We notice a difference in dynamic responses (frequency, stress) when modeling insulation using unit weight versus thickness+density. We see the same dynamic response difference in versions we have (2017, 2019)

Static center of gravity report and static output results show the same numbers for both input methods.

Using a simple cantilever model (anchored on one end, 1m long, OD=21.336mm, t=2.7686mm, material 157), the frequency from the thickness+density input matches theoretical values. Frequency using insulation unit weight input do not.


Insulation unit weight = 0.29 N/cm, Total weight (pipe+ins) = 41.7N, 1st mode f = 17.8Hz (close to f for an uninsulated pipe)

Insulation thickness, density = 51.61mm, 0.00025 kg/cm3, Total weight (pipe+ins) = 41.7N, 1st mode f = 9.8Hz


Should another insulation field be populated together with unit weight? Appreciate any help we can get. Thanks in advance.