Method and device for the non-destructive testing of objects using ultrasonics
AssigneeNukem GmbH
InventorsRoman Koch, Thomas Kreutter
Life of this patent
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Abstract
The invention concerns a method and device for nondestructive testing. Ultrasonic pulses are fed into the object under test. Ultrasonic waves emerging from the object are detected by an ultrasonic test head, converted into electrical signal and amplified. The signals are then sampled to produce measurement values, which are digitized and stored. From the digitized sampled values of the signals a function is obtained by interpolation, by means of which the peak values of the ultrasonic waves and/or the time of propagation of the wave at the peak is determined.
Claims7
A method for use in non-destructive testing of objects using ultrasonics, comprising the steps of:
- introducing ultrasonic pulses by an ultrasonic testing head into an object;
- receiving by an ultrasonic testing head ultrasonic waves emitted by the object in response to the ultrasonic pulses and converting the ultrasonic waves into electrical signals having a signal sequence;
- obtaining measurement values from said signals of said signal responses by time-equidistant sampling;
- digitizing and storing said measurement values;
- replacing a function represented by the digitized and stored measurement values by a Grade N polynomial according to the following equation:
- ##EQU16## wherein t.sub.i is the sampling time, for i=0, 1 . . . N, and a.sub.n the coefficients of the polynomial;
- and
- using said polynomial, determining with high resolution an amplitude extreme of the received ultrasonic waves and/or a delay of said ultrasonic wave with an amplitude extreme.
A device for use in non-destructive testing of objects using ultrasonics, comprising:
- an ultrasonic testing head for introducing ultrasonic pulses into an object and for receiving ultrasonic waves emitted by the object in response to the ultrasonic pulses and converting the ultrasonic waves into electrical signals having a signal sequence;
- an amplifier for receiving said electrical signals;
- an analog/digital converter;
- a sample and hold circuit connected between the amplifier and the analog/digital converter and operating with a sampling rate in the range of 60 to 120 MH.sub.z to generate from said electrical signals measurements which are digitized by said analog/digital converter;
- a write/read memory joined to said converter for storing said digitized measurement values;
- and
- a digital processor joined to the write/read memory for processing the stored digitized measurement values to replace said values by a Grade N polynomial according to the following equation:
- ##EQU19## wherein t.sub.i is the sampling time, for i=0, 1 . . . N, and a.sub.n the coefficients of the polynomial;
- and for using said polynomial to determine an amplitude extreme of the received ultrasonic waves and/or a delay of said ultrasonic wave with an amplitude extreme.
Dependencies are inferred from the claim text.