exterior and Interiors Corporation (Magna). During the second quarter (1/1/2013 to 3/31/2013), all the technical and legal documents for the subcontracts to Purdue University, University of Illinois, and PlastiComp, Inc. were completed. The revised CRADA documents were sent to DOE, Autodesk, Toyota, and Magna for technical and legal reviews. PNNL Legal Services contacted project partners’ Legal counterparts for completing legal documents for the project. A non-disclosure agreement was revised and sent to all the parties for reviews.
Date: May 30, 2013
Creator: Nguyen, Ba Nghiep & Simmons, Kevin L.
Partner: UNT Libraries Government Documents Department

Assessment of Current Process Modeling Approaches to Determine Their Limitations, Applicability and Developments Needed for Long-Fiber Thermoplastic Injection Molded Composites

Description: This report describes the status of the current process modeling approaches to predict the behavior and flow of fiber-filled thermoplastics under injection molding conditions. Previously, models have been developed to simulate the injection molding of short-fiber thermoplastics, and an as-formed composite part or component can then be predicted that contains a microstructure resulting from the constituents’ material properties and characteristics as well as the processing parameters. Our objective is to assess these models in order to determine their capabilities and limitations, and the developments needed for long-fiber injection-molded thermoplastics (LFTs). First, the concentration regimes are summarized to facilitate the understanding of different types of fiber-fiber interaction that can occur for a given fiber volume fraction. After the formulation of the fiber suspension flow problem and the simplification leading to the Hele-Shaw approach, the interaction mechanisms are discussed. Next, the establishment of the rheological constitutive equation is presented that reflects the coupled flow/orientation nature. The decoupled flow/orientation approach is also discussed which constitutes a good simplification for many applications involving flows in thin cavities. Finally, before outlining the necessary developments for LFTs, some applications of the current orientation model and the so-called modified Folgar-Tucker model are illustrated through the fiber orientation predictions for selected LFT samples.
Date: November 30, 2006
Creator: Nguyen, Ba Nghiep; Holbery, Jim; Smith, Mark T.; Kunc, Vlastimil; Norris, Robert E.; Phelps, Jay et al.
Partner: UNT Libraries Government Documents Department

Validation of New Process Models for Large Injection-Molded Long-Fiber Thermoplastic Composite Structures

Description: This report describes the work conducted under the CRADA Nr. PNNL/304 between Battelle PNNL and Autodesk whose objective is to validate the new process models developed under the previous CRADA for large injection-molded LFT composite structures. To this end, the ARD-RSC and fiber length attrition models implemented in the 2013 research version of Moldflow was used to simulate the injection molding of 600-mm x 600-mm x 3-mm plaques from 40% glass/polypropylene (Dow Chemical DLGF9411.00) and 40% glass/polyamide 6,6 (DuPont Zytel 75LG40HSL BK031) materials. The injection molding was performed by Injection Technologies, Inc. at Windsor, Ontario (under a subcontract by Oak Ridge National Laboratory, ORNL) using the mold offered by the Automotive Composite Consortium (ACC). Two fill speeds under the same back pressure were used to produce plaques under slow-fill and fast-fill conditions. Also, two gating options were used to achieve the following desired flow patterns: flows in edge-gated plaques and in center-gated plaques. After molding, ORNL performed measurements of fiber orientation and length distributions for process model validations. The structure of this report is as follows. After the Introduction (Section 1), Section 2 provides a summary of the ARD-RSC and fiber length attrition models. A summary of model implementations in the latest research version of Moldflow is given in Section 3. Section 4 provides the key processing conditions and parameters for molding of the ACC plaques. The validations of the ARD-RSC and fiber length attrition models are presented and discussed in Section 5. The conclusions will be drawn in Section 6.
Date: February 23, 2012
Creator: Nguyen, Ba Nghiep; Jin, Xiaoshi; Wang, Jin; Kunc, Vlastimil & Tucker III, Charles L.
Partner: UNT Libraries Government Documents Department

Mechanical behavior and performance of injection molded semi-crystalline polymers.

