Non-linear time history analysis warning/error

Creation date: 11/13/2018 4:55 PM    Updated: 11/14/2018 3:26 AM    nonlinear analysis non-zero values zero section properties zero stiffness
Question:

I seem to have come across the error shown by the command window below when trying to undertake a non-linear analysis of a bridge model.

Could you advise on the necessary actions or modelling causes of this error. My Model is attached.





-----------------------------------------S T A R T I N G       S O L U T I O N

MULTI-FRONTAL SOLVER
AVAILABLE MEMORY =    5.6 GBYTES
GPU ACCELERATION : DISABLED (NO CUDA SUPPORTING GPU)
ENTRY NUMBERING_EQN 
ENTRY FORM_STIFF_MASS_LOAD 
THE INDIVIDUAL ELEMENT STIFFNESS AND LOAD MATRICES WILL NOW BE FORMED.
  ELEMENT NO. :  12136  OF   12136
ENTRY SOLUTION PHASE 

WARNING : For the non-linear time history analysis with the direct integration method,      
          Area, Ixx, Iyy and Izz of the beam section property must have non-zero values     
          so that corresonding flexibility matrices do not become singular.                 

          This type of the problem may happen in the nonlinear time history analysis of     
          the 2D-model with zero section properties related to the out-of-plane deformation.

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ERRORS ENCOUNTERED.  MIDAS JOB TERMINATED. REFER TO .OUT FILE
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Answer:

Hello ,

The reason for this error are the dummy members which have section proprety "Wireframe". This section has so small dimensions that the section properties are extremely small and due to normal computational rounding is considered as zeros. This is not acceptable for the analysis and the software give an error message and terminates the analysis.

If you delete the wireframe members you should be able to run the analysis.

Kind regards,
Technical Support Team
MIDAS UK
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