In the field of industrial nondestructive testing similar to that when people buy watermelon "at Paper guess melon." Buy watermelon, watermelon by hand gently stroking the jacket, listening to sounds or touch with, and would like to guess what the raw and cooked watermelon, which is often the habit of the people. If the suspect is in doubt, then checked the incision requirements.
Pat hand, the watermelon is no damage, and non-destructive, listen to sound or feel guess watermelon with raw and cooked, "at Paper guess melon," This is life "nondestructive testing" and "cut-see Is "This is the life of a destructive inspection. Regardless of how NDT technology development, "at Paper guess melon" thrust connotation unchanged; on the test results (guess) there is doubt, to anatomy (incision) certification, the basic idea is unchanged.
Ancient and simple NDT methods, such as percussion instruments, listen to the sound, to identify cracks, and so there is still used; but their location and size of defects, and can not make the "basic line" judge, and not be regarded as The NDT methods. Only technical NDT methods can guarantee the accuracy of the results as mentioned above, and repeatability. Usually the nondestructive testing techniques that ultrasonic testing (UT)…… and so on.

Nondestructive Testing: Nondestructive Testing (NDT initials).
Nondestructive Testing: failure to destroy the premise, or macro-defect inspection workpiece measurement characteristics of the various parts of the methods referred to.
NDT: macro defect detection workpiece NDT.