Hii all.. I have a question.Suppose there is a cube of side 1m .It is heated by 1°C. The cube is not restrained in any direction. We are required to find out the volumetric strain. I am getting it as 3α. But my question is that since the cube is not restrained , ∴ there should be no stresses in any direction. ∴ εv=(σx +σy+σz)(1-2μ)/E which gives εv=0. plz help..