Question

The surface defects in polymeric materials can be detected using eddy

current testing. Do you agree with this statement?

a) Yes

b) Maybe

c) No
​

Answer 1

Answer:

Yes

Explanation:

Eddy-Current Testing

EC methods permit the determination of textural parameters like layer orientation and gap sizes between roving, the detection of foreign polymer particles. Eddy current testing by inductive sensors is an important NDE technique, especially for layered structures. The penetration depth of the electromagnetic excitation wave, the so-called skin depth, µd0=1/psµf, restricts the depth at which flaws can be found. For a plane wave excitation with frequency f of a medium with conductivity s and permeability µ, d0 denotes the depth of material where the amplitude is attenuated by 1/e and the phase is rotated by 1 rad. Thus, the phase lag of the response signal contains information about the flaw depth. In contrast to conventional techniques, SQUID systems offer a high sensitivity at low excitation frequencies, permitting the detection of deeper flaws, and a high linearity, allowing quantitative evaluation of magnetic field maps from the structure investigated.