1 Reply Latest reply on May 4, 2018 12:19 PM by Bill McEachern

    Difficulty With Spring Connector in Non-Linear Dynamic Study

    Dennis Pietrantoni

      Im running a study where I am accelerating a piston in a bore with a spring connector. The piston eventually hits a stop and I want to calculate the resulting impact forces. The issue I am having is with the spring connector. I notice when I have it in the model I get an error about stiffness on an element that is higher than the total elements I have in my solid mesh. I set up a simple non-linear dynamic model of two masses with a spring in between and it seams to solve fine. When the spring connector element is enveloped by another part (like a spring in a bore) the solver fails, even though the elements are not overlapping. I tried this in my simple two mass model and noticed when I raised the side walls of the larger mass to envelope the spring (but still not overlap it in volume), I get the same error. 

        • Re: Difficulty With Spring Connector in Non-Linear Dynamic Study
          Bill McEachern

          Why wouldn't you use the motion program to get the impact force estimate? Admittedly it will be a bit more approximate but an answer is better than no answer. There is nothing simple about NL dynamics in my experience with SWX Sim. No idea why you are having trouble. Does it work fine with out the spring all overlapping and what not? Large displacements with the spring connector might be an issue.  You could try replacing the spring with a solid element version of the same spring.