Thermal Expansion: How do you calculate reaction forces due to it?

Question

Give that the change in length due to a temperature change is delta = alpha * (delta Temp) * length, and a multibar system that fits perfectly between two rigid walls, how do you calculate the reaction forces from the compatibility equations?

Answer 1

The reaction force should be equal to the force needed to compress the free bar to fit back between the walls. So, the thermal expansion delta is the strain, multiplied by the modulus will give you the stress. The reaction force is simply the stress multiplied by the area.