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1 Learn the meaning of the following words and word-combinations word groups:

to evaluate the properties, without causing damage, troubleshooting and research, remote
visual inspection (RVI), eddy-current testing, to examine external surfaces in detail,
transparent, penetrating electromagnetic radiation, to penetrate fatigue cracks, eddy current, to
design the best set of parameters, to confirm the specified welding parameter, sets of
differential equations, to derive, the structure undergoes a dynamic input, tap of a hammer or
a controlled impulse, displacement or acceleration at different points of the structure,
corresponding output, to rupture.

2 Read and translate text:
Nondestructive testing

Non-destructive testing (NDT) is a wide group of analysis techniques used in science and
industry to evaluate the properties of a material, component or system without causing
damage. The terms Nondestructive examination (NDE), Nondestructive inspection (NDI) and
Nondestructive evaluation (NDE) are also commonly used to describe this technology.
Because NDT does not permanently alter the article being inspected, it is a highly valuable
technique that can save both money and time in product evaluation, troubleshooting, and
research. Common NDT methods include ultrasonic, magnetic-particle, liquid penetrant,
radiographic, remote visual inspection (RVI), eddy-current testing, and low coherence
interferometry. NDT is a commonly used in forensic engineering, metallurgical and materials
engineering mechanical engineering, electrical engineering, civil engineering, systems
engineering, aeronautical engineering, medicine, and art.

Methods
NDT methods may rely upon use of electromagnetic radiation, sound, and inherent
properties of materials to examine samples. This includes some kinds of microscopy to
examine external surfaces in detail, although sample preparation techniques for
metallography, optical microscopy and electron microscopy are generally destructive as the
surfaces must be made smooth through polishing or the sample must be electron transparent
in thickness. The inside of a sample can be examined with penetrating electromagnetic
radiation, such as X-rays or 3D X-rays for volumetric inspection. Sound waves are utilized in
the case of ultrasonic testing. Contrast between a defect and the bulk of the sample may be
enhanced for visual examination by the unaided eye by using liquids to penetrate fatigue
cracks. One method (liquid penetrant testing) involves using dyes, fluorescent or non-
fluorescing, in fluids for non-magnetic materials, usually metals. Another commonly used
method for magnetic materials involves using a liquid suspension of fine iron particles
applied to a part while it is in an externally applied magnetic field (magnetic-particle testing).
Thermoelectric effect (or use of the Seebeck effect) uses thermal properties of an alloy to
quickly and easily characterize many alloys. The chemical test, or chemical spot test method,
utilizes application of sensitive chemicals that can indicate the presence of individual alloying
elements. Electrochemical methods, such as electrochemical fatigue crack sensors, utilize the
tendency of metal structural material to oxidize readily in order to detect progressive damage.

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