I been tinkering with transient analysis, I am currently having some trouble with modal superposition method. I am having trouble understanding how to correctly implement the Control_implicit_modal_dynamics keyword. In the direct transient analysis method I can just utilize the implicit solver to directly find the response of my model using the load_node or load_node_set keywords.
The current errors I get are:
1. Error 21122 (STR+1122) The file C:\LSDYNA\Dyna_examp does not exist
2.Error 60319 (IMP+319) Binary modal database C:\LSDYNA\Dyna_examp is not compatible with this execution. Use a double precision version of LS-DYNA when creating the database along with IBINARY=0 on *DATABASE_FORMAT. Then use a double precision version of LS-DYNA for the modal simulation. Double precision is recommended for ALL modal jobs.
I am already using the double precision solver in LS-Dyna.
Control keywords I am currently using are:
1. Control_implicit_general
2. Control_implicit_eigenvalue
3. Control_implicit_modal_dynamics
4. Control_termination
I am also currently using load_node_set which might not be correct for this case.
Any help on implementing Control_implicit_modal_dynamics would be of great help.
Unfortunately, I am not nearly as familiar with the implicit side of LS-Dyna as I am with the explicit.
Those errors are strange and seem like something that may be going on with your license. I'll look into both of these and get back to you.
I was able to get transient analysis working using implicit_dynamics setting analysis type to modal superposition, however the results were very noisy. I have compared the LS-Dyna results with other solvers such as the Optistruct modal superposition solver and the direct integration method in LS-Dyna and Optistruct. The modal superposition method in LS-Dyna is highly effected by the modes of the model, which makes the results noisy.