Any type of testing performed on an object that leaves it unchanged.

Testing of the condition or quality of a material by a means which does not damage or alter the sample. Generally performed using electronic means.

(NDT) a procedure for determining the quality or characteristics of a material, part, or assembly without permanently altering it or its properties; examples include ultrasonic and radiographic inspection.

Testing or inspection that does not destroy the object being tested or inspected.

Broadly considered synonymous with nondestructive inspection (NDI).

Nondestructive testing (NDT), also called nondestructive evaluation (NDE) and nondestructive inspection (NDI), is testing that does not destroy the test object. NDE is vital for constructing and maintaining all types of components and structures. To detect different defects such as cracking and corrosion, there are different methods of testing available, such as X-ray (where cracks show up on the film) and ultrasound (where cracks show up as an echo blip on the screen).