Richard Rauser - Profile on Academia.edu (original) (raw)

Papers by Richard Rauser

During the fabrication of braided carbon fiber composite materials, process variations occur whic... more During the fabrication of braided carbon fiber composite materials, process variations occur which affect the fiber architecture. Quantitative measurements of local and global fiber architecture variations are needed to determine the potential effect of process variations on mechanical properties of the cured composite. Although non-destructive inspection via X-ray CT imaging is a promising approach, difficulties in quantitative analysis of the data arise due to the similar densities of the material constituents. In an effort to gain more quantitative information about features related to fiber architecture, methods have been explored to improve the details that can be captured by X-ray CT imaging. Metal-coated fibers and thin veils are used as inserts to extract detailed information about fiber orientations and inter-ply behavior from X-ray CT images.

Nondestructive Evaluation of Programmed Defects in Ti-6Al-4V L-PBF ASTM E8-Compliant Dog-Bone Samples

Structural Integrity of Additive Manufactured Parts, 2020

During the fabrication of braided carbon fiber composite materials, process variations occur whic... more During the fabrication of braided carbon fiber composite materials, process variations occur which affect the fiber architecture. Quantitative measurements of local and global fiber architecture variations are needed to determine the potential effect of process variations on mechanical properties of the cured composite. Although non-destructive inspection via X-ray CT imaging is a promising approach, difficulties in quantitative analysis of the data arise due to the similar densities of the material constituents. In an effort to gain more quantitative information about features related to fiber architecture, methods have been explored to improve the details that can be captured by X-ray CT imaging. Metal-coated fibers and thin veils are used as inserts to extract detailed information about fiber orientations and inter-ply behavior from X-ray CT images.

AIP Conference Proceedings, 2012

A terahertz axial computed tomography system has been developed that uses time domain measurement... more A terahertz axial computed tomography system has been developed that uses time domain measurements in order to form cross-sectional image slices and three-dimensional volume renderings of terahertz-transparent materials. The system can inspect samples as large as 0.0283 m 3 (1 ft 3) with no safety concerns as for x-ray computed tomography. In this study, the system is evaluated for its ability to detect and characterize flat bottom holes, drilled holes, and embedded voids in foam materials utilized as thermal protection on the external fuel tanks for the Space Shuttle. X-ray micro-computed tomography was also performed on the samples to compare against the terahertz computed tomography results and better define embedded voids. Limits of detectability based on depth and size for the samples used in this study are loosely defined. Image sharpness and morphology characterization ability for terahertz computed tomography are qualitatively described.

Recent Improvements in Display and Analysis of Nde Data at Nasa

AIP Conference Proceedings, 2011

This talk reviews several recent NDE data visualization and analysis improvements implemented at ... more This talk reviews several recent NDE data visualization and analysis improvements implemented at NASA Glenn Research Center. Examples will be shown in the areas of X-ray computed tomography and waveform-based NDE. Emphasis is on methods that are most useful not only for the NDE professional analyzing the data but also for sharing of the data with customers such as material

A combined NDT/fatigue test and three dimensional image processing study of a SIC/SIC composite system

Materials evaluation, 2004

NASA/TM—2000-209952 Challenges in Integrating Nondestructive Evaluation and Finite Element Methods for Realistic Structural Analysis

Since its founding, NASA has been dedicated to the advancement of aeronautics and space

Materials evaluation, 2010

In this investigation, a T-shaped aluminum alloy isogrid stiffener element used in aerospace appl... more In this investigation, a T-shaped aluminum alloy isogrid stiffener element used in aerospace applications was tested with ultrasonic phased array techniques. The isogrid stiffener element had various crack configurations emanating from bolt holes. Computational simulation methods were used to mimic the experiments in order to help understand experimental results. The results of this study indicate that it is at least partly feasible to interrogate this type of geometry with the given discontinuity configurations using phased array ultrasonics. The simulation methods were critical in helping explain the experimental results and, with some limitation, can be used to predict testing results.

