Imagine you have a cylindrical plug of plastic that you press fit into a hole. I need to determine the raidal pressure, radial stress, that the plug exerts on the wall of the cylinder. Here is what I have so far. Lateral Strain = (d_initial - d_final) / d_initial\ From what I understand the Young's modulus deals with axial stress and axial strain. I can use Possion's ratio to determine the axial strain given my lateral strain but I'm not sure how to go from this to radial stress. Basically if I have a rod that changes diameters by x ammount, what radial pressure is required to do this. Thanks for the help!