A mass-spring model

This is an example of a mass-spring model under base acceleration power spectral density excitation. *DATABASE_FREQUENCY_BINARY_D3PSD and *DATABASE_FREQUENCY_BINARY_D3RMS are used for post-processing of the results. Example 6.7 from LS-Dyna training class NVH, Fatigue and Frequency Domain Analysis with LS-DYNA by Yun Huang.


*CONTROL_IMPLICIT_EIGENVALUE
*CONTROL_IMPLICIT_GENERAL
*CONTROL_IMPLICIT_NONLINEAR
*CONTROL_TERMINATION
*DATABASE_BINARY_D3PLOT
*DATABASE_DEFORC
*DATABASE_FREQUENCY_BINARY_D3PSD
*DATABASE_FREQUENCY_BINARY_D3RMS
*DATABASE_HISTORY_NODE_SET
*DATABASE_NODOUT
*DEFINE_CURVE
*ELEMENT_DISCRETE
*ELEMENT_MASS
*ELEMENT_SHELL
*END
*FREQUENCY_DOMAIN_RANDOM_VIBRATION
*KEYWORD  
*MAT_DAMPER_VISCOUS
*MAT_ELASTIC
*MAT_SPRING_ELASTIC
*NODE
*PART
*SECTION_DISCRETE
*SECTION_SHELL
*SET_NODE_LIST
*SET_SEGMENT
*TITLE

*KEYWORD  
*TITLE
Spring subjected to base acceleration
*FREQUENCY_DOMAIN_RANDOM_VIBRATION
         1        20
      0.01
         1         1         3    9810.0

                   0         3      1000
*DATABASE_FREQUENCY_BINARY_D3PSD
         1
       10.      100.       901 
*DATABASE_FREQUENCY_BINARY_D3RMS
         1
*CONTROL_IMPLICIT_EIGENVALUE
         2         0
         0         0         0         0         1
*CONTROL_IMPLICIT_GENERAL
         1  1.000000
*CONTROL_IMPLICIT_NONLINEAR
         1
         0         0         0         0
         0         0     0.000         1         2
*CONTROL_TERMINATION
  1.000000
*DATABASE_HISTORY_NODE_SET
         1
*DATABASE_DEFORC
  0.001000         1
*DATABASE_NODOUT
  0.001000         1
*DATABASE_BINARY_D3PLOT
  0.100000
         0
*PART
spring
         1         1         2
*SECTION_DISCRETE
         1
     0.000     0.000
*MAT_SPRING_ELASTIC
         2    6.4454
*PART
damper                                                                          
         2         1         1
*MAT_DAMPER_VISCOUS
         1 0.0005129
*PART
plate                                                                           
         3         3         3
*SECTION_SHELL
         3         2  1.000000         2         1         0         0         1
  5.000000  5.000000  5.000000  5.000000
*MAT_ELASTIC
         3  0.281793 2.908E+20  0.300000
*DEFINE_CURVE
      1000
          10.0000000           0.1 
         100.0000000           0.1
*SET_NODE_LIST
         1
         1         2
*SET_SEGMENT
         1
         1         3         4         5
         3         1        11        10
         1        12        13         5
         1        12        16        11
*ELEMENT_SHELL
*ELEMENT_DISCRETE
*ELEMENT_MASS
*NODE
*END