NDE Software Developed at NASA Glenn Research Center

NASA Glenn Research Center has developed several important Nondestructive Evaluation (NDE) relate... more NASA Glenn Research Center has developed several important Nondestructive Evaluation (NDE) related software packages for different projects in the last 10 years. Three of the software packages have been created with commercial-grade user interfaces and are available to United States entities for download on the NASA Technology Transfer and Partnership Office server (https://sr.grc.nasa.gov/). This article provides brief overviews of the software packages.

Novel Method Used to Inspect Curved and Tubular Structural Materials

At the NASA Lewis Research Center, a technique for the ultrasonic characterization of plates has ... more At the NASA Lewis Research Center, a technique for the ultrasonic characterization of plates has been extended to tubes and to curved structures in general. In this technique, one performs measurements that yield a thickness-independent value of the local through-the-thickness speed of sound in a specimen. From such measurements at numerous locations across the specimen, one can construct a map of velocity as a function of location. The gradients of velocity indicated by such a map indicate local through-the-thickness-averaged microstructural parameters that affect the speed of sound. Such parameters include the pore volume fraction, mass density, fiber volume fraction (in the case of a composite material), and chemical composition. Apparatus was designed to apply the technique to tubular and other curved specimens.

The Critical Role of High Resolution X-ray Micro-computed Tomography for Ultra-thin Wall Space Component Characterization

Materials evaluation, 2014

A high resolution micro-computed tomography (μCT) system complemented by specialized hardware and... more A high resolution micro-computed tomography (μCT) system complemented by specialized hardware and software tools were used to provide quantitative characterization for a tapered ultrathin wall space component at NASA. The CT data served two purposes: first to assess whether an acceptable flaw condition based on acceptable use requirements existed and second to provide comprehensive flaw measurements for life modeling. Regarding the latter, the measurements were used in a fracture-mechanicsbased model to determine whether the components would be expected to survive four service lifes. This article will describe component acceptance criteria; the CT system hardware and procedure; detectability and measurement error assessment of the CT system, specialized software needed to aid the characterization process; example CT results; correlation with optical/SEM characterization; and an overview of the modeling technique utilizing the CT data.

A novel software method is presented that is applicable for analyzing cylindrical and partially c... more A novel software method is presented that is applicable for analyzing cylindrical and partially cylindrical objects inspected using computed tomography. This method involves unwrapping and re-slicing data so that the CT data from the cylindrical object can be viewed as a series of 2-D sheets in the vertical direction in addition to volume rendering and normal plane views provided by traditional CT software. The method is based on interior and exterior surface edge detection and under proper conditions, is FULLY AUTOMATED and requires no input from the user except the correct voxel dimension from the CT scan. The software is available from NASA in 32- and 64-bit versions that can be applied to gigabyte-sized data sets, processing data either in random access memory or primarily on the computer hard drive. Please inquire with the presenting author if further interested. This software differentiates itself in total from other possible re-slicing software solutions due to complete autom...

A combined NDE-fatigue testing and three-dimensional image processing study of a SiC/SiC composite system

SPIE Proceedings, 2004

Non destructive evaluation (NDE) is a critical technology for improving the quality of a componen... more Non destructive evaluation (NDE) is a critical technology for improving the quality of a component in a cost-sparing production environment. NDE detects variations in a material or a component without altering or damaging the test piece. Using these techniques to improve the production process requires characterization of the faults and their influence on the component performance. This task depends on

Structural assessment of metal foam

A combined NDE/FEA approach to evaluate the structural response of a metal foam

Behavior and Mechanics of Multifunctional and Composite Materials 2007, 2007

Metal foams are expected to find use in structural applications where weight is of particular con... more Metal foams are expected to find use in structural applications where weight is of particular concern, such as space vehicles, rotorcraft blades, car bodies or portable electronic devices. The obvious structural application of metal foam is for light weight sandwich panels, made up of thin solid face sheets and a metallic foam core. The stiffness of the sandwich structure is

Nondestructive Evaluation of Aging Materials and Composites IV, 2000

Capabilities and expertise related to the development of links between nondestructive evaluation ... more Capabilities and expertise related to the development of links between nondestructive evaluation (NDE) and finite element analysis (FEA) at Glenn Research Center (GRC) are demonstrated. Current tools to analyze data produced by computed tomography (CT) scans are exercised to help assess the damage state in high temperature structural composite materials. A utility translator was written to convert velocity 2 (an image processing software) STL data file to a suitable CAD-FEA type file. Finite element analyses are carried out with MARC, a commercial nonlinear finite element code, and the analytical results are discussed. Modeling was established by building a MSC/Patran (a pre and post processing finite element package) generated model and comparing it to a model generated by Velocity 2 in conjunction with MSC/Patran Graphics. Modeling issues and results are discussed in this paper. The entire process that outlines the tie between the data extracted via NDE and the finite element modeling and analysis is fully described.

