4 Replies Latest reply on Sep 28, 2018 3:13 AM by Mats Lindqvist

    Unwanted Loads/Moments showing up with Load Case Manager results

    Thomas Webb
    Thomas Webb May 31, 2018 3:42 PM

      SW17 Premium (Academic Edition)

       

      I am using Load Case Manager to setup and run 11 primary load cases and 17 combination load cases. I am using a User-Defined coordinate system rather than the Global CS, and I have carefully selected my moments and forces in accordance with my User-defined CS. When I view the results table under the Results View tab, I am getting an additional load with the opposite sign populating an unmarked column adjacent to the non-suppressed load in the table. See images below of Load case table setup for Normal Force (NF) and the NF Results View. Attached setup file in .csv format below, and you will see that it also includes the (-100 N-m Moment about the x-axis), but there should not even be any value in that cell given the below definition.

       

      External Load - Remote Load Setup

       

      Load Case View

      - I only want a NF of -100 lbf along the z-axis, but LCM automatically added a -100 lbf-in moment about the x-axis for some reason. This has been occurring consistently (with different unwanted loads/moments showing up each time) and it is messing up my results as you will see in the Results View image below.

      Results View

       

      It seems like a bug in the software since since the Moment radio button isn't even checked in the Definition, but it keeps messing up my results each time I attempt to run the Load Case Manager. I have already tried closing/reopening the LCM and I have even deleted and rebuilt the LCM cases 3+ times to see if the software was holding onto some settings somewhere.


      Anyone have experience with this issue or will I need to address it directly with SW?

       

      Ladson

        • Re: Unwanted Loads/Moments showing up with Load Case Manager results
          Mats Lindqvist
          Mats Lindqvist Sep 27, 2018 10:09 AM (in response to Thomas Webb)

          I have a similar problem.I define two "remote loads" relative to a user defined coordinate system. The loads are applied to the same point, are equal in magnitude, act in 180degrees opposite direction, but are transferred to different surfaces. It is essentially a "pinching" function, that push surfaces apart in the structure, so the forces are equal in magnitude, acting along the same axis, at the same reference point, but with opposite direction. 

           

          My understanding is that the "remote load" functionality, should allow you to specify a load with a well-defined resultant with respect to a point, but transferred to a specified surface.

           

          The way I have defined this, this should not introduce any global resulting forces/moments acting on the structure, since the two load are in equilibrium, and cancel each other out. But my results suggests that I do get resulting reaction forces.  I get high stresses near fixtures, if I constrain the model using a flexible "elastic support", I get significant rigid body rotation. When I run the model without fixtures and "intertial relief", I get a warning message that there is significant external imbalance forces.

           

          I too run SW2017.