SSD with base and enforced motion — Welcome to LS-DYNA Examples

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This sequence of two examples shows how to set up an input file for large mass method. In the first file a rectangular plate is computed with base acceleration using *FREQUENCY_DOMAIN_SSD. In the second file for the same structure large mass method is applied with keywords *CONTROL_FREQUENCY_DOMAIN, *ELEMENT_MASS_NODE_SET and *BOUNDARY_SPC. Example 5.2 from LS-Dyna training class NVH, Fatigue and Frequency Domain Analysis with LS-DYNA by Yun Huang.

Keywords

*BOUNDARY_SPC_SET
*CONTROL_IMPLICIT_EIGENVALUE
*CONTROL_IMPLICIT_GENERAL
*CONTROL_IMPLICIT_SOLUTION
*DATABASE_FREQUENCY_ASCII_NODOUT_SSD
*DATABASE_FREQUENCY_BINARY_D3SSD
*DATABASE_HISTORY_NODE_SET
*DATABASE_NODAL_FORCE_GROUP
*DEFINE_CURVE
*ELEMENT_SHELL
*END
*FREQUENCY_DOMAIN_SSD
*KEYWORD  
*MAT_ELASTIC
*NODE
*PART
*SECTION_SHELL
*SET_NODE_LIST
*SET_SEGMENT
*TITLE


*BOUNDARY_SPC_SET
*CONTROL_FREQUENCY_DOMAIN
*CONTROL_IMPLICIT_EIGENVALUE
*CONTROL_IMPLICIT_GENERAL
*CONTROL_IMPLICIT_SOLUTION
*DATABASE_FREQUENCY_BINARY_D3SSD
*DATABASE_HISTORY_NODE_SET
*DATABASE_NODAL_FORCE_GROUP
*DEFINE_CURVE
*ELEMENT_MASS_NODE_SET
*ELEMENT_SHELL
*END
*FREQUENCY_DOMAIN_SSD
*KEYWORD  
*MAT_ELASTIC
*NODE
*PART
*SECTION_SHELL
*SET_NODE_LIST
*SET_SEGMENT
*TITLE

Reduced Input

*KEYWORD  
*TITLE
A rectangular plate subjected to base acceleration excitation
*FREQUENCY_DOMAIN_SSD
         1        20     0.000     0.000         0         0
  0.020000         0         0     0.000     0.000
                                                           1         2         0
         0         0         3         3       100       200         0         0
*DATABASE_FREQUENCY_ASCII_NODOUT_SSD
  1.000000 500.00000       500
*DATABASE_FREQUENCY_BINARY_D3SSD
         1
  1.000000 500.00000         2
*CONTROL_IMPLICIT_EIGENVALUE
        20     0.000         0     0.000         0     0.000         0     0.000
         0         0         0         0         1
*CONTROL_IMPLICIT_GENERAL
         1     0.000         0         0         0         0         0         0
*CONTROL_IMPLICIT_SOLUTION
         1         0         0     0.000     0.000     0.000     0.000     0.000
         2         1         1         0         2         0
         0         0     0.000         1         2
*DATABASE_HISTORY_NODE_SET
         2         0         0         0         0         0         0         0
*DATABASE_NODAL_FORCE_GROUP
        11         0
        12         0
*BOUNDARY_SPC_SET
         1         0         1         1         1         1         1         1
*SET_NODE_LIST
         1     0.000     0.000     0.000     0.000          
         1         2         3         4         5         6         7         8
         9        10        11         0         0         0         0         0
*SET_NODE_LIST
        11     0.000     0.000     0.000     0.000
         1         2         3         4         5         6         7         8
*SET_NODE_LIST
        12     0.000     0.000     0.000     0.000
         9        10        11         0         0         0         0         0
*PART
shells                                                                          
         1         1         1         0         0         0         0         0
*SECTION_SHELL
         1        18  0.833333         3         0         0         0         0
  0.005000  0.005000  0.005000  0.005000     0.000     0.000     0.000         0
*MAT_ELASTIC
         1 7830.00002.0700E+11  0.300000     0.000     0.000         0
*DEFINE_CURVE
       100         0     0.000     0.000     0.000     0.000         0
           1.0000000         100.0000000
         500.0000000         100.0000000
*DEFINE_CURVE
       200         0     0.000     0.000     0.000     0.000         0
           1.0000000               0.000
         500.0000000               0.000
*SET_NODE_LIST
         2     0.000     0.000     0.000     0.000          
         6       556         0         0         0         0         0         0
*SET_SEGMENT
*ELEMENT_SHELL
*NODE
*END


*KEYWORD  
*TITLE
A rectangular plate subjected to enforced acceleration excitation
*FREQUENCY_DOMAIN_SSD
         1        31     0.000     0.000         0         0
  0.020000         0         0     0.000     0.000
                                                           1         2         0
         1         1         3         6       100       200         0         0
*DATABASE_FREQUENCY_BINARY_D3SSD
         1
  1.000000 500.00000         2
*CONTROL_FREQUENCY_DOMAIN
            2.00e+06
*CONTROL_IMPLICIT_EIGENVALUE
        31     0.000         0     0.000         0     0.000         0     0.000
         0         0         0         0         1
*CONTROL_IMPLICIT_GENERAL
         1     0.000         0         0         0         0         0         0
*CONTROL_IMPLICIT_SOLUTION
         1         0         0     0.000     0.000     0.000     0.000     0.000
         2         1         1         0         2         0
         0         0     0.000         1         2
*DATABASE_HISTORY_NODE_SET
         2         0         0         0         0         0         0         0
*DATABASE_NODAL_FORCE_GROUP
        11         0
        12         0
*BOUNDARY_SPC_SET
         1         0         1         1         0         1         1         1
*SET_NODE_LIST
         1     0.000     0.000     0.000     0.000          
         1         2         3         4         5         6         7         8
         9        10        11         0         0         0         0         0
*SET_NODE_LIST
        11     0.000     0.000     0.000     0.000
         1         2         3         4         5         6         7         8
*SET_NODE_LIST
        12     0.000     0.000     0.000     0.000
         9        10        11         0         0         0         0         0
*PART
shells                                                                          
         1         1         1         0         0         0         0         0
*SECTION_SHELL
         1        18  0.833333         3         0         0         0         0
  0.005000  0.005000  0.005000  0.005000     0.000     0.000     0.000         0
*MAT_ELASTIC
         1 7830.00002.0700E+11  0.300000     0.000     0.000         0
*DEFINE_CURVE
       100         0     0.000     0.000     0.000     0.000         0
           1.0000000         100.0000000
         500.0000000         100.0000000
*DEFINE_CURVE
       200         0     0.000     0.000     0.000     0.000         0
           1.0000000               0.000
         500.0000000               0.000
*SET_NODE_LIST
         2     0.000     0.000     0.000     0.000          
         6       556         0         0         0         0         0         0
*SET_SEGMENT
*ELEMENT_SHELL
*ELEMENT_MASS_NODE_SET
     501       1   2.2000000e+07       0
*NODE
*END

Figures

image_001.png

image_002.png

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