Dipl. Phys. Michael Berke
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Even the commonly used flaw evaluation methods can be considerably simplified by the use of microprocessor controlled ultrasonic instruments. This results in advantages such as saving of time and increased test reliability.
In nondestructive ultrasonic testing of materials, high frequency sound pulses (approx. 1 to 10 MHz) are beamed into the workpiece to be tested by means of a probe. The sound is reflected from internal non homogeneities, e.g. a flaw in the material. These sound reflections are again received by the probe and processed in the ultrasonic instrument. This is followed by the evaluation of the signals (echoes), viz. with the standard methods on the basis of acoustic time of flight and amplitude.
|Refernce block methode||DGS-method||Pros||The DAC curve contains all test-related|
Influences, i.e. no time-consuming
corrections are recuired.
Easy and reliable evaluation.
|No reference blocks required.||Cons||Fabrication or procurement of a|
suitable reference block.
Recording of a DAC curve for every
|Measurement and consideration of different|
Graphic determination of the equivalent reflector size.