##### What is strength of material?

Strength of material is defined as the maximum value of stress that a material can withstand without any failure. Strength is the property of material which doesn’t depend on shape and size of the material.

##### What are the different types of stresses subjected on a material?

Generally a material is subjected by Normal stress and shear stress. Further normal stresses are classified as axial stress, bearing stress and bending stress, whereas shear stresses are classified as direct shear stress and indirect shear stress.

##### What is the difference between strength and stiffness?

Strength is the ability of a part or element of a structure to resist failure whereas stiffness is the ability to resist deformation.

##### What is the nature of stress-strain curve for an ideal brittle material?

For a brittle material, stress-strain curve in tension is a straight line, with failure occurring before any yielding takes place.

##### What is the difference between nominal stress and true stress?

Nominal stress is defined as load divided by the original cross-sectional area of the specimen, whereas true stress is defined as load divided by actual area of cross section.

##### From design point of view, what is the most important property of a material?

Strength of material is the most important property as it enables the material tp resist applied load safely.

##### How is toughness measured?

It is measured in terms of energy required per unit volume of the material, to cause rupture under the action of gradually increasing tensile load.

##### What is complementary shear stress?

Shear stress acted on adjacent and perpendicular faces of an element are equal in magnitude and have direction such that both stresses point towards or point away from the line of intersection of the faces. These shear stresses are called complementary shear stress.

##### What is proof stress?

Some materials like (Al, Cu, Ag) doesn’t show yield point, for such materials, an offset method is used for calculating the design stress. Therefore the stress which is just sufficient to cause a permanent set (elongation) equal to a specified percentage of the original gauge length is known as proof stress.

##### Why rubber is called a brittle material?

Rubber is a brittle material because its post-elastic strain is negligible.

##### What is the value of Poisson’s ratio for most of the metals?

Most of the metals are fall in the range of 0.25 to 0.42.