Description: I have used computer simulations to investigate the behavior of polymeric materials at the molecular level. The simulations were performed using the molecular dynamics method with Lennard-Jones potentials defining the interactions between particles in the system. Significant effort was put into the creation of realistic materials on the computer. For this purpose, an algorithm was developed based on the step-wise polymerization process. The resulting computer-generated materials (CGMs) exhibit several features of real materials, such as molecular weight distribution and presence of chain entanglements. The effect of the addition of a liquid crystalline (LC) phase to the flexible matrix was also studied. The concentration and distribution of the second phase (2P) were found to influence the mechanical and tribological properties of the CGMs. The size of the 2P agglomerates was found to have negligible influence on the properties within the studied range. Moreover, although the 2P reinforcement increases the modulus, it favors crack formation and propagation. Regions of high LC concentration exhibit high probability of becoming part of the crack propagation path. Simulations of the tensile deformation under a uniaxial force have shown that the molecular deformation mechanisms developing in the material depend on several variables, such as the magnitude of the force, the force increase rate, and the level of orientation of the chains. Three-dimensional (3D) graphical visualization tools were developed for representation and analysis of the simulation results. These also present interesting educational possibilities. Computer simulations provide us information which is inaccessible experimentally. From the concomitant use of simulations and experiments, a better understanding of the molecular phenomena that take place during deformation of polymers has been established.
Access: This item is restricted to the UNT Community Members at a UNT Libraries Location.
Date: August 2003
Creator: Simoes, Ricardo J. F.
Partner: UNT Libraries

PNNL Technical Support to The Implementation of EMTA and EMTA-NLA Models in Autodesk® Moldflow® Packages

Description: Under the Predictive Engineering effort, PNNL developed linear and nonlinear property prediction models for long-fiber thermoplastics (LFTs). These models were implemented in PNNL’s EMTA and EMTA-NLA codes. While EMTA is a standalone software for the computation of the composites thermoelastic properties, EMTA-NLA presents a series of nonlinear models implemented in ABAQUS® via user subroutines for structural analyses. In all these models, it is assumed that the fibers are linear elastic while the matrix material can exhibit a linear or typical nonlinear behavior depending on the loading prescribed to the composite. The key idea is to model the constitutive behavior of the matrix material and then to use an Eshelby-Mori-Tanaka approach (EMTA) combined with numerical techniques for fiber length and orientation distributions to determine the behavior of the as-formed composite. The basic property prediction models of EMTA and EMTA-NLA have been subject for implementation in the Autodesk® Moldflow® software packages. These models are the elastic stiffness model accounting for fiber length and orientation distributions, the fiber/matrix interface debonding model, and the elastic-plastic models. The PNNL elastic-plastic models for LFTs describes the composite nonlinear stress-strain response up to failure by an elastic-plastic formulation associated with either a micromechanical criterion to predict failure or a continuum damage mechanics formulation coupling damage to plasticity. All the models account for fiber length and orientation distributions as well as fiber/matrix debonding that can occur at any stage of loading. In an effort to transfer the technologies developed under the Predictive Engineering project to the American automotive and plastics industries, PNNL has obtained the approval of the DOE Office of Vehicle Technologies to provide Autodesk, Inc. with the technical support for the implementation of the basic property prediction models of EMTA and EMTA-NLA in the Autodesk® Moldflow® packages. This report summarizes the recent results from Autodesk Simulation ...
Date: December 1, 2012
Creator: Nguyen, Ba Nghiep & Wang, Jin
Partner: UNT Libraries Government Documents Department

Metalcasting: Die Casting Copper Motor Rotors

Description: Decreased energy requirements, air emissions, production time, and operating costs are some of the benefits that will accrue to the metalcasting industry as result of this new die casting technique. This fact sheet provides the details of this exciting new process for fabricating copper motor rotors.
Date: January 29, 1999
Creator: Recca, L.
Partner: UNT Libraries Government Documents Department

EMTA’s Evaluation of the Elastic Properties for Fiber Polymer Composites Potentially Used in Hydropower Systems