Nondestructive Testing Software Developed at NASA Glenn Research Center

Materials evaluation, 2015

Structural assessment of metal foam using combined NDE and FEA

Proceedings of SPIE, 2005

Structural assessment of metal foam using combined NDE and FEA. [Proceedings of SPIE 5767, 248 (2... more Structural assessment of metal foam using combined NDE and FEA. [Proceedings of SPIE 5767, 248 (2005)]. Louis J. Ghosn, Ali Abdul-Aziz, Philippe G. Young, Richard W. Rauser. Abstract. Metal foams are expected to find use ...

A study was performed on the effect of experimental variables on radiographic sensitivity (image ... more A study was performed on the effect of experimental variables on radiographic sensitivity (image quality) in x-ray micro-computed tomography images for a high density thin wall metallic cylinder containing micro-EDM holes. Image quality was evaluated in terms of signal-to-noise ratio, flaw detectability, and feature sharpness. The variables included: day-to-day reproducibility, current, integration time, voltage, filtering, number of frame averages, number of projection views, beam width, effective object radius, binning, orientation of sample, acquisition angle range (180° to 360°), and directional versus transmission tube.

Nondestructive Evaluation and Health Monitoring of Aerospace Materials and Composites III, 2004

Non destructive evaluation (NDE) is a critical technology for improving the quality of a componen... more Non destructive evaluation (NDE) is a critical technology for improving the quality of a component in a cost-sparing production environment. NDE detects variations in a material or a component without altering or damaging the test piece. Using these techniques to improve the production process requires characterization of the faults and their influence on the component performance. This task depends on

During the fabrication of braided carbon fiber composite materials, process variations occur whic... more During the fabrication of braided carbon fiber composite materials, process variations occur which affect the fiber architecture. Quantitative measurements of local and global fiber architecture variations are needed to determine the potential effect of process variations on mechanical properties of the cured composite. Although non-destructive inspection via X-ray CT imaging is a promising approach, difficulties in quantitative analysis of the data arise due to the similar densities of the material constituents. In an effort to gain more quantitative information about features related to fiber architecture, methods have been explored to improve the details that can be captured by X-ray CT imaging. Metal-coated fibers and thin veils are used as inserts to extract detailed information about fiber orientations and inter-ply behavior from X-ray CT images.

Nondestructive Evaluation of Programmed Defects in Ti-6Al-4V L-PBF ASTM E8-Compliant Dog-Bone Samples

Structural Integrity of Additive Manufactured Parts, 2020

During the fabrication of braided carbon fiber composite materials, process variations occur whic... more During the fabrication of braided carbon fiber composite materials, process variations occur which affect the fiber architecture. Quantitative measurements of local and global fiber architecture variations are needed to determine the potential effect of process variations on mechanical properties of the cured composite. Although non-destructive inspection via X-ray CT imaging is a promising approach, difficulties in quantitative analysis of the data arise due to the similar densities of the material constituents. In an effort to gain more quantitative information about features related to fiber architecture, methods have been explored to improve the details that can be captured by X-ray CT imaging. Metal-coated fibers and thin veils are used as inserts to extract detailed information about fiber orientations and inter-ply behavior from X-ray CT images.

AIP Conference Proceedings, 2012

A terahertz axial computed tomography system has been developed that uses time domain measurement... more A terahertz axial computed tomography system has been developed that uses time domain measurements in order to form cross-sectional image slices and three-dimensional volume renderings of terahertz-transparent materials. The system can inspect samples as large as 0.0283 m 3 (1 ft 3) with no safety concerns as for x-ray computed tomography. In this study, the system is evaluated for its ability to detect and characterize flat bottom holes, drilled holes, and embedded voids in foam materials utilized as thermal protection on the external fuel tanks for the Space Shuttle. X-ray micro-computed tomography was also performed on the samples to compare against the terahertz computed tomography results and better define embedded voids. Limits of detectability based on depth and size for the samples used in this study are loosely defined. Image sharpness and morphology characterization ability for terahertz computed tomography are qualitatively described.

