ABSTRACT
A few other techniques of machinery condition monitoring are followed in industry (Table 12.1). These techniques are generally known as nondestructive test (NDT) techniques. Out of the entire condition monitoring activities carried out in the world, 10% belong to the NDT category. These techniques are usually done for periodic inspections, failure analysis, quality certification, and regulatory compliance. Some of these techniques require skilled and trained personnel to conduct the tests. Many of these tests are conducted in situ with portable NDT units. A few of the commonly used NDT techniques are visual inspection by specialized optical instruments, dye-penetrant test, magnetic particle testing, eddy current testing, radiography, ultrasonics, and acoustic emission.
