Different Frequency outputs between only frequency step and a frequency step in multstep analysis

[aurum]

Hello,

Model: Dam-foundation-reservoir system - Linear analysis

Why do I get different frequencies when I run my model only for a frequency step and a frequency step in a multistep analysis?

For example,

1. Frequency step - mode 1 frequency is 1.73 Hz
2. Frequency step - Gravity step - Time History Step - Frequency step - mode 1 frequency is 2.01 Hz in both frequencies steps here

Ignore multi-frequency steps in example #2, as the sequence was initially prepared for a non-linear analysis

 

[FEA way]

What if you suppress all the steps after the first frequency one in the second caase ? Also, are all the settings identical ? Export input files fro, both cases and compare them using text editor.

 

[aurum]

Yes! Thank you. It worked when I suppressed all the subsequent steps. Looks like there is some difference between the two models.