Description: Fiber-reinforced polymer composites can offer important advantages over metals where lightweight, cost-effective manufacturing and high mechanical performance can be achieved. To date, these materials have not been used in hydropower systems. In view of the possibility to tailor their mechanical properties to specific applications, they now have become a subject of research for potential use in hydropower systems. The first step in any structural design that uses composite materials consists of evaluating the basic composite mechanical properties as a function of the as-formed composite microstructure. These basic properties are the elastic stiffness, stress-strain response, and strength. This report describes the evaluation of the elastic stiffness for a series of common discontinuous fiber polymer composites processed by injection molding and compression molding in order to preliminarily estimate whether these composites could be used in hydropower systems for load-carrying components such as turbine blades. To this end, the EMTA (Copyright © Battelle 2010) predictive modeling tool developed at the Pacific Northwest National Laboratory (PNNL) has been applied to predict the elastic properties of these composites as a function of three key microstructural parameters: fiber volume fraction, fiber orientation distribution, and fiber length distribution. These parameters strongly control the composite mechanical performance and can be tailored to achieve property enhancement. EMTA uses the standard and enhanced Mori-Tanaka type models combined with the Eshelby equivalent inclusion method to predict the thermoelastic properties of the composite based on its microstructure.
Date: August 1, 2010
Creator: Nguyen, Ba Nghiep & Paquette, Joshua
Partner: UNT Libraries Government Documents Department

Modeling injection molding of net-shape active ceramic components.

Description: To reduce costs and hazardous wastes associated with the production of lead-based active ceramic components, an injection molding process is being investigated to replace the current machining process. Here, lead zirconate titanate (PZT) ceramic particles are suspended in a thermoplastic resin and are injected into a mold and allowed to cool. The part is then bisque fired and sintered to complete the densification process. To help design this new process we use a finite element model to describe the injection molding of the ceramic paste. Flow solutions are obtained using a coupled, finite-element based, Newton-Raphson numerical method based on the GOMA/ARIA suite of Sandia flow solvers. The evolution of the free surface is solved with an advanced level set algorithm. This approach incorporates novel methods for representing surface tension and wetting forces that affect the evolution of the free surface. Thermal, rheological, and wetting properties of the PZT paste are measured for use as input to the model. The viscosity of the PZT is highly dependent both on temperature and shear rate. One challenge in modeling the injection process is coming up with appropriate constitutive equations that capture relevant phenomenology without being too computationally complex. For this reason we model the material as a Carreau fluid and a WLF temperature dependence. Two-dimensional (2D) modeling is performed to explore the effects of the shear in isothermal conditions. Results indicate that very low viscosity regions exist near walls and that these results look similar in terms of meniscus shape and fill times to a simple Newtonian constitutive equation at the shear-thinned viscosity for the paste. These results allow us to pick a representative viscosity to use in fully three-dimensional (3D) simulation, which because of numerical complexities are restricted to using a Newtonian constitutive equation. Further 2D modeling at nonisothermal conditions shows that ...
Date: November 1, 2006
Creator: Baer, Tomas (Gram Inc.); Cote, Raymond O.; Grillet, Anne Mary; Yang, Pin; Hopkins, Matthew Morgan; Noble, David R. et al.
Partner: UNT Libraries Government Documents Department

Low Speed Technology for Small Turbine Development Reaction Injection Molded 7.5 Meter Wind Turbine Blade

Description: An optimized small turbine blade (7.5m radius) was designed and a partial section molded with the RIM (reaction-injection molded polymer) process for mass production. The intended market is for generic three-bladed wind turbines, 100 kilowatts or less, for grid-assist end users with rural and semi-rural sites, such as the farm/ranch market, having low to moderate IEC Class 3-4 wind regimes. This blade will have substantial performance improvements over, and be cheaper than, present-day 7.5m blades. This is made possible by the injection-molding process, which yields high repeatability, accurate geometry and weights, and low cost in production quantities. No wind turbine blade in the 7.5m or greater size has used this process. The blade design chosen uses a RIM skin bonded to a braided infused carbon fiber/epoxy spar. This approach is attractive to present users of wind turbine blades in the 5-10m sizes. These include rebladeing California wind farms, refurbishing used turbines for the Midwest farm market, and other manufacturers introducing new turbines in this size range.
Date: July 31, 2007
Creator: Wright, David M. & Bennett, DOE Project Officer - Keith
Partner: UNT Libraries Government Documents Department