13 Matching Results

Search Results

Advanced search parameters have been applied.

FY04 Engineering Technology Reports Technology Base

Description: Lawrence Livermore National Laboratory's Engineering Directorate has two primary discretionary avenues for its investment in technologies: the Laboratory Directed Research and Development (LDRD) program and the ''Tech Base'' program. This volume summarizes progress on the projects funded for technology-base efforts in FY2004. The Engineering Technical Reports exemplify Engineering's more than 50-year history of researching and developing (LDRD), and reducing to practice (technology-base) the engineering technologies needed to support the Laboratory's missions. Engineering has been a partner in every major program and project at the Laboratory throughout its existence, and has prepared for this role with a skilled workforce and technical resources. This accomplishment is well summarized by Engineering's mission: ''Enable program success today and ensure the Laboratory's vitality tomorrow''. LDRD is the vehicle for creating those technologies and competencies that are cutting edge. These require a significant level of research or contain some unknown that needs to be fully understood. Tech Base is used to apply those technologies, or adapt them to a Laboratory need. The term commonly used for Tech Base projects is ''reduction to practice''. Tech Base projects effect the natural transition to reduction-to-practice of scientific or engineering methods that are well understood and established. They represent discipline-oriented, core competency activities that are multi-programmatic in application, nature, and scope. The objectives of technology-base funding include: (1) the development and enhancement of tools and processes to provide Engineering support capability, such as code maintenance and improved fabrication methods; (2) support of Engineering science and technology infrastructure, such as the installation or integration of a new capability; (3) support for technical and administrative leadership through our technology Centers; and (4) the initial scoping and exploration of selected technology areas with high strategic potential, such as assessment of university, laboratory, and industrial partnerships. Engineering's five Centers, in partnership with the Division ...
Date: January 27, 2005
Creator: Sharpe, R M
Partner: UNT Libraries Government Documents Department

FY04 Engineering Technology Reports Laboratory Directed Research and Development

Description: This report summarizes the science and technology research and development efforts in Lawrence Livermore National Laboratory's Engineering Directorate for FY2004, and exemplifies Engineering's more than 50-year history of developing the technologies needed to support the Laboratory's missions. Engineering has been a partner in every major program and project at the Laboratory throughout its existence and has prepared for this role with a skilled workforce and the technical resources developed through venues like the Laboratory Directed Research and Development Program (LDRD). This accomplishment is well summarized by Engineering's mission: ''Enable program success today and ensure the Laboratory's vitality tomorrow''. Engineering's investment in technologies is carried out through two programs, the ''Tech Base'' program and the LDRD program. LDRD is the vehicle for creating those technologies and competencies that are cutting edge. These require a significant level of research or contain some unknown that needs to be fully understood. Tech Base is used to apply technologies to a Laboratory need. The term commonly used for Tech Base projects is ''reduction to practice''. Therefore, the LDRD report covered here has a strong research emphasis. Areas that are presented all fall into those needed to accomplish our mission. For FY2004, Engineering's LDRD projects were focused on mesoscale target fabrication and characterization, development of engineering computational capability, material studies and modeling, remote sensing and communications, and microtechnology and nanotechnology for national security applications. Engineering's five Centers, in partnership with the Division Leaders and Department Heads, are responsible for guiding the long-term science and technology investments for the Directorate. The Centers represent technologies that have been identified as critical for the present and future work of the Laboratory, and are chartered to develop their respective areas. Their LDRD projects are the key resources to attain this competency, and, as such, nearly all of Engineering's portfolio falls ...
Date: January 27, 2005
Creator: Sharpe, R M
Partner: UNT Libraries Government Documents Department

Electromagnetic interactions GEneRalized (EIGER): algorithm abstraction and HPC implementation

Description: Modern software development methods combined with key generalizations of standard computational algorithms enable the development of a new class of electromagnetic modeling tools. This paper describes current and anticipated capabilities of a frequency domain modeling code, EIGER, which has an extremely wide range of applicability. In addition, software implementation methods and high performance computing issues are discussed.
Date: April 21, 1998
Creator: Sharpe, R.M., LLNL
Partner: UNT Libraries Government Documents Department

Numerical Modeling of Left-Handed Metamaterials

Description: The EIGER method of moments program with periodic Green's function was used to model a periodic array of strips and split-ring resonators. Left-handed propagation due to negative index of refraction is demonstrated in a frequency band. The effective material parameters versus frequency are extracted from the EIGER solution.
Date: November 6, 2001
Creator: Burke, G J; Champagne, N J & Sharpe, R M
Partner: UNT Libraries Government Documents Department

