where can i found the option for element birth and death? (not the connection properties)
or is there any better solution for a spring system analysis, spring will be built as CBUSH element (nonlinear), with the different curves for loading and unloading,
at present, i am thinking using
1. element birth / death option (built 2 Cbush elements)
2. using restart previous analysis
welcome for more options!
Element birth and death is only available in the Advanced Nonlinear solver and you must manually add an EBDSET=setID card to the Case Control section and a second EBDSET card to the Bulk Data section that contains the EBDSET id, time of birth, time of death and the list of elements in this set.
These are documented in the NX Nastran Quick Reference Guide.
Thanks for your answer,
I tried to add
EBDSET=1 by clicking ''Start Text (On/Off)'' in Nastran Executive and Solution Options Tab,
then in Nastran Bulk Data Options Tab, i again clicked ''Start Text (On/Off)''
EBDSET 1 0 1 1
for the model
2 Nodes, NID 1 & 2,
2 CBUSH, EID 1 & 2 (both elements use nodes 1 and 2),
loading time 0s ==> 5s
element 1 death time = 1
analysis time 0s ==> 3s
there is no error, but alos no result come out.
1 user information massage 480 (XSEMIN)
Job terminated due to lack of SOL, Compile, or Link cards....
Can you take a look at my model when you have time, i really appreciate your help
For the Case Control card, you should remove the entry in the Executive Solution section and add it to the end of the Master Requests and Conditions section.
The format for the Bulk Data EBDSET card is EBDSET SetNumber BirthTime DeathTime ElementIDs, so in your case, the Bulk Data Entry should be:
EBDSET 1 0. 1. 1
I've attached a Femap Neutral file with some beams and two CBUSH elements as supports. CBUSH element 1 uses the EBDSET cards in Analysis Set 2 and from the Chart and the criteria plots at the final time, you can see element 1 is removed at Time = 1.0.