Mechanical properties of Materials

Mechanical properties are used to help classify and identify material through their properties. The most common properties are strength, ductility, hardness and Toughness. Most structural materials are anisotropic; it means that their material properties vary with orientation. Mechanical properties occur as a result of the physical properties basic to each material, and are determined through a series of standardized mechanical tests. Some common properties are as following:

Strength:

Strength has several definitions depending on the material type and application. For each material we should know which strength is defined and how is the standard measurement?

Yield Strength:

The yield strength is the minimum stress which produces permanent plastic deformation. It is usually defined at a specific amount of plastic strain, or offset, which may vary by material and or specification. The offset is the amount that the stress-strain curve deviates from the linear elastic line.

Tensile Strength:

Tensile Strength is the maximum stress that a material can withstand while being stretched or pulled before failing or breaking. It calculates by dividing the maximum load on a material experienced during a tensile test by the initial cross section of the test sample.

Ductility:

Ductility is a measure of how much deformation or strain a material can withstand before breaking. The most common measure of ductility is the percentage of change in length of a tensile sample after breaking. This is generally reported as % El or percent elongation.

Toughness:

Toughness is the resistance of materials to fracture. It is often expressed in terms of the amount of energy a material can absorb before fracture. Tough materials can absorb a considerable amount of energy before fracture while brittle materials absorb very little.