Mechanical Properties of Solids

Stress is the restoring force per

Stress is the restoring force per unit area developed inside a body when it is deformed. Its magnitude is F/A, where F is the force applied normal to

Strain is the fractional change

Strain is the fractional change in dimension produced by stress. Longitudinal strain = ΔL/L, shearing strain = Δx/L = tan θ, and volume strain = ΔV/V.

For small deformations

For small deformations, stress is proportional to strain: stress = k × strain. This law is empirical and is valid only in the linear part of the stres

A typical metal shows a linear

A typical metal shows a linear elastic region from O to A where Hooke's law is obeyed. From A to B, stress and strain are not proportional but the bod

Young's modulus Y is the ratio

Young's modulus Y is the ratio of tensile or compressive stress to longitudinal strain: Y = σ/ε = (F/A)/(ΔL/L) = (F × L)/(A × ΔL). Its unit is the sam