Types of testing

Types of Testing: there are two main types of tests:
1. Destructive testing
2. Nondestructive testing
Nondestructive Testing
In certain applications, the evaluation of engineering materials or structures without impairing their properties is very important, such as the quality control of the products, failure analysis or prevention of the engineered systems in service.
This kind of evaluations can be carried out with non destructive test (NDT) methods. It is possible to inspect and/or measure the materials or structures without destroying their surface texture, product integrity and future usefulness. These methods can be performed on metals, plastics, ceramics, composites, cermet, and coatings in order to detect cracks, internal voids, surface cavities, incomplete defective welds and any type of flaw that could lead to premature failure.A general definition of nondestructive testing (NDT) is an examination, test, or evolution performed on any type of test object without changing or altering that object in any way, that can provide useful information regarding the condition of the object being examined, approved procedures are followed, and the examinations are conducted by qualified personnel in order to determine the absence or presence of conditions or discontinuities that may have an effect on the usefulness or serviceability of that object. Nondestructive tests may also be conducted to measure other test object characteristics, such as size; dimension; structure, including alloy content, hardness, grain size, etc.