FEM acoustics of a simple box model with SSD

This is a simple box model to show how to couple FEM acoustics with steady state dynamics (SSD). Example 9.3 from LS-Dyna training class NVH, Fatigue and Frequency Domain Analysis with LS-DYNA by Yun Huang.

*BOUNDARY_SPC_SET
*CONTROL_IMPLICIT_EIGENVALUE
*CONTROL_IMPLICIT_GENERAL
*CONTROL_IMPLICIT_NONLINEAR
*CONTROL_TERMINATION
*CONTROL_TIMESTEP
*DATABASE_BINARY_D3PLOT
*DATABASE_FREQUENCY_BINARY_D3ACS
*DATABASE_FREQUENCY_BINARY_D3SSD
*DEFINE_CURVE
*ELEMENT_SHELL
*END
*FREQUENCY_DOMAIN_ACOUSTIC_FEM
*FREQUENCY_DOMAIN_SSD
*KEYWORD  
*MAT_ACOUSTIC
*MAT_ELASTIC
*NODE
*PART
*SECTION_SHELL
*SECTION_SOLID
*SET_NODE_LIST
*TITLE

*KEYWORD  
*TITLE
LS-DYNA keyword deck by LS-Prepost                                              
*FREQUENCY_DOMAIN_SSD
         1       100     0.000     0.000         0         0         0
  0.010000         0         0     0.000     0.000
     0.000     0.000         0         0         0         2         3         0
       666         0         3         0        10       200         0         0
*DATABASE_FREQUENCY_BINARY_D3SSD
         1
       10.      100.        10
*FREQUENCY_DOMAIN_ACOUSTIC_FEM
      1.23      340.       10.      100.        10                         2.e-5
         1
         2         3
        20         1
*DATABASE_FREQUENCY_BINARY_D3ACS
         1
*CONTROL_IMPLICIT_EIGENVALUE
       100     0.000         0     0.000         0     0.000         0     0.000
         0         0         0         0
*CONTROL_IMPLICIT_GENERAL
         1  1.000000         0         0         0         0         0         0
*CONTROL_IMPLICIT_NONLINEAR
         1         0         0     0.000     0.000     0.000     0.000     0.000
         0         0         0         0
         0         0     0.000         1         2
*CONTROL_TERMINATION
  0.020000         0     0.000     0.000     0.000
*CONTROL_TIMESTEP
     0.000  0.900000         0     0.000 -1.100E-6         0         0         0
     0.000         0         0
*DATABASE_BINARY_D3PLOT
  0.001000         0         0         0         0
         0
*BOUNDARY_SPC_SET
         1         0         1         1         1         0         0         0
*SET_NODE_LIST
         1     0.000     0.000     0.000     0.000          
        33        44        55        66        77        88        99       110
       121        22        11        67        56        45        34        23
        12         1        78        89       100       111         0         0
*PART
boxsolid                                                                        
         1         1         1         0         0         0         0         0
*SECTION_SOLID
         1         8         0
*MAT_ACOUSTIC
         1     1.220     340.0

*PART
boxsurface                                                                      
         3         3         3         0         0         0         0         0
*SECTION_SHELL
         3        16  1.000000         3         0         0         0         0
  0.010000  0.010000  0.010000  0.010000     0.000     0.000     0.000         0
*MAT_ELASTIC
         3 7800.00002.1000E+11  0.300000     0.000     0.000         0
*DEFINE_CURVE
*SET_NODE_LIST
*ELEMENT_SHELL
*NODE
*END