EIGER: Electromagnetic Interactions GEneRalized

Description: The EIGER (Electromagnetic Interactions Generalized) modeling suite is a joint development activity by the Lawrence Livermore National Lab, Sandia National Labs, the University of Houston, and the Navy (Space and Naval Warfare Systems Center-San Diego). The effort endeavors to bring the next generation of hybrid, higher-order, full-wave analysis methods into a single integrated framework. The tools are based upon frequency-domain solutions of Maxwell's equations to model scattering and radiation from complex 2D and 3D structures. The framework employs boundary element solutions of integral equation formulations and finite element solutions of the Helmholtz wave equation. A goal is to use higher-order representations to model both the geometry (using higher-order geometric elements) and numerical methods (using higher-order vector basis functions). In addition, a variety of advanced Green's functions and symmetry operators can be applied to efficiently treat geometries containing such features as layered material regions and periodic structures. Each of these methods can be brought to bear simultaneously, on different portions of a complex structure. HPC implementation issues were addressed during the design of the software architecture, so that the same package runs on platforms ranging from serial desktop workstations through advanced HPC architectures. Our current efforts on higher-order modeling and improved solver libraries will be highlighted.
Date: June 13, 2001
Creator: Champagne, N J; Sharpe, R M & Rockway, J W
Partner: UNT Libraries Government Documents Department

A Generalized Fast Frequency Sweep Algorithm for Coupled Circuit-EM Simulations

Description: Frequency domain techniques are popular for analyzing electromagnetics (EM) and coupled circuit-EM problems. These techniques, such as the method of moments (MoM) and the finite element method (FEM), are used to determine the response of the EM portion of the problem at a single frequency. Since only one frequency is solved at a time, it may take a long time to calculate the parameters for wideband devices. In this paper, a fast frequency sweep based on the Asymptotic Wave Expansion (AWE) method is developed and applied to generalized mixed circuit-EM problems. The AWE method, which was originally developed for lumped-load circuit simulations, has recently been shown to be effective at quasi-static and low frequency full-wave simulations. Here it is applied to a full-wave MoM solver, capable of solving for metals, dielectrics, and coupled circuit-EM problems.
Date: January 14, 2004
Creator: Rockway, J D; Champagne, N J; Sharpe, R M & Fasenfest, B
Partner: UNT Libraries Government Documents Department

EIGER: A new generation of computational electromagnetics tools

Description: The EIGER project (Electromagnetic Interactions GenERalized) endeavors to bring the next generation of spectral domain electromagnetic analysis tools to maturity and to cast them in a general form which is amenable to a variety of applications. The tools are written in Fortran 90 and with an object oriented philosophy to yield a package that is easily ported to a variety of platforms, simply maintained, and above all efficiently modified to address wide ranging applications. The modular development style and the choice of Fortran 90 is also driven by the desire to run efficiently on existing high performance computer platforms and to remain flexible for new architectures that are anticipated. The electromagnetic tool box consists of extremely accurate physics models for 2D and 3D electromagnetic scattering, radiation, and penetration problems. The models include surface and volume formulations for conductors and complex materials. In addition, realistic excitations and symmetries are incorporated, as well as, complex environments through the use of Green`s functions.
Date: March 1996
Creator: Wilton, D. R.; Johnson, W. A.; Jorgenson, R. E.; Sharpe, R. M. & Grant, J. B.
Partner: UNT Libraries Government Documents Department

EIGER: Electromagnetic Interactions GEneRalized

Description: EIGER (Electromagnetic Interactions GEneRalized), a single integrated software tool set, brings together a variety of spectral domain analysis methods. These include moment method solutions of integral equation formulations and finite elements solutions of partial differential equations. New software engineering methods, specifically, object oriented design, are being used to implement abstractions of key components of spectral analysis methods so that the tools can be easily modified and extended to treat new classes of problems. The key components of the numerical analysis tool, and their roles, are: elements - to describe the geometry, basis (expansion) functions - to interpolate the unknowns (e.g., fields) locally, and operators - to express the underlying physics formulations used to propagate the energy or enforce fundamental principals. The development of EMPACK provided the fundamental impetus for these abstractions which are discussed more fully in subsequent sections. This design approach is in contrast to standard design procedures where entire codes are developed around a particular element type with a specific basis function for a single operator. Although such tools can be effectively used to model large classes of problems, it is often very difficult, if not intractable, to extend the tools beyond their initial design. Overcoming this limitation is one of the most compelling goals of this project. We have successfully overcome roadblocks encountered in extension of past development efforts, such as the extension of Patch to treat wires and wire-surface junctions in the presence of non-homogeneous media. Moreover, the application base for EIGER grows as we cast a variety of Green`s functions into a form compatible with the numerical procedures in EIGER.
Date: March 1, 1997
Creator: Sharpe, R. M.; Grant, J. B. & Champagne, N. J.
Partner: UNT Libraries Government Documents Department

A finite-difference frequency-domain code for electromagnetic induction tomography

