Non linear time history analysis
Non linear time history analysis
(OP)
hello everyone,
I am trying to do time history analysis (both linear and non linear) on a simple frame. The result obtained are seems quite absurd to me, which I am enlisting in here. Kindly throw some light on the possible mistake I might be committing.
Base shear from linear modal analysis= 1554 kN
Base shear from non-linear modal analysis= 1554 kN
Base shear from linear direct integration analysis= 1183 kN
Base shear from non-linear direct integration analysis= 1532 kN
I am also not clear about how to provide non-linearity in the structure, as I am not considering geometric non-linearity. Only non linearity to be considered is material non-linearity.
your guidance will be highly appreciated.
I am trying to do time history analysis (both linear and non linear) on a simple frame. The result obtained are seems quite absurd to me, which I am enlisting in here. Kindly throw some light on the possible mistake I might be committing.
Base shear from linear modal analysis= 1554 kN
Base shear from non-linear modal analysis= 1554 kN
Base shear from linear direct integration analysis= 1183 kN
Base shear from non-linear direct integration analysis= 1532 kN
I am also not clear about how to provide non-linearity in the structure, as I am not considering geometric non-linearity. Only non linearity to be considered is material non-linearity.
your guidance will be highly appreciated.





RE: Non linear time history analysis
Generally, many are used and a average is done for design.
Note 2 : If you want to compare, you need to model with the same damping for all analysis.
Note 3 : If you want to do Non-Linear Analysis in earthquake engineering, the most important aspect is off cource the material non-linearity and not the geometric non-linearity !
Geometric non-linearity, as negative stiffness, will soften you structure (increase you periods and then decrease force response) Be cautious of that !