If the length is increased from its natural length then it is known as tensile strain. (ii) Compressive strain: If the length is decreased from its natural length then it is known as compressive strain. ( ) Shearing strain Consider a cuboid as shown in Figure . .
Let us assume that the body remains in translational and rotational equilibrium. Let us apply the tangential force F along AD such that the cuboid deforms as shown in Figure . . Hence, shearing strain or shear is (ε s ) Figure .
Shearing strain a' a B C x d' d x h A' D D' h b θ θ c F ε s = AA BA x h ′ = = tan θ ( . ) For small angle, tanθ ≈ θ Therefore, shearing strain or shear, ε s = x h = θ Angle of shear ( ) Volume strain If the body is subjected to a volume stress, the volume will change. Let V be the original volume of the body before stress and V + ∆ V be the change in volume due to stress. The volume strain which measures the fractional change in volume is Volume strain, ε v = D V V ( .
) Elastic Limit The maximum stress within which the body regains its original size and shape after the (ii) Volume stress This happens when a body is acted by forces everywhere on the surface such that the force at any point is normal to the surface and the magnitude of the force on a small surface area is proportional to the area. For instance, when a solid is immersed in a fluid, the pressure at the location of the solid is P, the force on any area ∆ A is F = P ∆A Where, F is perpendicular to the area. Thus, force per unit area is called volume stress. σ v F which is the same as the pressure.
(b) Strain: Strain measures how much an object is stretched or deformed when a force is applied. Strain deals with the fractional change in the size of