Determine elongation of bar:

A conical bar tapers uniformly from diameter of 4 cm to 1.5 cm in length of 40 cm. If axial force of 80 kN is applied at each end, determine elongation of bar. Take E = 2 × 105  N/mm²                

Sol.: Given; P = 80 × 103  N,

E = 200GPa = 2 × 10⁵  N/mm², dL = 40mm, d₂  = 15mm, L = 400mm

As;

By putting all the value, we get

δL = [4 × 80 × 10³  × 400]/[Π(2 × 10⁵) × (40 × 15)]

= 0.3397mm                                                                            .......ANS