Mechanical Property 

Definition 

Strength

The ability to withstand force without breaking or permanently bending.

Bending Strength

The ability to remain rigid and withstand deformation when subject to a force. 

Compressive Strength

The ability to withstand pushing forces which attempt to crush or shorten the material

Tensile Strength

The ability to resist stretching or pulling forces

The amount of energy required to bend a material= tensile strength.

Shear Strength

The ability to resist sliding forces acting against each other.

Torsional Strength 

The ability to withstand twisting forces under tension or torque (twisting force).

Plasticity

The ability to be permanently changed in shape by an external force without cracking. e.g. hammer blows or pressure (metals and thermoplastic polymers are generally more plastic when heated.)

Malleability 

The ability to be formed (worked, hammered, stretched, shaped, rolled) with the application of force

(malleability increases with a rise in temperature e.g: metals and polymers)

Ductility 

The ability to be drawn out. (can be deformed under pressure before cracking)

Ductility decreases with temperature, so these materials are weaker at higher temperatures.

Elasticity 

The ability to flex and bend when a force is applied and regain original/ normal shape when force is removed. 

Impact Resistance (toughness)

The ability to withstand sudden impact without fracture.

It can also refer to a materials ability to withstand bending. 

(A tough material could be bent many times before it snaps the opposite would be brittle- snaps easily when bent)

Hardness

The ability to withstand abrasive wear (scratches) and indentation. 

Durability

The ability to withstand wear and tear, weathering and the deterioration or corrosion this may cause.

Weathering can change the appearance of a material and result in mechanical weakening.

Fatigue resistance

The ability to withstand alternating stresses over a long period of time without fracture (eg. living hinge on polypropylene)

Stiffness

Stiffness is the rigidity of an object — the extent to which it resists deformation in response to an applied force. The complementary concept is flexibility or pliability: the more flexible an object is, the less stiff it is.

Rigidity

The ability for a material to resist bending, stretching, twisting or other deformation under a load