DEVELOPMENT OF NONDESTRUCTIVE INSPECTION METHODS FOR COMPOSITE REPAIR

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Della Harris
5 years ago
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1 DEVELOPMENT OF NONDESTRUCTIVE INSPECTION METHODS FOR COMPOSITE REPAIR

FIGURE nondestructive imaging, imaging, panel panel was was FIGURE 1.1. Composite Composite repair repair test test panel panel used used in in study. study. After After nondestructive sectioned of interior.

2 FIGURE nondestructive imaging, imaging, panel panel was was FIGURE 1.1. Composite Composite repair repair test test panel panel used used in in study. study. After After nondestructive sectioned of interior. interior. sectioned along along vertical vertical line line for for microscopic microscopic examination examination of COMPUTER REPAIR COMPUTER AIDED AIDED TAP TAP TEST TEST (CATT) (CATT) FOR FOR COMPOSITE COMPOSITE REPAIR The quantitative quantitative The CATT CATT isis an an instrumented instrumented tap tap test test system system developed developed for for evaluation and imaging of composite structures [1,2]. The system consists of three three evaluation and imaging of composite structures [1,2]. The system consists of components: electronic electronic circuitry circuitry for for components: magnetic magnetic cart cart for for mechanized mechanized tapping, tapping, acquiring and software software for for displaying, displaying, acquiring and and processing processing accelerometer accelerometer signal, signal, and analyzing, PC. The The mass mass that that taps taps on on surface surface of of aa analyzing, and and storing storing test test results results in in aa laptop laptop PC. part Using repulsive repulsive force force part isis an an accelerometer accelerometer fitted fitted with with aa hemispherical hemispherical steel steel tip. tip. Using between wheel and and aa magnet magnet in in between strong strong permanent permanent magnets magnets embedded embedded in in aa wheel accelerometer up and and down down as as cart cart isis accelerometer frame, frame, magnetic magnetic cart cart drives drives accelerometer accelerometer up moved output of of accelerometer accelerometer isis moved across across surface surface by by hand hand [5]. [5]. The The voltage voltage output conditioned interface, where where conditioned by by electronic electronic circuit circuit in in accelerometer-computer accelerometer-computer interface, "contact time is is duration duration "contact time" time" is is measured measured and and converted converted into into digital digital data. data. The The contact contact time when surface. For For most most composite composite parts parts found found when accelerometer accelerometer tip is in contact with surface. on aircraft, aircraft, contact contact time typically ranges from from 200 to 1000 microseconds on microseconds for for an an accelerometer mass mass of of order of 20 grams. Damages and defects accelerometer defects lower lower local local stiffness of of part and hence lengn contact stiffness contact time. time. The The scan scan data, data, in in form form of of contact time time versus versus position, are displayed on computer screen contact screen while while scanning. scanning. Damaged regions regions appear appear as areas of anomalously high contact Damaged contact time as as compared compared to to surrounding. Based Based on on aa simple simple spring model, local stiffness stiffness can be surrounding. be deduced deduced from from contact time time and and accelerometer accelerometer mass. It had been demonstrated contact demonstrated previously previously that that stiffness deduced deduced from from tap test agreed well with stiffness stiffness stiffness measured measured directly directly in in static static load tests tests for for a variety of composites [6]. load 1020

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4 FIGURE

5 FIGURE 4. Sectioned view of repair panel. A comparison

6 FIGURE 6. Comparison between air-coupled UT image and interior of repair. CONCLUSIONS It was demonstrated that both computer aided tap test and air-coupled ultrasonic scan were able

7 2. Peters, J, Barnard, D, Hudelson, N, Simpson, T, Hsu, D, 2000, "A prototype tap testing imaging system: Initial field test results," Rev. Prog. Quantitative NDE, Vol. 19, eds. D. O. Thompson and D. E. Chimenti, Amer. Inst. Phys. Melville, New York. pp Bhardwaj,

Application of portable modules for fatigue crack characterization

Application of portable modules for fatigue crack characterization Igor N. Komsky * Northwestern University ABSTRACT This paper is dealing with the ultrasonic imaging techniques and instrumentation that