Phased array techniques for damage detection in aerospace structures

The future of aerospace structures is highly dependent on the advancement of reliable and high-performance materials, such as composite materials and metals. Innovation in high resolution non-invasive evaluation of these materials is needed for their qualification and monitoring for structural integrity. Aluminum oxide (or α-alumina) nanoparticles present photoluminescent properties that allow stress and damage sensing via photoluminescence piezospectroscopy. This work describes how these nanoparticles are added into a polymer matrix to create functional coatings that monitor the damage of the underlying composite or metallic substrates. Different volume fractions of α-alumina nanoparticles in the piezospectroscopic coatings were studied for determining the sensitivity of the coatings and successful damage detection was demonstrated for an open-hole tension composite substrate as well as 2024 aluminum tensile substrates with a subsurface notch.

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Application of Phased Array Antenna Technique in Structural Damage Detection

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.368-373.1667 ◽

2011 ◽

Vol 368-373 ◽

pp. 1667-1671

Author(s):

Yu Zhang ◽

Long Yu ◽

Yun Ju Yan ◽

Yu Guo

Keyword(s):

Wave Propagation ◽

Damage Detection ◽

Structural Damage ◽

Phased Array ◽

Tone Burst ◽

Array Antenna ◽

Detection Accuracy ◽

Structural Damage Detection ◽

Phased Array Antenna ◽

Energy Leakage

Over decades phased array antenna technique attracts much more attention in Lamb wave based structural damage detection. Lamb wave generated by the piezoelectric wafers omnidirectionally could be steered at a specific direction during its propagation. Thus, the wave beam steering and focusing has been established, the location of structural damage is done with pulse-echo method by wave propagation. However, the detection accuracy will decrease as side bands energy leakage during wave propagation, so, signals to be generated have to be modified by window tone burst in order to concentrate energy in main bands and minimize the effect of dispersion side bands. In this paper, signals modified by Hanning-windowed tone burst was used to decrease the effect of side bands energy leakage, the results improved the detection accuracy better than signals without window tone burst and show good agreement with theoretical results. Meanwhile, A numerical simulation of aluminium plate demonstrates that phased array antenna technique is feasible in structural damage detection.

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Multi-Location Actuators and Piezoceramic Based 2-D Spiral Array for Structural Health Monitoring: Thin Isotropic Panels

ASME 2010 Conference on Smart Materials, Adaptive Structures and Intelligent Systems, Volume 2 ◽

10.1115/smasis2010-3723 ◽

2010 ◽

Author(s):

Byungseok Yoo ◽

Darryll J. Pines ◽

Ashish S. Purekar

Keyword(s):

Damage Detection ◽

Health Monitoring ◽

Sensor Array ◽

Array Signal Processing ◽

Phased Array ◽

Test Panel ◽

Detection Scheme ◽

Analysis Technique ◽

Spiral Array ◽

Multiple Actuators

In this paper, a new and robust 2-D phased array technique with multiple distributed actuators is studied for damage detection application based on Guided Lamb Wave (GLW) interrogation in a thin isotropic panel. A 2-D phased array technique using a single actuator located near the center of the 2-D phased array is unable to detect a linear crack oriented normal to the wavefront of the GLW excited from the actuator. To overcome this limitation, the 2-D phased array is coupled with multiple actuators in this study where the actuators are positioned at various locations on a test panel while the 2-D phased array is mounted at the center of the panel. A piezoceramic based 2-D phased array with a spiral configuration is used as a sensor array and the corresponding 2-D phased array signal processing is used to produce array responses and detect various damages. An innovative GLW propagation and reflection analysis technique is implemented to evaluate the damage locations in the panel. Experimental results demonstrate that the 2-D phased array damage detection technique using multiple distributed actuators can provide more robust damage detection scheme in thin isotropic panels than a technique with a single actuator element.

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