increasing displacement in EQ uniform analysis

[macropaine]

Dr. Silvia and Fmk
In my dynamic uniform EQ analysis, there is no negative displacement. The displacement rises to a large value, and then analysis ends to failure. I find displacement does not scale proportionally to gm factor, i.e. if I scale the gm but there is hardly any effect on the displacement.
My model is correct in static analysis, and the eigen is correct too.
Stangely, in my recorder of accel, it seems correct because positive and negative accel are recorded.
Thank you very much!

[fmk]

test your model assuming elastic properties .. then ask yourself why is the nonlinear model yielding so quickly that it goes 1 way and never comes back.

[macropaine]

Thank you for your reply, fmk.
But why it seems correct of the record of acceleration, because it oscillates with positive and negative value?

[macropaine]

I change the nonlinearelement to elasticelement, but the problem of record of displacement is the same as nonlinear element, displacement being positive.