Question

Three vertical wires, one of steel and two of aluminium, are suspended in the same vertical plane from a horizontal support. They are all of same length and same area of cross-section and carry a load by means of a rigid cross bar at their ends. The load is increased and the temperature is changed in such a way that the stress in each wire is increased by 15N/mm². Find the change in temperature. 

E_S = 3E_A = 210kN/mm², α_S = 11 × 10⁻⁶/°C, α_a = 22 × 10⁻⁶/°C

Answer 1

There will be a direct stress and a temperature stress in each wire. Force due to temperature stresses are balanced; therefore, Say A is area of cross-section of each wire