Heat Induced Damage Detection by Terahertz THz R

Authors: Ehsan Kabiri Rahani Tribikram Kundu Ziran Wu Hao Xin

Publish Date: 2011/04/05

Volume: 32, Issue: 6, Pages: 848-856

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Abstract

Terahertz THz and subterahertz imaging and spectroscopy are becoming increasingly popular nondestructive evaluation techniques for damage detection and characterization of materials THz radiation is being used for inspecting ceramic foam tiles used in TPS Thermal Protection System thick polymer composites and polymer tiles that are not good conductors of ultrasonic waves Capability of THz electromagnetic waves in detecting heat induced damage in porous materials is investigated in this paper Porous pumice stone blocks are subjected to long time heat exposures to produce heat induced damage in the block The dielectric properties extracted from THz TDS Time Domain Spectroscopy measurements are compared for different levels of heat exposure Experimental results show noticeable and consistent change in dielectric properties with increasing levels of heat exposure well before its melting pointThis research was financially supported from the Air Force Office of Scientific Research AFOSR grant FA95500810318 Program managers are Dr Victor Giurgiutiu and Dr David Stargel Ziran Wu and Hao Xin thank National Science Foundation NSF for partial support through Awards 0823864 and 0925220 The results and conclusions presented here are those of the authors and do not represent the views of AFOSR or NSF

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