Recent content by itsmi

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    Bending stiffness of circular bars

    You keep saying it is different, but you still haven't given any explanation or good reason, despite me asking multiple times. As I said, I did the calculation and get the same results. It doesn't matter if it's a three point bending or cantilever beam with a point load. Is there anyone else...
  2. I

    Bending stiffness of circular bars

    Anyone else?
  3. I

    Bending stiffness of circular bars

    Ok, so here's my procedure I: Second moments of area, which directly relate to the stiffness R: Radius of big rod and outer radius of tube r: radius of small rod and inner radius of tube ROD IbigRod = pi/4*R4 ROD + SHELL IRodAndTube = IsmallRod + Ishell = pi/4*r4 + pi/4*(R4-r4) = pi/4*R4...
  4. I

    Bending stiffness of circular bars

    Thank you for the quick response. I'm aware that this is the tricky part. But the question is: Will it move (relatively to the rod)? I don't think it will. How would you approach this problem mathematically, rather than using your intuition?
  5. I

    Bending stiffness of circular bars

    Which of the two is stiffer in bending? 1. A circular rod of diameter D and length L. 2. A circular rod of diameter d and length L, surrounded by a tube of inner diameter d, outer diameter D, and length L. The tube is not bonded and can freely move. It seems like an easy solution in that we...