CCX Post processing problem

swarajswaraj
Hey,As i was using mecway trial version to evaluate it, I only got 1000 nodes.So I decided to use calculix solver instead.I tried basic ball impacting a plate to test its post processing and value. But the problem I am getting is that the ball keeps on oscillating back and forth instead of impacting the plate.Please help me, because i know its some minor glitch that i cant see. Here are the inps file. image

Comments

  • VictorVictor
    Hello. Could you attach the 6 *INCLUDE files too?

    You might also try the CCX forum: https://groups.yahoo.com/neo/groups/CALCULIX/info
  • SergioSergio
    As far as I rememeber we have talked about this sample problem in this forum, look for my post because I have posted the working model.
  • swarajswaraj
    @Victor ,These are the files.
    JUst to check i took a working inp file from net and tried to process it on my ccx (Ball impacting a plate). It didn't work.Its impacting but stresses are not visible.and the ball (solid sphere) gets contracted
  • swarajswaraj
    The upper crumble part is the sphere.
  • AndreaAndrea
    Why *Rigid Body? Try locking the cube with simple node constraints.
  • SergioSergio
    edited January 2018
    In case of using RIGID BODY you should add a second reference node to be able to block also the rotations DOFs.

    Check this thread

    mecway.com/forum/discussion/comment/1247/#Comment_1247
  • swarajswaraj
    Thats the thing,I didnt specify the body as rigid in ccz wiard.I applied node constraints. It is automatically considering it as *RIGID BODY. DOes it explain the oscillation of ball without impacting the plate?
  • AndreaAndrea
    edited January 2018
    CGX shows deformations on both ways so the real behaviour is not an oscillation. Check the displacement magnitude vs time step on g direction to be sure. Simplify constraints to understand where is the problem.
    I ran the solver and is strange that after some time step also the cube is on rigid body motion
  • SergioSergio
    edited January 2018
    Just make a try blocking DOF 1,2 and 3 on the nodes at the base of the cube (and removing rigid body card). As I understand, now with the rígid body you will have a rotation when the ball impact the cube as there are no rotational restrain (or even for the own cube weight due to the gravity). Otherwise add a second reference node to restrain the rotations on the rígid body.
  • swarajswaraj
    edited January 2018
    First,I want to thank you for all the quick response,This forum is active and helpful as hell.Now coming to the situation, How can I remove rigid body card directly from include file ?. Because I didn't select the rigid body card and its considering it as one. The moment I constraint the motion of the cube in the DOF section , it inputs as rigid in the add contact file.

    I checked the displacement of the ball with time step and I saw weird kinematics value and stress value.I am attaching he gif file of that animation. The ball impacts the cube the first and it shows minor strain changes, the third impact is the major one where you can see the observable strain changes but it bounces back after the fifth contact.What these sequential impact signifies? Is it due to the collision restitution or is it due to some convergence problem ?
  • SergioSergio
    For removing the rígid body card, just delete the line that says RIGID BODY. Check the thread that I mention before as I had some similar problems.
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