in a simple 2D model, stiffness and mass given, I am trying to get the same frequency when using a) mass b) mass changed into a force, and in analysis option the convert load to mass option for the modal analysis.
The mass direction is only in the z direction, for the a) option works fine, for the b) I get wrong results
Solved! Go to Solution.
1. Model type should be frame rather than truss (instability if support defined in one node only)
2. Support should be such that it restrains d.o.fs so that there is no instability
3. If you want to convert force into mass you have to define it first (case 3).
I'm attaching the corrected model.
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so it means that, first u have to define a load case with the force - new modal analysis and convert the force to mass of the load case with the force into the modal analysis.