Best practice for finding bend

UGMENTALCASEUGMENTALCASE
Hi all,
I have a clamp bar which I don't know what sort of forces the customer is using but after some time they are bending the material (basic mild steel s275jr). I wanted to run a check to see what other material would give me better results to help prevent bending over time.

Normally with this type of set up (see attached image) I would fix the middle section of the clamp (this is where it contacts the piece being clamped - yes it's a big gap, they wanted it with a big gap to put in different sized material pieces)

So fixed constraints in the centre where the piece being clamped it, then forces acting down on the screw holes, probably something to stop it skewing as well, like a frictionless support along the edge.
My question is what would your preferred way of doing this be? Is putting a force through the screw holes "correct" or is there a simpler/better way? With the forces being applied from a screw this is why I'm asking. Is it best practice to do it this way.

Thanks in advance

Comments

  • VictorVictor
    If you're using large displacements, the line of action for the force from each screw might change as it bends, otherwise, for linear analysis, I think using the hole would be fine since you're interested in the behavior away from the hole.

    The support in the middle might be an issue since it constrains it to almost two separate beams and prevents hogging in that region. If the piece being clamped isn't deforming (much), it might be better to constraint just two points at the edges.
  • UGMENTALCASEUGMENTALCASE
    Hi Victor thanks for the response. The piece being clamped is solid, so going no where. Imagine clamping a vice down to a machine bed, the vice isn't deforming.
    As for the bend and displacement I see what you mean by the line of action changing, I was basically going to put a preload value in Kn force on the holes to see what happens (value taken from a sort of cheat sheet of pre load values). I don't think they are seeing much bend but they really don't know so I was going to start there see what the bend is and then work on some ribs to reinforce and reduce the bend.
    It's bending approx 6mm, after adding some stiffening ribs I've reduced that to approx 3mm.
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