@inproceedings{721a9021453948e8821d8864a1e3ce0f,
title = "Effects of graphite porosity and anisotropy on measurements of elastic modulus using laser ultrasonics",
abstract = "Laser ultrasonic techniques can be used to study the ultrasonic properties of nuclear graphites and can serve as tools in establishing relationships between materials microstructure and the macroscopic stiffnesses of graphite. Establishing structure-property relationships permits improved ultrasonic sensing of graphite microstructural changes related to service-induced degradation. Laser ultrasonic measurements were made using a pulsed Nd:YAG laser source and detection was performed using a Michelson-type interferometer. This source-receiver combination provides for non-contacting, highly linear transduction of broadbanded, ultrasonic pulses permitting simultaneous determination of longitudinal and shear stiffnesses. Measurements show that among the graphites examined, a change in density of 0.21 g/cm3 (average 1.8 g/cm3) results in a change in the longitudinal elastic stiffness of 7.1 GPa (average 12.2 GPa) and 3.2 GPa (average 4.3 GPa) for the shear stiffness. Larger variations in density were produced by controlled oxidation of IG-110 and NBG-18. Shear wave birefringence measurements using laser line sources in IG-110 and PCEA indicate that IG-110 behaves isotropically while PCEA displays texture characteristic of transversely isotropic materials.",
keywords = "Young's modulus, anisotropy, graphite, laser ultrasonics, porosity, shear birefringence",
author = "Spicer, {James B.} and Zeng, {Fan W.} and Karen Han and Olasov, {Lauren R.} and Gallego, {Nidia C.} and Contescu, {Cristian I.}",
note = "Publisher Copyright: {\textcopyright} 2014 IEEE.; 2014 IEEE International Ultrasonics Symposium, IUS 2014 ; Conference date: 03-09-2014 Through 06-09-2014",
year = "2014",
month = oct,
day = "20",
doi = "10.1109/ULTSYM.2014.0059",
language = "English",
series = "IEEE International Ultrasonics Symposium, IUS",
publisher = "IEEE Computer Society",
pages = "232--235",
booktitle = "IEEE International Ultrasonics Symposium, IUS",
}