A Morphological Study of Porosity Defects in Graphite-Epoxy Composites

Hsu, David K.; Uhl, K. M.

doi:10.1007/978-1-4613-1893-4_134

Cited by 29 publications

(27 citation statements)

References 3 publications

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“…This represents a far more uniform percentage increase in backscatter over azimuthal angle than was previously reported in work which considered the effects of introducing spherical inclusions (glass spheres) into a fiber-reinforced matrix [3). The explanation for this more uniform percentage increase is possibly provided by the cylindrical morphology of porosity observed in the specimens of this study [6). It is conceivable that scattering from cylindrical porosity displays an angular dependence quite similar to scattering by the fiber-related internal structures.…”

Section: Angular Dependence Of Backscattermentioning

confidence: 58%

Porosity Characterization in Fiber-Reinforced Composites by Use of Ultrasonic Backscatter

Roberts

1987

Review of Progress in Quantitative Nondestructive Evaluation

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Section: Angular Dependence Of Backscattermentioning

confidence: 58%

Porosity Characterization in Fiber-Reinforced Composites by Use of Ultrasonic Backscatter

Roberts

1987

Review of Progress in Quantitative Nondestructive Evaluation

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“…The porosity in these specimens has been shown to possess a cylindrical morphology [9]. Likewise, the fiber-related inhomogeneities possess a cylindrical morphology.…”

Section: Angular Dependence Of Backscattermentioning

confidence: 91%

Characterization of Porosity in Continuous Fiber-Reinforced Composites with Ultrasonic Backscatter

Roberts

1988

Review of Progress in Quantitative Nondestructive Evaluation

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“…Equation ( In order to analyze scattering amplitude distributions in a research environment, a flaw distribution must be assumed. In certain cases, the size distribution associated with voids or Inclusions is approximately lognormal (Hatch and Choate 1929, Hatch 1933, Kottler 1950, Hahn and Shapiro 1967, Gubernatis and Domany 1983, Thompson et al 1983a, Hsu and Uhl 1987. The random variable analyses and subsequent filter analyses Note as demonstrated by the figure, the lower the low coefficient of variation the more symmetric and Gaussian the lognormal distribution (Hatch and Choate 1929, Hahn and Shapiro 1967, Haugen 1968).…”

Section: Distributionmentioning

confidence: 96%

A prior knowledge based optimal Wiener filtering approach to ultrasonic scattering amplitude estimation

Neal

Thompson

1989

The Journal of the Acoustical Society of America

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, "A prior knowledge based optimal Wiener filtering approach to ultrasonic scattering amplitude estimation " (1988). Retrospective Theses and Dissertations. 8877. http://lib.dr.iastate.edu/rtd/8877 INFORMATION TO USERSThe most advanced technology has been used to photo graph and reproduce this manuscript from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer.The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction.In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion.Oversize materials (e.g., maps, drawings, charts) are re produced by sectioning the original, beginning at the upper left-hand corner and continuing from left to right in equal sections with small overlaps. Each original is also photographed in one exposure and is included in reduced form at the back of the book. These are also available as one exposure on a standard 35mm slide or as a 17" x 23" black and white photographic print for an additional charge.Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6" x 9" black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. Signature was redacted for privacy.Signature was redacted for privacy.Signature was redacted for privacy. The work reported here is associated with flaw characterization.This work is motivated from an engineering perspective by considering two fundamentally different approaches to life prediction that can be found in fatigue of materials and structures. In a simplistic sense, a "safe life"or "zero defects" fatigue life prediction approach (Coffin and Tiffany 1976) assumes that once a flaw is macroscopic, i.e., once a flaw has grown to a size which can be detected by NDE techniques, failure is imminent and the component must be taken out of service. With this approach, qualitative NDE indicating the presence or absence of a flaw provides sufficient information to determine if a component should be retired. An alternative approach, which is sometimes referred to as a "damage tolerance" approach, is based on a fracture mechanics methodology (Coffin and Tiffany 1976, Rolfe and Barsom 1977). With this approach, instead of assuming that all flawed components must be taken out of service, the 2 severity of the flaw is assessed and a more rational determination of the remaining life of the component is made. To implement this approach, quantitative flaw characterization is required. As a minimum...

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A Morphological Study of Porosity Defects in Graphite-Epoxy Composites

Cited by 29 publications

References 3 publications

Porosity Characterization in Fiber-Reinforced Composites by Use of Ultrasonic Backscatter

Porosity Characterization in Fiber-Reinforced Composites by Use of Ultrasonic Backscatter

Characterization of Porosity in Continuous Fiber-Reinforced Composites with Ultrasonic Backscatter

A prior knowledge based optimal Wiener filtering approach to ultrasonic scattering amplitude estimation

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