Mechanical Properties of Materials In strength of Materials

 Plastic Material:

A material which can undergo permanet deformation without rupture is said to be plastic material. The property of the material is known as plasticity. Plasticity is important when material is to to be mechanically formed by causing the material to flow.

Elastic Material:

A material which regains its original size and shape on removal of stress is said to be electic material.

Elatic limit:

The greatest stress that a material can lake without permanent set on the removal of stress is known as elastic limit.

Ductile Material:

A material which can undergo considerable deformation without rupture is said to be ductile material. The major portion of deformation is plastic.

Brittle Material:

A Material which rupture with little or no plastic deformation is said to be brittle material.

Permanent set:

The deformation or strain remaining in a body after removal of stress is known as permanrnt set. This is due to plasic property of material.

Endurance limit:

The greatest stress, applied infinite number of time, that material can take without causing failure is known as endurance or fatigue limit.

Proporttionality limit:

The greatest stress that a material can take without deviation from straight line reletion between stress and strain is known as Proporttionality limit.

Modulus of rupture:

The ultimate strength in flexure tension is known as modulus of rupture.

Modulus of resilience:

The max energy stored per unit volume at the elastic limit is known as modulus of resilience.

Modulus of toughness:

The amount of work required per unit volume to cause failure under static loading is called Modulus of toughness. The toughness of a material is its ability to absorb energy without causing it to break. It is the entire area of stress strain curve upto failure.

Proof stress:

Stress which is just sufficient to cause a permanent set equal to a specfied percentage of the original gauge length.

Plastic strain:

It is dimensional change that occur in a material due to the application of the loads and does not disappear after the removal of the loads.

Elastic strain:

It is the dimensional change that occur in a material due to the application of loads and disappearance completely on the removal of the loads.

Creep:

The long term deflection due to sustained loads.

Factor Of safety:

For Ductile materials F.O.S = yeild stress / working stress.

For Brittle Materials  F.O.S = ultimate stress / working stress.

Ductility and Malleability:

The plastic response of material to tensile force is known as ductility and malleability. The elongation and reduction of area of a tested to failure in tension are generally taken as measure of ductility of material.