3 Replies Latest reply on Oct 21, 2010 4:06 PM by Anthony Botting

    Dynamic Stress Analysis

    Robin McCaffrey

      Hey, I'm trying to get solidworks to do a dynamic stress analysis.

       

      See the attached assembly.  In it contains a piston, connecting pin, connecting rod, and a very simple crankshaft.

       

      I have specified a curve pressure loading on the assembly, a hinge fixture on the crank and a no penetration contact set between the pin and connecting rod and the crank and connecting rod.

       

      I'm wondering how to specify initial condition of 6000rpm, and how to run the simulation from tdc to bdc or for that first 0.005s

        • Re: Dynamic Stress Analysis
          Anthony Botting

          That is a very interesting question. The Simulation is not really designed to do rigid body motion - although you could, but I have never seen that done in the context of FEA. I suspect it will take a very long time to run due to updating of the stiffness matrices with each time increment. The quickest approach I might take is to run the model in SolidWorks Motion and get the reaction forces as a function of time and piston position. You can then extract those values (and positions of everything) at the specific time step of interest (or many time steps)  and send them to the "Simulation" FEA module, and run a simple static analysis (inertia forces will be included). Hope that helps. -Tony

            • Re: Dynamic Stress Analysis
              Robin McCaffrey

              I found in solidworks motion, that they have a stress analysis option.  I'm going to play around a bit more.  I believe it is taking the constraints from my simulation analysis and applying them.  I ran it once and it analyzed the stresses in the simple crank shaft.  I'll play around a bit more and hopefully get them in the connecting rod next round and yes, you're right, it does take a long time for it to run through.

               

              Other cool notes is that looking at the animated stress, you can clearly see when the cylinder pressures and overpower the inertial forces and vice versa