A steel rod of 320 mm[SUP]2[/SUP] cross sectional area and a coaxial copper tube of 800mm[SUP]2[/SUP] are rigidly fixed together at their ends. An axial compressive load of 40kN is applied to the composite bar and the temperature is raised by 100°C. Determine the stresses in the steel and copper. E copper = 100GPa, E steel = 200GPa, a copper = 16 x 10[SUP]- 6[/SUP] /K and a steel = 12 x 10[SUP]- 6[/SUP] /K1.

 

Consult with your instructor and fellow students. Then, DO YOUR OWN HOMEWORK!!!!

 

Strain=stress/E=change in length/original length is a clue

 

The strains are additive, the strain due to the temperature adds to the strain due to loading.

a) The bars remain the same length as each other

b) the total load on the two bars must equal the applied load

so you have four unknowns: the load in each bar (2), the strain in each bar (2).
you have four equations the constitutive equation for each bar (2) and the equations resulting from a) and b) above.

Four equations, four unknowns. That should cover it.

hey you kids - get off my lawn