General Mechanical

General Mechanical

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Spreader Lifting Beam Hand Calculation

    • mmh.rakin
      Subscriber

      Hi, Can anyone help to calculate bendling stress and delection for the spreader beam. M and P has equal load of 200KN. Lifting chain at N and O creates 30 degree angle with vertical.

      Simulated in Ansys, need to validate agains hand calculation. Tried bending stress calculation, it's too less to the equivalent stress. Please share your concern and appriate formula for the hand calculation.

    • peteroznewman
      Subscriber

      It helps if you show a coordinate system on your figure.  Let's assume X is horizontal and Y is vertical with the origin at the center as you show. Draw a rectangle in SpaceClaim of the right half of the bar, since the loads and geometry are symmetric. Draw two small circles to apply the load and support. You only need that surface and will assign the 13 mm thickness in Mechanical.  You don't say what the material is, but Young's Modulus and Poisson's Ratio is required to calculate a stress.

      In Mechanical, insert Symmetry into the model, insert a Symmetry Region and select the left edge of the rectangle. Create a Csys at the center of the support hole, then edit the Csys by rotating it 30 degrees about Z so the Y axis points along the lift chain. Create a Remote Displacement and select the edge of the support hole. Select the 30 degree Csys in the Remote Displacement then set the Y axis to 0 displacement, set the Z axis to 0 displacement, leaving the other four Free.  Now you can apply a Force of 200 kN to the edge of the load bearing hole.

      This should solve, though the body has no constraint on rotation about global X, but the fact that the support is above the load means the body is stable. If necessary, another constraint could be added, or weak springs could be used to get this to solve.

    • mmh.rakin
      Subscriber

      Hi, thank you for your nice and kind reply. I need help about hand calcuations. How to calculate benign stress and deflection for this beam?

    • Harshvardhan
      Ansys Employee

      Hi,
      You can use Macaulay's Method for hand calculations. There are a lot of tutorials avaialble in YouTube and other free platforms for it.

      I hope this helps.

      Regards,
      Harshvardhan
      Ansys Help
      Ansys Learning Forum (Rules & Guidelines)

      • Harshvardhan
        Ansys Employee

        Please note that this is not a hand calculation method that Ansys recommends. This is simply the go-to hand calculation method I personally use for calculation of deflection, shear force, moments, and stresses in beams.

        Regards,
        Harshvardhan
        Ansys Help
        Ansys Learning Forum (Rules & Guidelines)

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