3 Replies Latest reply on May 3, 2012 9:22 PM by Jerry Steiger

    Ship longitudinal strength in Simulation

    Bob Kearney

      Has any tried to use Simulation to analyze global longitudinal strength of a ship's hull while afloat? I have attempted to do this, but I am not pleased with the results. To start with I am simply considering a "prismatic" barge. My methodology was:

       

      Solidworks:

       

      1) Import ship midship section from an already created AutoCAD file

      2) extrude midship section over desired length

      3) apply steel material

       

      Simulation:

      4) Start static analysis

      5) Treat model as beam

      6) Apply buoyancy pressure to under water part of hull as non-uniform distribution

      7) Add cargo weight as equally applied load to deck

      8) Mesh and run

        • Re: Ship longitudinal strength in Simulation
          Bill McEachern

          I would use symmetry - as much as you can - 1/2 at least maybe a 1/4. I would use a surface model. (extrude the mid planes, though it would hardly be sensitive to small conveniences taken) I don't think the non uniform pressure distriution will work on a hull girder modeled as a beam element as it has no dimension in the direction just a real constant set. Make sure that Signma F = 0. If you are sure, turn on inertial relief and/or soft springs in the study properties. Hope that helps. For frequency you would need to abondon symmetry and add the added mass.

          • Re: Ship longitudinal strength in Simulation
            Bob Kearney

            So, I have had some success. It seems that Bill McEachern's point of applying pressure was correct. Instead I applied buoyancy as a force. It seems to work. My only issue is whether or not to apply gravity as an external load. The documentation is not very clear on when it should be applied. Any comments?