A study on ultrasonic evaluation of material defects in carbon/carbon composites

Im, Kwang Hee; Hsu, David K.; Cha, Cheon-Seok; Sim, Jae-Ki; Yang, In Young

doi:10.1007/bf03021667

Cited by 4 publications

(3 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Carbon matrix composites(CMC) are used for aircraft brake disks, space shuttle rocket nozzles, exhaust cones, air inlet channels, connecting rod, engine piston and turbine rotor [1] due to the advantages of very large strength-to-weight and stiffness-to-weight ratios and also to high temperature resistance [2]. Manufacturing process for the CMCs is rather complex as compared with that for conventional composites like Graphite/Epoxy due to the multiple steps involved in the carbonization and densification cycles which improved density and thermal conductivity.…”

Section: Introductionmentioning

confidence: 99%

Inspection of Inhomogeneities in Carbon/Phenolic Matrix Composite Materials Using NDE Techniques

Hsu

Yang

2004

KEM

View full text Add to dashboard Cite

Carbon matrix composite (CMC) materials consist of carbon fibers embedded in a carbonaceous matrix. Due to low density, high thermal conductivity and excellent mechanical properties at elevated temperatures, the CMCs are applied to aircraft brake disks. The properties of CMC are dependent on the manufacturing methods used for production and fiber arrangement. It is desirable to perform nondestructive evaluation of material properties and part homogeneity for structural integrity of CMC brake disks. In this paper several ultrasonic techniques were applied to carbon matrix composites for the evaluation of spatial variations in material properties which are attributable to the manufacturing process. For a carbon matrix composite manufactured by chemical vapor infiltration (CVI) method, the spatial variation of ultrasonic velocity was found to be influenced by the densification behavior in CVI process. Ultrasonic velocity and attenuation depend on a density variation of materials. Low frequency through-transmission scans based on both amplitude and time-of-flight of the ultrasonic pulse were used for mapping out the material property inhomogeneity. Also a motorized system was adopted to measure ultrasonic velocity at a local point in CMC materials under the same coupling conditions. Manual results were comparable with those obtained by the motorized system using dry-coupling ultrasonics and through transmission method in immersion. Pulse-echo C-scans were used to image near-surface material property anomalies during CVI process.

show abstract

Section: Introductionmentioning

confidence: 99%

Inspection of Inhomogeneities in Carbon/Phenolic Matrix Composite Materials Using NDE Techniques

Hsu

Yang

2004

KEM

View full text Add to dashboard Cite

show abstract

“…(24,26,28,36,37) 2) Non-destructive method These methods do not require section the samples, which are ultrasonic technique, X-ray radiography, micro-computed tomography (micro-CT) and optical coherence tomography (OCT). (32,33,(38)(39)(40) a) Ultrasonic technique Ultrasonic C scan imaging is an effective NDE technique used for material analysis. C-scan imaging is used to map variations in ultrasonic echo peak amplitude that occur when scanning across a material part.…”

Section: ) Destructive Methodsmentioning

confidence: 99%

“…It provides quantitatively a two-dimensional view of a specimen in which differences in image contrast result from the objects interaction with an impinging ultrasonic wave. (40) b) Micro-computed tomography (micro-CT) Micro-computed tomography differs from conventional medical CAT-scanning in its ability to resolve details as small as a few micrometers in size. It is a nondestructive technique for visualizing object interiors.…”

Section: ) Destructive Methodsmentioning

confidence: 99%

Evaluation of voids in class ii restorations restored with bulk-fill and conventional nanohybrid resin composite

Chaidarun

View full text Add to dashboard Cite

Objectives: The aim of the study was to evaluate the influence of four resin composites on voids in small and large Class II cavities. Furthermore, the thickness of the first increment of the restorations was studied. Methods: Eighty artificial lower second premolars were divided into two preparation designs with 40 standardized Class II cavities in each, and then restored with four resin composites (three bulk-fill types: SonicFill 2, Filtek Bulk Fill (capsule), Filtek Bulk Fill (syringe) and a conventional nanohybrid resin composite: Premise). Restorations were sectioned for microscopic evaluation and a Kruskal-Wallis analysis was performed to evaluate the number of voids and percent void area. The thickness of the first increment was measured and analyzed. Results: There were significant differences in the number of voids and percent void area among the 4 groups in small cavities. SonicFill 2 and Filtek Bulk Fill (capsule) placed with the injection technique showing reduced voids. In contrast, no significant differences were detected among the 4 groups in large cavities. Most of the first increment thicknesses of the restorations in both cavity preparations were thicker than recommended. Conclusions: Voids were reduced when the injectable resin composites were applied in small Class II cavity preparations, and the best results were achieved using SonicFill 2.

show abstract

Studies on the correlation between mechanical properties and ultrasonic parameters of aging lCr-lMo-0.25V steel

Seok

Kim

2005

J Mech Sci Technol

View full text Add to dashboard Cite

A study on ultrasonic evaluation of material defects in carbon/carbon composites

Cited by 4 publications

References 11 publications

Inspection of Inhomogeneities in Carbon/Phenolic Matrix Composite Materials Using NDE Techniques

Inspection of Inhomogeneities in Carbon/Phenolic Matrix Composite Materials Using NDE Techniques

Evaluation of voids in class ii restorations restored with bulk-fill and conventional nanohybrid resin composite

Studies on the correlation between mechanical properties and ultrasonic parameters of aging lCr-lMo-0.25V steel

Contact Info

Product

Resources

About