Nondestructive Damage Evaluation in Ceramic Matrix Composites for Aerospace Applications

Konstantinos G Dassios,Dimitrios G Aggelis,Theodore E Matikas,Evangelos Z Kordatos

doi:10.1155/2013/715945

Konstantinos G Dassios, Dimitrios G Aggelis + Show 2 more

Open Access

https://doi.org/10.1155/2013/715945

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Abstract

Infrared thermography (IRT) and acoustic emission (AE) are the two major nondestructive methodologies for evaluating damage in ceramic matrix composites (CMCs) for aerospace applications. The two techniques are applied herein to assess and monitor damage formation and evolution in a SiC-fiber reinforced CMC loaded under cyclic and fatigue loading. The paper explains how IRT and AE can be used for the assessment of the material's performance under fatigue. IRT and AE parameters are specifically used for the characterization of the complex damage mechanisms that occur during CMC fracture, and they enable the identification of the micromechanical processes that control material failure, mainly crack formation and propagation. Additionally, these nondestructive parameters help in early prediction of the residual life of the material and in establishing the fatigue limit of materials rapidly and accurately.

Highlights

Owing to their unique properties such as damage tolerance, fracture toughness, wear and corrosion resistance with respect to monolithic ceramics, and crack growth resistance, ceramic matrix composites (CMCs) can withstand severe thermomechanical loading conditions [1] and are used today in many aerospace applications as braking systems, structural components, nozzles, and thermal barriers
Infrared thermography (IRT) and acoustic emission (AE) parameters are used for the characterization of the complex damage mechanisms that occur during CMC fracture, and they enable the identification of the micromechanical processes that control material failure, mainly crack formation and propagation
While IRT captures the thermal energy emissivity of the specimen which is directly related to the damage mechanisms that form and develop during material fracture, the idea behind AE monitoring is that any fracture incident inside a material releases energy which propagates in the form of elastic waves and can be captured at the surface of the material by appropriate sensors

Summary

Introduction

Owing to their unique properties such as damage tolerance, fracture toughness, wear and corrosion resistance with respect to monolithic ceramics, and crack growth resistance, CMCs can withstand severe thermomechanical loading conditions [1] and are used today in many aerospace applications as braking systems, structural components, nozzles, and thermal barriers. Among the highly sought-after nondestructive methods capable of monitoring the structural integrity of aerospace structures in an efficient and economical manner, infrared thermography and acoustic emission stand out for being fast, straightforward, and highly reliable. Today both the National Aeronautics and Space Administration (NASA) and Astrium, the European space company, use IRT and AE to detect defects in shuttle wings, rudders and tails, thruster chamber assemblies, and other composite components [3,4,5,6,7,8]. The significance of a large number of IRT and AE indices with respect to mechanical performance and damage evaluation is discussed and explained in the text

Experimental

Results and Discussion

Thermography

Acoustic Emission

Conclusions