Corrosion rate monitoring using ultrasound, and associated systems and methods

1. A method for measuring a rate of corrosion progress in a specimen, comprising:

generating a first initial pulse into the specimen by an ultrasonic transmitter;

acquiring a first reflected waveform from the specimen by an ultrasonic receiver, wherein the first reflected waveform includes a first reflection of the first waveform and a second reflection of the first waveform;

generating a second initial pulse into the specimen by the ultrasonic transmitter, wherein the first initial pulse and the second initial pulse are separated by a time period;

acquiring a second reflected waveform from the specimen by the ultrasonic receiver, wherein the second reflected waveform includes a first reflection of the second waveform and a second reflection of the second waveform; and

determining the rate of corrosion by:

fitting a first continuous curve through discrete points of the first reflection of the first waveform;

fitting a second continuous curve through discrete points of the first reflection of the second waveform;

aligning the first reflection of the first waveform and the first reflection of the second waveform based on aligning the first curve and the second curve,

determining a time difference between the second reflection of the first waveform and the second reflection of the second waveform, and

based on the time difference, determining the rate of corrosion progress using a speed of ultrasound through the specimen.

2. The method of claim 1 , wherein the ultrasonic transmitter comprises a delay line.

3. The method of claim 2 , wherein the first reflection of the first waveform and the first reflection of the second waveform are first reflections from the delay line.

4. The method of claim 3 , wherein the second reflection of the first waveform and the second reflection of the second waveform are first reflections from a back wall of the specimen.

5. The method of claim 2 , wherein the first reflection of the first waveform and the first reflection of the second waveform are first reflections from a back wall of the specimen.

6. The method of claim 5 , wherein the second reflection of the first waveform and the second reflection of the second waveform are second reflections from a back wall of the specimen.

7. The method of claim 2 , wherein the first curve and the second curve are selected from a group consisting of a polynomial and a spline.

8. The method of claim 2 , wherein the first reflected waveform and the second reflected waveform are acquired at a first sampling frequency, the method further comprising:

resampling the first curve and the second curve at a second sampling frequency that is higher than the first sampling frequency; and

aligning the first reflection of the first waveform and the first reflection of the second waveform based on additional discrete points obtained by the second sampling frequency.

9. The method of claim 2 , further comprising:

cross-correlating the first curve and the second curve;

identifying a maximum of a cross-correlation between the first curve and the second curve; and

aligning the first reflection of the first waveform and the first reflection of the second waveform at least in part based on the maximum of the cross-correlation.

10. The method of claim 1 , wherein aligning the first reflection of the first waveform and the first reflection of the second waveform is based on aligning a maximum of the first reflection of the first waveform and a maximum of the first reflection of the second waveform.

11. The method of claim 1 , wherein aligning the first reflection of the first waveform and the first reflection of the second waveform comprises superimposing the first reflection of the first waveform and the first reflection of the second waveform over each other when the first waveform and the second waveform are displayed visually.

12. The method of claim 1 , further comprising:

generating additional initial pulses into the specimen by the ultrasonic transmitter;

acquiring additional reflected waveforms from the specimen; and

averaging the additional multiple waveforms to produce averaged first reflected waveform and averaged second reflected waveform.

13. The method of claim 1 , wherein the time period is less than one month.

14. The method of claim 1 , further comprising:

measuring a first temperature of the specimen corresponding to the first reflected waveform from the specimen;

measuring a second temperature of the specimen corresponding to the second reflected waveform from the specimen; and

determining the rate of corrosion based at least in part on a difference between the first temperature and the second temperature.

15. A non-transitory computer readable medium having computer-executable instructions stored thereon that, in response to execution by one or more processors of a computing device, cause the computing device to perform actions comprising:

generating a first initial pulse into the specimen by an ultrasonic transmitter comprising a delay line;

acquiring a first reflected waveform from the specimen by an ultrasonic receiver, wherein the first reflected waveform includes a first reflection of the first waveform and a second reflection of the first waveform;

generating a second initial pulse into the specimen by the ultrasonic transmitter, wherein the first initial pulse and the second initial pulse are separated by a time period;

acquiring a second reflected waveform from the specimen by the ultrasonic receiver, wherein the second reflected waveform includes a first reflection of the second waveform and a second reflection of the second waveform; and

determining the rate of corrosion by:

fitting a first continuous curve through discrete points of the first reflection of the first waveform;

fitting a second continuous curve through discrete points of the first reflection of the second waveform;

aligning the first reflection of the first waveform and the first reflection of the second waveform based on aligning the first curve and the second curve,

determining a time difference between the second reflection of the first waveform and the second reflection of the second waveform, and

based on the time difference, determining the rate of corrosion progress using a speed of ultrasound through the specimen.

16. The non-transitory computer readable medium of claim 15 , wherein the first reflection of the first waveform and the first reflection of the second waveform are first reflections from the delay line.

17. The non-transitory computer readable medium of claim 16 , wherein the second reflection of the first waveform and the second reflection of the second waveform are first reflections from a back wall of the specimen.

18. The non-transitory computer readable medium of claim 15 , wherein the actions further comprise:

generating additional initial pulses into the specimen by the transducer transmitter;

acquiring additional reflected waveforms from the specimen; and

averaging the additional multiple waveforms to produce averaged first reflected waveform and averaged second reflected waveform.

19. The non-transitory computer readable medium of claim 15 , wherein the actions further comprise:

cross-correlating the first curve and the second curve; and

identifying a maximum of a cross-correlation between the first curve and the second curve,

wherein aligning the first reflection of the first waveform and the first reflection of the second waveform is based at least in part on the maximum of the cross-correlation.