Mechanical Properties 2

MECHANICAL PROPERTIES

2

Compression Testing

Durometer:

-Used to measure the hardness of soft elastic material such as rubber ie: bicycle tire.

-Measures a materials resistance to plastic deformation with a conical spring steel indenter connected to a scale.

Brunell Test:

-Uses Tungsten Corbid or 10mm Steel ball to leave a small indentation on a material by applying a specific force.

-A measurement of the indentation will determine the hardness of the material.

Rockwells Test:

-Uses a Diamond tipped cone or small steel ball as indenter.

-A specific force is applied and the indenter penetrates the material leaving an indentation to be measured.

-Measures the hardness of a material.

A Compression test is used to determine the compressive force or resistance of a material when subjected to loads.

Vickers Test:

-Uses square based diamond tipped pyramid as indenter.

-Procedure simular to Brunell test.

-Uses loads between 1kg-120kg.

-Measures the hadness of a material.

-2 step testing process.

-Mostly used on Steel or Iron.

-Would not be suitable for soft materials.

-This is a 1 step direct reading test.

-Can do 300 test per hour.

-Least accurate test of the 3 mentioned.(brunell,vickers,rockwells)

-2 step test.

-Test is done on location.

-Suitable for thin materials.

-Not as accurate as Brunell test on metals.

-Square diamond indenter is easy to read.

Impact Testing

Charpy Test:

-Measures a materials toughness and load baring abilities.

-Uses a pendulum to subject a specimen to a force/load.

-Specimen is typically a small piece of steel with a U or V shaped notch machined into its side allowing it to break when hit.

Izod Test:

-Uses pendulum the Procedure is simular to Charpy test.

-Strikes an unsupported specimen that is placed in a verticle position.

-Specimen is also small piece of steel with U or V shaped notch

Impact Test:

-Uses pendulum.

-Specimen is clamped to a cross head and the test fixture.

-When struck the specimen is pulled apart by the force.

-This test is conducted at a variety of temperatures.

Impact testing uses a sudden dynamic force to test a materials toughness and resistance to fracture.

Rapid Loading And Unloading:

-Materials are subjected to cycles of loading and unloading of a force until it breaks.

-This happens because he material fatigues then factures.

-90% of metallic fracture occurs because of fatigue.

-The R.R. Moore testing system is used to conduct this procedure.

Shear Test:

The shear test tell us the strength of a material by subjecting it to forces parallel to its side until it fractures.​​​​​​ ie: reinforced concrete pillars.