1. The problem statement, all variables and given/known data Problem number 3 is the one I have the issue with. I attached it as a PDF file. 2. Relevant equations Looking through my textbook, the equations that I think are relevant are: P=Eδ/2b[((c^2-b^2)(b^2-a^2)/(2b^2(c^2-a^2))] I am assuming the hub and the pipe are the same material σ=p((c^2+b^2)/(c^2-b^2)) this is for the tensile at the inner surface in the tangential direction δ=(2bp/E)[(c^2+b^2)/(c^2-b^2)+v] I understand the cyclic loading part, I just don't follow what to do with the two interferences. 3. The attempt at a solution I feel I would be able to work out a solution to this problem if I knew the right direction to go in. I know how to handle interference fits, but I do not know if this problem is solvable without the thickness of the pipe.