Neagitive inertia on node error

gopal_rathore
gopal_rathore Altair Community Member
edited October 2020 in Community Q&A

Hi,

I am getting an error of negative inertia on node. I have switched on the implicit option by entering the key words in the radios engine file. When I perform the same in the explicit mode, no error comes and the simulation runs smoothly. On checking the nodes by ID I can see that these nodes are on the master contacts  surfaces of TYPE 2 contact. Attached file has snapshot of error message.

Kindly let me know about the same.

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Answers

  • Rahul Rajan_21763
    Rahul Rajan_21763 New Altair Community Member
    edited June 2015

    Hi,

    In case of the interface TYPE2 the use of SPOTFLAG=0, can cause an error of RADIOSS ENGINE at 1st cycle due to a negative mass or inertia of a master node of the segment. This can also cause an error of RADIOSS ENGINE during the run, due to a negative stiffness on a master node of the segment:

    ** ERROR : NEGATIVE STIFFNESS NODE …

    In case of the interface TYPE2 uses SPOTFLAG=1, the situation corresponding to this message can cause a relatively important added mass at 1st cycle on the master nodes of the segment.

    Try to replace this tied interface with TYPE 7 and try running the job.

    Regards

    Rahul R

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