2 Replies Latest reply on Apr 16, 2017 3:41 AM by Stan Hon

    Mixed mesh beam and solid results 'still' confusing

    Stan Hon

      Hi there, this is the first time I do mixed mesh using beam and solid elements. As can be seen from the pictures of a trailer chassis, I have applied load on the longitudinal under-run bar at the bottom. I have checked that the displacement is good with the beam and solid bonded together well (I am using the same element size for both). The problem is that when I increase the thickness of the triangular gusset, the maximum bending stress is still the same at the same location. In short, the effect of the gusset does not seemed to be captured by the FEA. Why so?

        • Re: Mixed mesh beam and solid results confusing
          Keith Frankie

          Are the bodies that are being meshed with solid elements correctly bonding to the beams?  Check the displacement plot (with a large deformation scale) to see if they're moving together as anticipated.  Look at the stresses within the solids to see if they're actually carrying any loads.

           

          Note that beam elements only give relevant results along the beam itself.  Results at joints, or where other geometry exists (as you have) won't be realistic.  To get real results in this area you would need to use a solid mesh throughout the joint.  You could transition to a beam mesh outside the joint area.

            • Re: Mixed mesh beam and solid results confusing
              Stan Hon

              Thanks Keith for your straight to the point answer. I have checked the displacement plot and the animation played out exactly as if the solids are bonded to the beams (i.e. moving together) but somehow the stresses appeared to be very small for some solids. (Please refer below picture). Your advice on using solid mesh throughout the joint is very true. I guessed I need to breakdown the beams so that at the attachments to solids, only solid mesh will be used throughout and onwards I will use beam elements mesh. I think my problem is something to do with the bonding of solid to a weird profile beam (I created my own weldment profile for the longitudinal "C" frame). It could've been better if it bonded to square/ rectangular beams (just my opinion).

               

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