Unformatted text preview: s with a frequency sweep. Monitoring the displacement
of several key nodes (nodes 1, 41 and, 81) over the frequency range indicates the approximate desired natural
frequency as the point where the nodal displacements indicate a resonant condition.
In the second case, the lowest natural frequency is obtained using an unsymmetric matrix modal analysis (ANTYPE
= 2) corresponding to the frequency of mode one of the frequency data from the Lanczos unsymmetric eigensolver.
A preliminary finite element analysis (not shown here) was used to estimate a narrow range in which the 1st
even bending mode frequency occurs. In the first case, two unit loads at nodes 1 and 81 are arbitrarily used to
excite the desired bending mode of vibration. Results Comparison
Target ANSYS Ratio FLUID30 and SHELL63 f1, Hz 35.62 36.61 < f < 36.62 1.028 FLUID29 and BEAM3 f1, Hz 35.62 36.54 1.026 1. Solution from the reference under the same assumptions mentioned in the modeling notes. ANSYS Verification Manual . ANS...
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- Spring '09
- The Land, ........., Test Case