mniki2007
Computer
- Jul 3, 2007
- 12
hi dears:
I have a structure and do two seismic analyses with it.
1-spectrum analysis
2-transient analysis
But the thing that is very strange is different result obtained from them.
Stress, nodal displacement, and ......are different.
I expect that at least nodal displacement at top of structure to be the same,
But there are many differences between them, for example:
1-spectrum analysis: maximum x-component of displacement of top node of structure is: 35 cm
2-transient analysis: maximum x-component of displacement of top node of structure is: 3 cm
My seismic data in both analyses are the same and it is El Centro earthquake accelerogram.
But I integrate acceleration to obtain displacement versus time in transient analysis and do Fourier transform to obtain acceleration versus frequency for spectrum analysis.
In transient analysis I set displacement loads at base nodes in x direction and fix y and z directions.
Please someone help me why it happened?
Is it correct and common or I made mistake in some part of my analysis?
Thanks
Regards
I have a structure and do two seismic analyses with it.
1-spectrum analysis
2-transient analysis
But the thing that is very strange is different result obtained from them.
Stress, nodal displacement, and ......are different.
I expect that at least nodal displacement at top of structure to be the same,
But there are many differences between them, for example:
1-spectrum analysis: maximum x-component of displacement of top node of structure is: 35 cm
2-transient analysis: maximum x-component of displacement of top node of structure is: 3 cm
My seismic data in both analyses are the same and it is El Centro earthquake accelerogram.
But I integrate acceleration to obtain displacement versus time in transient analysis and do Fourier transform to obtain acceleration versus frequency for spectrum analysis.
In transient analysis I set displacement loads at base nodes in x direction and fix y and z directions.
Please someone help me why it happened?
Is it correct and common or I made mistake in some part of my analysis?
Thanks
Regards