Description: We are developing a new 3D code for application to electromagnetic induction tomography and applications to environmental imaging problems. We have used the finite-difference frequency- domain formulation of Beilenhoff et al. (1992) and the anisotropic PML (perfectly matched layer) approach (Berenger, 1994) to specify boundary conditions following Wu et al. (1997). PML deals with the fact that the computations must be done in a finite domain even though the real problem is effectively of infinite extent. The resulting formulas for the forward solver reduce to a problem of the form Ax = y, where A is a non-Hermitian matrix with real values off the diagonal and complex values along its diagonal. The matrix A may be either symmetric or nonsymmetric depending on details of the boundary conditions chosen (i.e., the particular PML used in the application). The basic equation must be solved for the vector x (which represents field quantities such as electric and magnetic fields) with the vector y determined by the boundary conditions and transmitter location. Of the many forward solvers that could be used for this system, relatively few have been thoroughly tested for the type of matrix encountered in our problem. Our studies of the stability characteristics of the Bi-CG algorithm raised questions about its reliability and uniform accuracy for this application. We have found the stability characteristics of Bi-CGSTAB [an alternative developed by van der Vorst (1992) for such problems] to be entirely adequate for our application, whereas the standard Bi-CG was quite inadequate. We have also done extensive validation of our code using semianalytical results as well as other codes. The new code is written in Fortran and is designed to be easily parallelized, but we have not yet tested this feature of the code. An adjoint method is being developed for solving the ...
Date: December 17, 1998
Creator: Sharpe, R M; Berryman, J G; Buettner, H M; Champagne, N J.,II & Grant, J B
Partner: UNT Libraries Government Documents Department

A methodology for assessing high intensity RF effects in aircraft

Description: Optical components have an inherent immunity to the electromagnetic interference (EMI) associated with High Intensity Radiated Fields (HIRF). The optical technology embodied in Fly-by-Light (FBL) might therefore minimize the effects of HIRF on digitally controlled systems while providing lifetime immunity to signal EMI. This is one of the primary motivations for developing FBL systems for aircraft. FBL has the potential to greatly simplify EMI certification by enabling technically acceptable laboratory tests of subsystems, as opposed to expensive full airplane tests. In this paper the authors describe a methodology for assessing EMI effects on FBL aircraft that reduces or potentially eliminates the need for full airplane tests. This methodology is based on comparing the applied EMI stress--the level of interference signal that arrives at a unit under test--versus the EMI strength of the unit--the interference level it can withstand without upset. This approach allows one to use computer models and/or low power coupling measurement and similarity (to other previously tested aircraft) to determine the stress applied to installed subsystems, and to use benchtop cable injection tests and/or mode stirred chamber radiated tests to determine the strength of the subsystem.
Date: July 1, 1993
Creator: Zacharias, R. A.; Avalle, C. A.; Kunz, K. S.; Molau, N. E.; Pennock, S. T.; Poggio, A. J. et al.
Partner: UNT Libraries Government Documents Department

Electromagnetic Interactions GEneRalized (EIGER): Algorithm abstraction and HPC implementation

Description: Modern software development methods combined with key generalizations of standard computational algorithms enable the development of a new class of electromagnetic modeling tools. This paper describes current and anticipated capabilities of a frequency domain modeling code, EIGER, which has an extremely wide range of applicability. In addition, software implementation methods and high performance computing issues are discussed.
Date: June 1, 1998
Creator: Sharpe, R.M.; Grant, J.B.; Champagne, N.J.; Wilton, D.R.; Jackson, D.R.; Johnson, W.A. et al.
Partner: UNT Libraries Government Documents Department

FY06 Engineering Research and Technology Report

Description: This report summarizes the core research, development, and technology accomplishments in Lawrence Livermore National Laboratory's Engineering Directorate for FY2006. These efforts exemplify Engineering's more than 50-year history of developing and applying the technologies needed to support the Laboratory's national security missions. A partner in every major program and project at the Laboratory throughout its existence, Engineering has prepared for this role with a skilled workforce and technical resources developed through both internal and external venues. These accomplishments embody Engineering's mission: ''Enable program success today and ensure the Laboratory's vitality tomorrow''. Engineering's investment in technologies is carried out primarily through two internal programs: the Laboratory Directed Research and Development (LDRD) program and the technology base, or ''Tech Base'', program. LDRD is the vehicle for creating technologies and competencies that are cutting-edge, or require discovery-class research to be fully understood. Tech Base is used to prepare those technologies to be more broadly applicable to a variety of Laboratory needs. The term commonly used for Tech Base projects is ''reduction to practice''. Thus, LDRD reports have a strong research emphasis, while Tech Base reports document discipline-oriented, core competency activities. This report combines the LDRD and Tech Base summaries into one volume, organized into six thematic technical areas: Engineering Modeling and Simulation; Measurement Technologies; Micro/Nano-Devices and Structures; Precision Engineering; Engineering Systems for Knowledge and Inference; and Energy Manipulation.
Date: January 22, 2007
Creator: Minichino, C; Alves, S W; Anderson, A T; Bennett, C V; Brown, C G; Brown, W D et al.
Partner: UNT Libraries Government Documents Department