2 Replies Latest reply on Jun 3, 2014 8:49 PM by Jared Conway

    Simply Supported Beam Deflection

    Robert D.

      Hello I am trying to run an analysis on a simply supported beam. The hand calculations do not match the deflection I see when the analysis is complete. Any help is greatly appreciated.

        • Re: Simply Supported Beam Deflection
          Shaun Densberger

          I'm not too familiar with SW beam elements, but there were two issues I noticed when playing with this in 2014:

           

          1. Your constraints were defined on the end faces of the part (not the joints).
          2. You're using a fixed constraint, so your finite element model is that of a fixed-fixed beam.

           

          Item #1 prevented me from running the model, and Item #2 will prevent you from getting the expected results. After fixing Items #1 and #2, I get a peak displacement of 36.42 in.

           

          I should point out that this displacement value is large enough to violate small displacement theory, so please keep this in mind when using the results.

           

          EDIT: I totally fubbed up my constraints and didn't realize it until I read Jared's post. I did a pin-pin, not a pin-roller. I can't get a license at the moment, but a pin-roller should give you a value larger than what I gave.

          • Re: Simply Supported Beam Deflection
            Jared Conway

            this question gets answered a lot. almost always it is a matter of what your calculatin is, the assumptions it makes and whether your setup matches simulation. unlikely that the software is not solving a standard problem correctly. look at the AFNOR document and validation examples for more information on standard examples

             

            what are the assumptions in your hand calculation? like shaun says, if you violate the small displacement theory, static analysis be invalid

             

            beam, shell, solid, all have different assumptions regarding idealization. do any of them match?

             

            your restraints have to match. simply supported would mean that one end should be able to slide. does that happen?