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
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
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/