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3-d finite element model development for biomechanics: a software demonstration

3-d finite element model development for biomechanics: a software demonstration

Date: March 1, 1997
Creator: Hollerbach, K.; Hollister, A.M. & Ashby, E.
Description: Finite element analysis is becoming an increasingly important part of biomechanics and orthopedic research, as computational resources become more powerful, and data handling algorithms become more sophisticated. Until recently, tools with sufficient power did not exist or were not accessible to adequately model complicated, three-dimensional, nonlinear biomechanical systems. In the past, finite element analyses in biomechanics have often been limited to two-dimensional approaches, linear analyses, or simulations of single tissue types. Today, we have the resources to model fully three-dimensional, nonlinear, multi-tissue, and even multi-joint systems. The authors will present the process of developing these kinds of finite element models, using human hand and knee examples, and will demonstrate their software tools.
Contributing Partner: UNT Libraries Government Documents Department
A 3-d modular gripper design tool

A 3-d modular gripper design tool

Date: February 1, 1997
Creator: Brown, R.G. & Brost, R.C.
Description: Modular fixturing kits are sets of components used for flexible, rapid construction of fixtures. A modular vise is a parallel-jaw vise, each jaw of which is a modular fixture plate with a regular grid of precisely positioned holes. To fixture a part, one places pins in some of the holes so that when the vise is closed, the part is reliably located and completely constrained. The modular vise concept can be adapted easily to the design of modular parallel-jaw grippers for robots. By attaching a grid-plate to each jaw of a parallel-jaw gripper, one gains the ability to easily construct high-quality grasps for a wide variety of parts from a standard set of hardware. Wallack and Canny developed an algorithm for planning planar grasp configurations for the modular vise. In this paper, the authors expand this work to produce a 3-d fixture/gripper design tool. They describe several analyses they have added to the planar algorithm, including a 3-d grasp quality metric based on force information, 3-d geometric loading analysis, and inter-gripper interference analysis. Finally, the authors describe two applications of their code. One of these is an internal application at Sandia, while the other shows a potential use of the ...
Contributing Partner: UNT Libraries Government Documents Department
A 3-d modular gripper design tool

A 3-d modular gripper design tool

Date: January 1, 1997
Creator: Brown, R.G. & Brost, R.C.
Description: Modular fixturing kits are precisely machined sets of components used for flexible, short-turnaround construction of fixtures for a variety of manufacturing purposes. A modular vise is a parallel-jaw vise, where each jaw is a modular fixture plate with a regular grid of precisely positioned holes. A modular vise can be used to locate and hold parts for machining, assembly, and inspection tasks. To fixture a part, one places pins in some of the holes so that when the vise is closed, the part is reliably located and completely constrained. The modular vise concept can be adapted easily to the design of modular parallel-jaw grippers for robots. By attaching a grid plate to each jaw of a parallel-jaw gripper, the authors gain the ability to easily construct high-quality grasps for a wide variety of parts from a standard set of hardware. Wallack and Canny developed a previous algorithm for planning planar grasp configurations for the modular vise. In this paper, the authors expand this work to produce a 3-d fixture/gripper design tool. They describe several analyses added to the planar algorithm to improve its utility, including a three-dimensional grasp quality metric based on geometric and force information, three-dimensional geometric loading analysis, ...
Contributing Partner: UNT Libraries Government Documents Department
A 3-D numerical study of pinhole diffraction to predict the accuracy of EUV point diffraction interferometry

A 3-D numerical study of pinhole diffraction to predict the accuracy of EUV point diffraction interferometry

Date: December 1, 1995
Creator: Goldberg, K.A.; Tejnil, E. & Bokor, J.
Description: A 3-D electromagnetic field simulation is used to model the propagation of extreme ultraviolet (EUV), 13-nm, light through sub-1500 {Angstrom} dia pinholes in a highly absorptive medium. Deviations of the diffracted wavefront phase from an ideal sphere are studied within 0.1 numerical aperture, to predict the accuracy of EUV point diffraction interferometersused in at-wavelength testing of nearly diffraction-limited EUV optical systems. Aberration magnitudes are studied for various 3-D pinhole models, including cylindrical and conical pinhole bores.
Contributing Partner: UNT Libraries Government Documents Department
3-D spectral IP imaging: Non-invasive characterization of contaminant plumes. 1998 annual progress report

3-D spectral IP imaging: Non-invasive characterization of contaminant plumes. 1998 annual progress report

Date: June 1, 1998
Creator: Morgan, F.D.; Rodi, W. & Lesmes, D.
Description: 'The overall objective of this project is to develop the scientific basis for characterizing contaminant plumes in the earth''s subsurface using field measurements of induced polarization (IP) effects. Three specific objectives towards this end are: (1) understanding IP at the laboratory level through measurements of complex resistivity as a function of frequency in rock and soil samples with varying pore geometries, pore fluid conductivities and saturations, and contaminant chemistries and concentrations; (2) developing effective data acquisition techniques for measuring the critical IP responses (time domain or frequency domain) in the field; (3) developing modeling and inversion algorithms that permit the interpretation of field IP data in terms of subsurface geology and contaminant plume properties. The authors laboratory experiments to date are described in Appendices A and B, which consist of two papers submitted to the annual SAGEEP conference (Frye et al., 1998; Sturrock et al., 1998). The experiments involved measurements of complex resistivity vs. frequency on a suite of brine saturated sandstone samples. In one set of experiments, the fluid chemistry (pH, ionic strength, and cation type) was varied. In a second set of experiments, the microgeometry of the rock matrix was varied. The experiments showed that spectral IP responses ...
Contributing Partner: UNT Libraries Government Documents Department
3-D spectral IP imaging: Non-invasive characterization of contaminant plumes. Annual progress report, September 15, 1996--September 14, 1997

