Modal analysis of a shell-payload structure using test data
This study evaluates the accuracy of computed modal frequencies obtained from a combined experimental/analytical model for a shell-payload structure. The total structure is physically divided into two subsystems, the shell and the internal payload, which are connected through a stiff joint. The payload was tested to obtain its free modes, while a finite element model of the shell was analyzed to obtain its modal description. A component mode synthesis technique was investigated which incorporates free modes and residual flexibility. The experimental modal data base for the payload was directly coupled with the finite element modal model of the shell to create an experimental/analytical model of the total structure. Both the translational and rotational elements of the payload mode shapes at the interface were measured and used in the coupling. The modal frequencies, computed using the combined experimental/analytical model, were then compared to those from a modal test of the entire structure. The sensitivity of the combined model to the residual flexibilities was also determined. Finally, recommended procedures for developing combined experimental/analytical models of shell-payload structures are given.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (USA)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 6402637
- Report Number(s):
- SAND-85-1301C; CONF-860224-4; ON: DE86002588
- Country of Publication:
- United States
- Language:
- English
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Combined experimental/analytical modeling using component mode synthesis
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