Consider the one-dimensional thermoelastic problem of a uniform bar constrained in the axial x direction but allowed

Question:

Consider the one-dimensional thermoelastic problem of a uniform bar constrained in the axial x direction but allowed to expand freely in the y and z directions, as shown in the following figure. Taking the reference temperature to be zero, show that the only nonzero stress and strain components are given by:

Ox=-EaT ey = e = a(1 + v)T y X