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High response misplaced

High response misplaced

High response misplaced

(OP)
Running a frequency response in a structure and plotting the accelerations at specific locations, from 10-100 Hz

The resonance modes in these locations are in the range 60-80Hz, but the maximum plotting the maximum accelerations, these maximum appear at 25-35Hz, which is not expected. Anyone experienced this before? What is the reason for that? It seems something is wrong.

I defined the frequencies in nastran, and included all the resonance modes, 5 points per node.
The load acceleration is defined for the range of 10-100Hz, with unit input 1m/s^2



RE: High response misplaced

Hello!,
Depending the version of Simcenter NASTRAN you run probably is a drift effect. You need to activate the option "Relative Enforced Motion Results" in the NASTRAN Output Request.
This was a bug in Simcenter NASTRAN reported by me, update your software and make sure to run the latest version.



Best regards,
Blas.

~~~~~~~~~~~~~~~~~~~~~~
Blas Molero Hidalgo
Ingeniero Industrial
Director

IBERISA
48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog de FEMAP & NX Nastran: http://iberisa.wordpress.com/

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