Session: 21-01: Poster Session

Paper Number: 98316

98316 - Nonlinear Ultrasonic Techniques for the Quantification of Thermal Damage in Carbon/carbon Composite Material 

This research applies nonlinear ultrasonic (NLU) techniques for the quantitative characterization of Carbon/Carbon (C/C) composite friction materials. The characterization focuses on identifying thermal and oxidative damage induced by heat cycles during the lifespan of the material. Carbon/Carbon friction materials are subject to high service temperatures in air and thus susceptible to rapid oxidation damage [1], leading to a reduction in their mechanical properties and possibly shortening their lifespan. The nondestructive evaluation (NDE) of C/C composites could be used to quantify the damage state and help predict possible premature component failure.

Second harmonic generation (SHG) techniques based on the transmission of Rayleigh surface waves are used to measure the ultrasonic nonlinearity parameter, β. This ultrasonic nonlinearity parameter is sensitive to microstructural changes and has previously been used to characterize fatigue and thermal damage [2,3]. Experimental work has proven that β is a quantitative indicator of microstructural damage in carbon fiber reinforced composites [4]. This work aims at investigating the suitability of β as a quantitative indicator of thermal damage in C/C composites. The first task of this research is the ultrasonic material characterization of two different C/C friction material specimens in the as-received state. Suitable ultrasonic frequency ranges for analysis were identified in presence of the Floquet-type pass and stop bands [5], and wave velocities, attenuation and β are obtained. The composite microstructure is investigated by scanning electron microscopy (SEM) and electromagnetic (EM) spectroscopy and potential weight loss is recorded to correlate to the measured β. The second task of this work is to measure β after different durations of heat treatment in air at the expected operating temperature of the specimens. Heat treatment is used to simulate the thermal damage experienced during the specimens use. This work relates β to the oxidation state and thermal damage after heat treatment.

References
[1] Deng, Mengjia & Xia, Xiaoyu & Deng, Juanli & Hu, Kaiyue & Luan, Chenghua & Xu, Ma & Fan, Shangwu & Wang, Peng. (2022). Effective Anti-Oxidation Repair Coating for C/C Brake Materials Comprising Lead-Borosilicate and Bismuth-Borosilicate Glass. Materials. 15. 2827.

[2] J.-Y. Kim, L.J. Jacobs, J. Qu, J.W. Littles J. Acoust. Soc. Am. (2006), pp. 1266-1273

[3] A. Ruiz, N. Ortiz, A. Medina, J.-Y. Kim, L.J. Jacobs NDT&E Int., 54 (2013), pp. 19-26

[4] Andreades, Christos & Malfense Fierro, Gian Piero & Meo, Michele & Ciampa, Francesco. (2019). Nonlinear ultrasonic inspection of smart carbon fibre reinforced plastic composites with embedded piezoelectric lead zirconate titanate transducers for space applications. Journal of Intelligent Material Systems and Structures. 1-13.

[5] Datta, S.K., & Shah, A.H. (2009). Elastic Waves in Composite Media and Structures: With Applications to Ultrasonic Nondestructive Evaluation (1st ed.). CRC Press.

Presenting Author: Fabian Gmeiner School of Civil and Environmental Engineering, Georgia Institute of Technology