Recent Improvements in Display and Analysis of Nde Data at Nasa

AIP Conference Proceedings, 2011

This talk reviews several recent NDE data visualization and analysis improvements implemented at ... more This talk reviews several recent NDE data visualization and analysis improvements implemented at NASA Glenn Research Center. Examples will be shown in the areas of X-ray computed tomography and waveform-based NDE. Emphasis is on methods that are most useful not only for the NDE professional analyzing the data but also for sharing of the data with customers such as material

A combined NDT/fatigue test and three dimensional image processing study of a SIC/SIC composite system

Materials evaluation, 2004

NASA/TM—2000-209952 Challenges in Integrating Nondestructive Evaluation and Finite Element Methods for Realistic Structural Analysis

Since its founding, NASA has been dedicated to the advancement of aeronautics and space

Materials evaluation, 2010

In this investigation, a T-shaped aluminum alloy isogrid stiffener element used in aerospace appl... more In this investigation, a T-shaped aluminum alloy isogrid stiffener element used in aerospace applications was tested with ultrasonic phased array techniques. The isogrid stiffener element had various crack configurations emanating from bolt holes. Computational simulation methods were used to mimic the experiments in order to help understand experimental results. The results of this study indicate that it is at least partly feasible to interrogate this type of geometry with the given discontinuity configurations using phased array ultrasonics. The simulation methods were critical in helping explain the experimental results and, with some limitation, can be used to predict testing results.

NDE Software Developed at NASA Glenn Research Center

NASA Glenn Research Center has developed several important Nondestructive Evaluation (NDE) relate... more NASA Glenn Research Center has developed several important Nondestructive Evaluation (NDE) related software packages for different projects in the last 10 years. Three of the software packages have been created with commercial-grade user interfaces and are available to United States entities for download on the NASA Technology Transfer and Partnership Office server (https://sr.grc.nasa.gov/). This article provides brief overviews of the software packages.

Novel Method Used to Inspect Curved and Tubular Structural Materials

At the NASA Lewis Research Center, a technique for the ultrasonic characterization of plates has ... more At the NASA Lewis Research Center, a technique for the ultrasonic characterization of plates has been extended to tubes and to curved structures in general. In this technique, one performs measurements that yield a thickness-independent value of the local through-the-thickness speed of sound in a specimen. From such measurements at numerous locations across the specimen, one can construct a map of velocity as a function of location. The gradients of velocity indicated by such a map indicate local through-the-thickness-averaged microstructural parameters that affect the speed of sound. Such parameters include the pore volume fraction, mass density, fiber volume fraction (in the case of a composite material), and chemical composition. Apparatus was designed to apply the technique to tubular and other curved specimens.

The Critical Role of High Resolution X-ray Micro-computed Tomography for Ultra-thin Wall Space Component Characterization

Materials evaluation, 2014

A high resolution micro-computed tomography (μCT) system complemented by specialized hardware and... more A high resolution micro-computed tomography (μCT) system complemented by specialized hardware and software tools were used to provide quantitative characterization for a tapered ultrathin wall space component at NASA. The CT data served two purposes: first to assess whether an acceptable flaw condition based on acceptable use requirements existed and second to provide comprehensive flaw measurements for life modeling. Regarding the latter, the measurements were used in a fracture-mechanicsbased model to determine whether the components would be expected to survive four service lifes. This article will describe component acceptance criteria; the CT system hardware and procedure; detectability and measurement error assessment of the CT system, specialized software needed to aid the characterization process; example CT results; correlation with optical/SEM characterization; and an overview of the modeling technique utilizing the CT data.

