Materials Testing

Materials science, also known as materials engineering is one of the important subjects of any field of engineering especially mechanical engineering. When you study materials science, material testing is an important topic that a mechanical engineering student should learn because commonly, mechanical engineers are the ones who test materials before using them.

Why a material needs to be tested

Before a material or specimen is used on its function, a series of tests are being made to prove that it is on its proper conditions and to ensure safety. Common properties of materials being tested include hardness, tensile and compression strength, break load, shear and bearing strength, ductility, elastic limit, Young’s modulus, elongation, rupture strength, modulus of elasticity and rigidity,  and tear resistance. In the field of mechanical engineering, metals are the mostly used and therefore, the most commonly tested as well. In some other areas such as civil engineering, concretes, roads, and structures are also being tested before using them.

Common types of material testing in mechanical engineering

Metals are the materials being often used for designing machines and other mechanical tools. In testing materials, there are two major types being used: destructive and non-destructive testing.

A. Destructive testing – this test aims to bring out the material’s failure under a certain load. This type of test is easier to analyze than non-destructive testing, but a bit more costly because it damages the specimen partially or completely. The following are the most typical types of destructive testing used in mechanical engineering field.

• Hardness test – this type of test is used to measure the material’s resistance to indentation over a specific period. Brinell hardness test is the most common type of hardness test. Rockwell, Vickers and Shore Sclerospcope are also used. 
• Stress test – this test is used to measure the constancy and stability of a given specimen and system.
• Impact test – this test is used to determine the amount the energy absorbed by the material up to its fracture state at a high velocity. 
• Crash test – this test is commonly used on automobiles which aims to determine the ability of the material when being crashed over a given time and speed.

B. Non-destructive test – this test is commonly used in testing larger specimen such as roads, dams, bridges, and infrastructures. These large specimens cost high and subjecting them into destructive testing is somewhat more costly. Except for the buildings that are established in earthquake zones, these buildings are often tested on how well it can withstand earthquake. But aside from those, non-destructive are typically used. Common non-destructive tests include ultra-sonic, Eddy current testing, liquid penetrate and radiographic analysis.