Dynamic analysis is not convergent

[enginer]

When I perform dynamic analysis, the ground motion is small，but it is not zero.The model does not converge. If the ground motion before the model does not converge is set to zero, it can converge, and the error is reported as follows：
current EnergyIncr: -nan(ind) (max: 1e-06) Norm deltaX: nan, Norm deltaR: nan
AcceleratedNewton::solveCurrentStep() -The ConvergenceTest object failed in test()
DirectIntegrationAnalysis::analyze() - the Algorithm failed at time 7.70976
OpenSees > analyze failed, returned: -3 error flag
What causes this and how can it be solved？

[fatpanda]

I understand you're facing convergence issues with small ground motions in OpenSees. This can be tricky, but here are a few quick tips to try:

• Check Your Time Step: A smaller time step can sometimes solve convergence problems in dynamic analysis.
  
  Review Model Parameters: Make sure your material properties and boundary conditions are set correctly.
  
  Adjust Convergence Criteria: Loosen your convergence criteria a bit, especially if they're very strict.
  
  Incremental Loading: Apply ground motion gradually, starting from very small and increasing slowly.
  
  Simplify and Debug: Start with a simpler version of your model and then add complexity. This can help identify where the issue lies.

spbo Convergence issues can be a bit of a puzzle, but these steps often help sort them out. Keep experimenting, and don't hesitate to ask for advice on the OpenSees forums. Good luck!