A novel software method is presented that is applicable for analyzing cylindrical and partially c... more A novel software method is presented that is applicable for analyzing cylindrical and partially cylindrical objects inspected using computed tomography. This method involves unwrapping and re-slicing data so that the CT data from the cylindrical object can be viewed as a series of 2-D sheets in the vertical direction in addition to volume rendering and normal plane views provided by traditional CT software. The method is based on interior and exterior surface edge detection and under proper conditions, is FULLY AUTOMATED and requires no input from the user except the correct voxel dimension from the CT scan. The software is available from NASA in 32- and 64-bit versions that can be applied to gigabyte-sized data sets, processing data either in random access memory or primarily on the computer hard drive. Please inquire with the presenting author if further interested. This software differentiates itself in total from other possible re-slicing software solutions due to complete autom...

A combined NDE-fatigue testing and three-dimensional image processing study of a SiC/SiC composite system

SPIE Proceedings, 2004

Non destructive evaluation (NDE) is a critical technology for improving the quality of a componen... more Non destructive evaluation (NDE) is a critical technology for improving the quality of a component in a cost-sparing production environment. NDE detects variations in a material or a component without altering or damaging the test piece. Using these techniques to improve the production process requires characterization of the faults and their influence on the component performance. This task depends on

Structural assessment of metal foam

A combined NDE/FEA approach to evaluate the structural response of a metal foam

Behavior and Mechanics of Multifunctional and Composite Materials 2007, 2007

Metal foams are expected to find use in structural applications where weight is of particular con... more Metal foams are expected to find use in structural applications where weight is of particular concern, such as space vehicles, rotorcraft blades, car bodies or portable electronic devices. The obvious structural application of metal foam is for light weight sandwich panels, made up of thin solid face sheets and a metallic foam core. The stiffness of the sandwich structure is

Nondestructive Evaluation of Aging Materials and Composites IV, 2000

Capabilities and expertise related to the development of links between nondestructive evaluation ... more Capabilities and expertise related to the development of links between nondestructive evaluation (NDE) and finite element analysis (FEA) at Glenn Research Center (GRC) are demonstrated. Current tools to analyze data produced by computed tomography (CT) scans are exercised to help assess the damage state in high temperature structural composite materials. A utility translator was written to convert velocity 2 (an image processing software) STL data file to a suitable CAD-FEA type file. Finite element analyses are carried out with MARC, a commercial nonlinear finite element code, and the analytical results are discussed. Modeling was established by building a MSC/Patran (a pre and post processing finite element package) generated model and comparing it to a model generated by Velocity 2 in conjunction with MSC/Patran Graphics. Modeling issues and results are discussed in this paper. The entire process that outlines the tie between the data extracted via NDE and the finite element modeling and analysis is fully described.

Nondestructive Testing Software Developed at NASA Glenn Research Center

Materials evaluation, 2015

Structural assessment of metal foam using combined NDE and FEA

Proceedings of SPIE, 2005

Structural assessment of metal foam using combined NDE and FEA. [Proceedings of SPIE 5767, 248 (2... more Structural assessment of metal foam using combined NDE and FEA. [Proceedings of SPIE 5767, 248 (2005)]. Louis J. Ghosn, Ali Abdul-Aziz, Philippe G. Young, Richard W. Rauser. Abstract. Metal foams are expected to find use ...

A study was performed on the effect of experimental variables on radiographic sensitivity (image ... more A study was performed on the effect of experimental variables on radiographic sensitivity (image quality) in x-ray micro-computed tomography images for a high density thin wall metallic cylinder containing micro-EDM holes. Image quality was evaluated in terms of signal-to-noise ratio, flaw detectability, and feature sharpness. The variables included: day-to-day reproducibility, current, integration time, voltage, filtering, number of frame averages, number of projection views, beam width, effective object radius, binning, orientation of sample, acquisition angle range (180° to 360°), and directional versus transmission tube.

Nondestructive Evaluation and Health Monitoring of Aerospace Materials and Composites III, 2004

Non destructive evaluation (NDE) is a critical technology for improving the quality of a componen... more Non destructive evaluation (NDE) is a critical technology for improving the quality of a component in a cost-sparing production environment. NDE detects variations in a material or a component without altering or damaging the test piece. Using these techniques to improve the production process requires characterization of the faults and their influence on the component performance. This task depends on