Error regarding computation of nodal forces

[Vaibhav Dnyaneshwar Kulkarni]

Greetings to All,

I am currently conducting a steady-state frequency response analysis of a human body finite element model using LS-Dyna. I have applied an acceleration load and obtained the frequency domain response using the mode superposition method with the FREQUENCY_DOMAIN_SSD keyword. For modal analysis, I have used the CONTROL_IMPLPLICIT_EIGEN_VALUE and CONTROL_IMPLICIT_GENERAL keywords.I also turned on modal stress computation flag (MSTRES=1)

I encountered an issue where the nodal forces, which are one of the output parameters of the frequency response analysis, are not being correctly recorded. I used the DATABASE_NODAL_FORCE_GROUP option for force requests, but the corresponding ASCII nodal force file (nod_for) is showing zero nodal forces on the requested nodes. I have tried both SMP and MPP methods, but the forces remain at zero.

If anyone has insights or suggestions related to this issue, I would greatly appreciate your input.

Thank you,
Vaibhav.