Should I be concerned about the warning message below when
I run a squeeze film damping analysis with FLUID136?
*** WARNING *** CP= 132.562 TIME= 11:48:18
Beta damping multiplier: -2.356628492E-07
A negative beta damping multiplier occurs. Please check results
carefully!
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Squeeze film damping tends to be of the viscous type, which produces a high alpha damping value and low beta damping value. The alpha and beta damping values are computed based on the damping at two frequencies as described in the Structural Analysis Guide, Section 5.9.3. The Beta value solved for in this way can be negative. This means that the damping is decreasing rapidly with frequency, even more than 1/omega. You can specify this negative betad value in a transient analysis. |
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