Rigid Body Analysis: Accelerations are exceeding internal limit.

- March 4, 2020 at 10:01 am
  
  pedroksm
  Subscriber
  
  I am trying to simulate knee kinematics in Ansys Rigid Body Dynamics. After setting all conditions, I cannot run the simulation, because of this error: Accelerations are exceeding internal limit. Solution will not proceed.
  
  Does anyone have any idea about this type of error?
- March 4, 2020 at 2:54 pm
  
  peteroznewman
  Subscriber
  
  The mass is too low, the force is too high or the time is too long.
- March 5, 2020 at 3:25 pm
  
  pedroksm
  Subscriber
  
  Thank you for your fast answer. I am trying to change the model with your tips.
  
  I have no force in the system, just motion (rotation). Moreover, I changed density and added a remote mass.
  
  For both cases, it says: "Although the solution failed to solve completely at all time points, partial results at some points have been able to be solved. Refer to Troubleshooting in the Help System for more details."
- March 5, 2020 at 6:41 pm
  
  peteroznewman
  Subscriber
  
  This is a big improvement because you have results for some period of time. You have to look at the error that stopped the solver to reaching the End Time.
- March 11, 2020 at 1:54 pm
  
  pedroksm
  Subscriber
  
  Yes, it was an improvement. Now, I am trying to solve this problem. It was a time step problem.
  
  Moreover, I am trying to change density of a body over time, do you know if APDL commands are usable in Rigid Body Dynamics module?
  
  I was also trying to use non-linear springs with variable stifness and it does not work if added by APDL commands.
- March 12, 2020 at 12:55 am
  
  peteroznewman
  Subscriber
  
  I don't think APDL commands work in Rigid Dynamics because that uses a different solver to the core Mechancial APDL solver that is the basis for the Structural models.
  
  You might try running the model in Transient Structural where you can use APDL commands, but the solution time will probably increase greatly.