Detection of water ingress in composite sandwich structures: a magnetic resonance approach

LaPlante, Gabriel; Marble, Andrew E.; MacMillan, Bryce; Lee‐Sullivan, Pearl; Colpitts, Bruce G.; Balcom, Bruce J.

doi:10.1016/j.ndteint.2005.01.006

Cited by 32 publications

(36 citation statements)

References 10 publications

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“…This yields a straightforward analytical result which can serve as a building block for more complex optimizations. (4) Note that if c11 had been set to zero instead of b1, the expression for the field here would be identical but y-directed. Differentiating Eq.…”

Section: Optimizationmentioning

confidence: 99%

“…To this end, a number of methods have been proposed, including ultrasound inspection, radiography, and infrared thermometry. The relative merits of these methods [4]. Potential drawbacks of these more traditional techniques include accuracy, cost, and safety.…”

Section: Introductionmentioning

confidence: 99%

“…New inspection techniques are currently being sought. Candidate technologies include dielectric methods [5], electrochemical impedance testing [6], and nuclear magnetic resonance (MR) [4,7]-the focus of this work.…”

Section: Introductionmentioning

confidence: 99%

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A Unilateral Magnetic Resonance Moisture Sensor for Aerospace Composites

Marble

LaPlante

Mastikhin

et al. 2006

2006 Canadian Conference on Electrical and Computer Engineering

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Magnetic resonance (MR) is a proven, nondestructive analytical technique in chemistry and medicine. The sensitivity of a MR experiment is principally dependent on the strength and homogeneity of a polarizing static magnetic field, termed Bo. This requirement has traditionally limited MR experiments to a 'closed' configuration of magnets or wires generating a highly uniform Bo, but limiting the size of the sample that can be investigated To remove this size requirement, 'open' or unilateral sensors have been developed, in which a planar arrangement of magnets generates a suitable Bo at a location displaced from the sensor. This configuration increases the range of samples that can be examined, at the expense of Bo homogeneity. This paper presents the design of a portable, unilateral MR sensor suitable for nondestructive moisture detection. The sensor comprises an array of permanent magnets, designed using an inversion approach in which a target magnetic field is specified in a volume over the array. Using an analytical optimization, the magnet sizes, strengths, and positions are then determined to give the target field The result is a large region offield homogeneity, displaced -4.5cm from the array, suitable for MR. The sensor is demonstrated for the in situ detection of moisture within aircraft composites. The paper discusses the design and construction of the magnet array, andpresents results ofsuccessful moisture detection.

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Section: Optimizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Unilateral Magnetic Resonance Moisture Sensor for Aerospace Composites

Marble

LaPlante

Mastikhin

et al. 2006

2006 Canadian Conference on Electrical and Computer Engineering

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“…5 A number of interesting applications have been demonstrated, including determination of fat content in live Atlantic salmon, 6 one-dimensional imaging of heterogeneous rubbers, 7 characterisation of polymer materials, 8 self-diffusion measurements, 9 tendon anisotropy studies 10 and detection of water ingress in model aerospace composites. 11 Unilateral NMR has other advantages over a traditional benchtop time domain NMR. With unilateral NMR it is possible to measure whole packed products, the permanent gradient of the magnet can be controlled to suit a particular application and the low weight of the magnet makes unilateral NMR systems generally portable.…”

Section: Introductionmentioning

confidence: 99%

Rapid determination of the fat content in packaged dairy products by unilateral NMR

et al. 2008

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BACKGROUND: Knowledge of the fat content in dairy products is important for both industry and consumers. A new procedure for rapid and non-destructive determination of the fat content in dairy products using unilateral nuclear magnetic resonance (NMR) is proposed. The sample magnetisation is prepared using either T 1 suppression or diffusion editing, and read out via a Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence.

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“…In our study, we sealed off the edges of the honeycomb core panels so that the water is absorbed from the laminate skin. NDI techniques such as capacitance or magnetic resonance methods are usually applied to the honeycomb sandwich material to detect moisture ingression [4][5][6][7][8]. Ultrasonic techniques are reported to produce unreliable results for the moisture absorption in the sandwich structures.…”

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confidence: 99%

Investigations of moisture ingressions in composites via NDI techniques

2014

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Moisture ingression creates huge concerns on fiber reinforced composites because of the reduction in mechanical strengths with the moisture absorption and additional weight gains on the aircraft. If the appropriate techniques are used to predict the moisture ingression in the laminate composite structures, it will be of an immense advantage to detect moisture contents and their effects on the properties of the composites. Mechanisms of moisture influence in the composite structures also need to be thoroughly understood for a better design of new structural composites. This research study aims at investigating the effectiveness of different non-destructive inspection (NDI) techniques to detect moisture absorption. Carbon and glass fiber reinforced composite panels were prepared and used during the moisture ingression tests. Different NDI techniques, including ultrasonic through transmission and pulse echo, phase array, bondmaster and digital tap hammer were chosen to determine the moisture ingression levels. Throughout the tests, initial and final weights of the composite panels were determined using the high accuracy balances. NDI scanning parameters were kept constant for the tests. The effectiveness of each technique was determined and their results were discussed in detail.

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Detection of water ingress in composite sandwich structures: a magnetic resonance approach

Cited by 32 publications

References 10 publications

A Unilateral Magnetic Resonance Moisture Sensor for Aerospace Composites

A Unilateral Magnetic Resonance Moisture Sensor for Aerospace Composites

Rapid determination of the fat content in packaged dairy products by unilateral NMR

Investigations of moisture ingressions in composites via NDI techniques

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