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Preparatory Notes for ASNT NDT Level III Examination - Ultrasonic Testing, UT

Preparatory Notes for ASNT NDT Level III Examination - Ultrasonic Testing

Preparatory Notes for ASNT NDT Level III Examination - Ultrasonic Testing

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Application Case#1:<br />

The specimen's geometry determines the number of its natural frequencies: a<br />

rod has few whilst a complex work-piece has many such frequencies.<br />

Typically, the in<strong>for</strong>mation that can be obtained by acoustic resonance<br />

analysis includes cracks, structural properties, cavities, layer separation,<br />

chipping, density fluctuations etc. Damping behaviour depends firstly on the<br />

material, and secondly, on how the specimen is positioned during its<br />

excitation. In order to achieve high frequency resolution, signal duration<br />

("ringing duration") should be as long as possible (> 50 ms).

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