Dear friends and bentley Colleagues
I'm confused on the DAF calculation...
We can use the DAF to get the dynamic response from the static analysis result, am i right?
And I noticed that SNAME has a complicated procedure for DAF analysis. Surely we can get the DAF for Base shear, Overturning, and motions.
However, in SACS
1, we can perform dynamic response analysis by "mode extraction" method, and generate the equivalent static force for structural nodes which includes the inertia force. So we needn't solve the DAF value separately.
2, By performing the dynamic response analysis, e.g., the deterministic wave response analysis, we can extract the DAF values. it's simple compared to SNAME's MPME method.
Then, Why class code still suggest following sname's approach, for example, ABS GUIDANCE NOTES ON DYNAMIC ANALYSIS PROCEDURE FOR SELF-ELEVATING UNITS?
Thanks!
Sea wave is random by nature. Deterministic DAF cannot represent realistic dynamic effect especially for dynamic sensitive structure like Jack up.
Stastistic method likes the one recommended in SName is more suitable