3-D spectral IP imaging: Non-invasive characterization of contaminant plumes. Annual progress report, September 15, 1996--September 14, 1997

Date: December 1, 1997
Creator: Frye, K.M.; Lesmes, D.P.; Morgan, F.D.; Rodi, W.; Shi, W. & Sturrock, J.
Description: 'The objective of this project is to develop the scientific basis for characterizing contaminant plumes in the earth''s subsurface using field measurements of induced polarization (IP) effects. The first-year accomplishments are (1) laboratory experiments on fluid-saturated sandstones quantifying the dependence of spectral IP responses on solution chemistry and rock micro-geometry; (2) library research on the current understanding of electromagnetic coupling effects on IP data acquired in the field: and (3) development of prototype forward modeling and inversion algorithms for interpreting IP data in terms of 3-D models of complex resistivity.'
Contributing Partner: UNT Libraries Government Documents Department
3-D Target Location from Stereoscopic SAR Images

3-D Target Location from Stereoscopic SAR Images

Date: October 1, 1999
Creator: DOERRY,ARMIN W.
Description: SAR range-Doppler images are inherently 2-dimensional. Targets with a height offset lay over onto offset range and azimuth locations. Just which image locations are laid upon depends on the imaging geometry, including depression angle, squint angle, and target bearing. This is the well known layover phenomenon. Images formed with different aperture geometries will exhibit different layover characteristics. These differences can be exploited to ascertain target height information, in a stereoscopic manner. Depending on the imaging geometries, height accuracy can be on the order of horizontal position accuracies, thereby rivaling the best IFSAR capabilities in fine resolution SAR images. All that is required for this to work are two distinct passes with suitably different geometries from any plain old SAR.
Contributing Partner: UNT Libraries Government Documents Department
3-D vertical seismic profiling at LLNL Site 300

3-D vertical seismic profiling at LLNL Site 300

Date: January 29, 1997
Creator: Bainer, R.; Rector, J. & Milligan, P.
Description: The initial goal of the 3-D Vertical Seismic Profiling (VSP) work at LLNL was to characterize seismic wave velocities and frequencies below the vadose zone to design the acquisition geometry for a 3-D shallow surface seismic reflection survey. VSPs are also used routinely to provide a link between surface seismic data and well logs. However, a test 2-D seismic line recorded at LLNL in the Spring of 1994 indicated that obtaining high quality reflection images below the vadose zone, yet shallower that 50 m, would require an expensive, very finely sampled survey ({lt} 1 m receiver spacing). Extensive image processing of the LLNL 2-D test line indicated that the only reliable reflection was from the top of the water table. Surprisingly, these results were very different than recent 3-D seismic work recorded at other sites, where high quality, high frequency surface (up to 300 Hz) reflection images were obtained as shallow as 20m. We believe that the differences are primarily due to the comparatively deep vadose zone at LLNL (15 to 30m) as compared to 0-5m at other sites. The thick vadose zone attenuates the reflection signals, particularly at the high frequencies (above 100 @). In addition, the vadose zone ...
Contributing Partner: UNT Libraries Government Documents Department
3-D woven, mullite matrix, composite filter

3-D woven, mullite matrix, composite filter

Date: December 1, 1995
Creator: Lane, J.E.; Painter, C.J. & Radford, K.C. LeCostaouec, J.F.
Description: Westinghouse, with Techniweave as a major subcontractor, is conducting a three-phase program aimed at providing advanced candle filters for a 1996 pilot scale demonstration in one of the two hot gas filter systems at Southern Company Service`s Wilsonville PSD Facility. The Base Program (Phases I and II) objective is to develop and demonstrate the suitability of the Westinghouse/Techniweave next generation composite candle filter for use in Pressurized Fluidized Bed Combustion (PFBC) and/or Integrated Gasification Combined Cycle (IGCC) power generation systems. The Optional Task (Phase M, Task 5) objective is to fabricate, inspect and ship to Wilsonville Hot gas particulate filters are key components for the successful commercializaion of advanced coal-based power-generation systems such as Pressurized Fluidized-bed Combustion (PFBC), including second-generation PFBC, and Integrated Gasification Combined Cycles (IGCC). Current generation monolithic ceramic filters are subject to catastrophic failure because they have very low resistance to crack propagation. To overcome this problem, a damage-tolerant ceramic filter element is needed.
Contributing Partner: UNT Libraries Government Documents Department
A 3-dimensional ray-trace model for predicting the performance of flashlamp-pumped laser amplifiers

A 3-dimensional ray-trace model for predicting the performance of flashlamp-pumped laser amplifiers

Date: February 13, 1997
Creator: Jancaitis, K.S.; Haney, S.W.; Munro, D.H.; Le Touze, G. & Cabourdin, O.
Description: We have developed a fully three-dimensional model for the performance of flashlamp pumped laser amplifiers. The model uses a reverse ray-trace technique to calculate the pumping of the laser glass by the flashlamp radiation. We have discovered several different methods by which we can speed up the calculation of the gain profile in a amplifier. The model predicts the energy-storage performance of the Beamlet amplifiers to better than 5%. This model will be used in the optimization of the National Ignition Facility (NIF) amplifier design.
Contributing Partner: UNT Libraries Government Documents Department