negative time?

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macropaine
Posts: 29
Joined: Fri Dec 21, 2007 5:39 am
Location: China

negative time?

Post by macropaine »

Dr. Silvia,

There is negative time in my nonlinear anaytical result in recorder.
Could you tell me what likely causes this stange problem and how to solve it?
Thanks.
silvia
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Joined: Tue Jan 11, 2005 7:44 am
Location: Degenkolb Engineers
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Post by silvia »

it is actually the pseudo time, proportional to the lateral load.
this should be in a static analysis, though, not in a dynamic analysis.
Silvia Mazzoni, PhD
Structural Consultant
Degenkolb Engineers
235 Montgomery Street, Suite 500
San Francisco, CA. 94104
macropaine
Posts: 29
Joined: Fri Dec 21, 2007 5:39 am
Location: China

Post by macropaine »

yes. It is static analysis. But why the lateral load becomes negative? Is my model or constitutive law error?
silvia
Posts: 3909
Joined: Tue Jan 11, 2005 7:44 am
Location: Degenkolb Engineers
Contact:

Post by silvia »

there is no concept of time in a static analysis.
you use that time to interpolate where you are in the lateral-load application.
Silvia Mazzoni, PhD
Structural Consultant
Degenkolb Engineers
235 Montgomery Street, Suite 500
San Francisco, CA. 94104
macropaine
Posts: 29
Joined: Fri Dec 21, 2007 5:39 am
Location: China

Post by macropaine »

I have to get the lateral load from the time. I don't know how to determine the lateral load for the negtive time. So I think something is wrong. Should I check my model and constitutive law carefully?
silvia
Posts: 3909
Joined: Tue Jan 11, 2005 7:44 am
Location: Degenkolb Engineers
Contact:

Post by silvia »

nothing is wrong. the lateral load is proportional to time, you have to go back and see how you defined your lateral load vs. time/analysis increment.
i'd just use a recorder.
Silvia Mazzoni, PhD
Structural Consultant
Degenkolb Engineers
235 Montgomery Street, Suite 500
San Francisco, CA. 94104
macropaine
Posts: 29
Joined: Fri Dec 21, 2007 5:39 am
Location: China

Post by macropaine »

[quote]i'd just use a recorder.[/quote]
What do you mean?
Thank you.
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