Correlated multiple nodal forces — Welcome to LS-DYNA Examples

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This is an example of a L-shaped panel subjected to multiple nodal force power spectral density excitation. *DATABASE_FREQUENCY_BINARY_D3PSD and *DATABASE_FREQUENCY_BINARY_D3RMS are used for post-processing of the results. The effect of correlated and uncorrelated excitations can be compared. Example 6.8 from LS-Dyna training class NVH, Fatigue and Frequency Domain Analysis with LS-DYNA by Yun Huang.

Keywords

*CONTROL_IMPLICIT_EIGENVALUE
*CONTROL_IMPLICIT_GENERAL
*CONTROL_IMPLICIT_LINEAR
*CONTROL_IMPLICIT_NONLINEAR
*CONTROL_SHELL
*CONTROL_TERMINATION
*DATABASE_BINARY_D3PLOT
*DATABASE_FREQUENCY_BINARY_D3PSD
*DATABASE_FREQUENCY_BINARY_D3RMS
*DATABASE_HISTORY_NODE_SET
*DATABASE_HISTORY_SHELL_SET
*DEFINE_CURVE
*ELEMENT_SHELL
*END
*FREQUENCY_DOMAIN_RANDOM_VIBRATION
*KEYWORD  
*MAT_ELASTIC
*NODE
*PART
*SECTION_SHELL
*SET_NODE_LIST
*SET_SHELL_LIST
*TITLE


*CONTROL_IMPLICIT_EIGENVALUE
*CONTROL_IMPLICIT_GENERAL
*CONTROL_IMPLICIT_LINEAR
*CONTROL_IMPLICIT_NONLINEAR
*CONTROL_SHELL
*CONTROL_STRUCTURED
*CONTROL_TERMINATION
*DATABASE_BINARY_D3PLOT
*DATABASE_FREQUENCY_BINARY_D3PSD
*DATABASE_FREQUENCY_BINARY_D3RMS
*DATABASE_HISTORY_NODE_SET
*DATABASE_HISTORY_SHELL_SET
*DEFINE_CURVE
*ELEMENT_SHELL
*END
*FREQUENCY_DOMAIN_RANDOM_VIBRATION
*KEYWORD  
*MAT_ELASTIC
*NODE
*PART
*SECTION_SHELL
*SET_NODE_LIST
*SET_SHELL_LIST
*TITLE

Reduced Input

*KEYWORD  
*TITLE
An L-shaped panel subjected to concentrated nodal force excitation              
*FREQUENCY_DOMAIN_RANDOM_VIBRATION
         1         5     0.000     0.000         0         0 
  0.030000         0         0     0.000     0.000         0
         8         1         0     0.000         0         0         1         0
         0         0         0     0.000     0.000         0
         3         1         3      2001
*SET_NODE_LIST
         3     0.000     0.000     0.000     0.000          
       176       341       154       280
*DATABASE_FREQUENCY_BINARY_D3PSD
         1
 50.000000 1000.0000        20         0         0
*DATABASE_FREQUENCY_BINARY_D3RMS
         1
*CONTROL_IMPLICIT_EIGENVALUE
         5     0.000         0     0.000         0     0.000         0     0.000
         0         0         0         0         1
*CONTROL_IMPLICIT_GENERAL
         1  1.000000         0         0         0         0         0         0
*CONTROL_IMPLICIT_LINEAR
         0         0         1         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_SHELL
 20.000000         2        -1         0         2         2         1         0
  1.000000         0         0         1         0         0         0         0
         0         0         0
*CONTROL_TERMINATION
  1.000000         0     0.000     0.000     0.000
*DATABASE_BINARY_D3PLOT
     0.000         0         0         0         0
         0
*DATABASE_HISTORY_NODE_SET
         1         0         0         0         0         0         0         0
*DATABASE_HISTORY_SHELL_SET
         2         0         0         0         0         0         0         0
*PART
elastic L-shaped section                                                        
         1         1         1         0         0         0         0         0
*SECTION_SHELL
         1        18  0.833000         3         3         0         0         0
  0.100000  0.100000  0.100000  0.100000     0.000     0.000     0.000         0
*MAT_ELASTIC
         1 1.0000E-4 1.0600E+7  0.330000     0.000     0.000         0
*DEFINE_CURVE
      2001         0     0.000     0.000     0.000     0.000         0
          50.0000000           0.1000000
          63.0000000           1.0000000
          80.0000000           1.0000000
         100.0000000           1.0000000
         125.0000000           1.0000000
         160.0000000           1.0000000
         200.0000000           1.0000000
         250.0000000           1.0000000
         315.0000000           1.0000000
         400.0000000           1.0000000
         500.0000000           1.0000000
         630.0000000           1.0000000
         800.0000000           1.0000000
        1000.0000000           0.1000000
*SET_NODE_LIST
         1     0.000     0.000     0.000     0.000          
       176        85       241         0         0         0         0         0
*SET_SHELL_LIST
         2     0.000     0.000     0.000     0.000
        34        63         0         0         0         0         0         0
*ELEMENT_SHELL
*NODE
*END


*KEYWORD  
*TITLE
An L-shaped panel subjected to concentrated nodal force excitation              
*FREQUENCY_DOMAIN_RANDOM_VIBRATION
         1         5     0.000     0.000         0         0 
  0.030000         0         0     0.000     0.000         0
         8         1         0     0.000         0         0         4         6
         0         0         0     0.000     0.000         0
         3         1         3      2001
         4         1         3      2001
         5         1         3      2001
         6         1         3      2001
         1         2                2001
         1         3                2001
         1         4                2001
         2         3                2001
         2         4                2001
         3         4                2001
*SET_NODE_LIST
         3     0.000     0.000     0.000     0.000          
       176
*SET_NODE_LIST
         4     0.000     0.000     0.000     0.000          
       341
*SET_NODE_LIST
         5     0.000     0.000     0.000     0.000          
       154 
*SET_NODE_LIST
         6     0.000     0.000     0.000     0.000          
       280 
*DATABASE_FREQUENCY_BINARY_D3PSD
         1
 50.000000 1000.0000        20         0         0
*DATABASE_FREQUENCY_BINARY_D3RMS
         1
*CONTROL_IMPLICIT_EIGENVALUE
         5     0.000         0     0.000         0     0.000         0     0.000
         0         0         0         0         1
*CONTROL_IMPLICIT_GENERAL
         1  1.000000         0         0         0         0         0         0
*CONTROL_IMPLICIT_LINEAR
         0         0         1         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_SHELL
 20.000000         2        -1         0         2         2         1         0
  1.000000         0         0         1         0         0         0         0
         0         0         0
*CONTROL_STRUCTURED
*CONTROL_TERMINATION
  1.000000         0     0.000     0.000     0.000
*DATABASE_BINARY_D3PLOT
     0.000         0         0         0         0
         0
*DATABASE_HISTORY_NODE_SET
         1         0         0         0         0         0         0         0
*DATABASE_HISTORY_SHELL_SET
         2         0         0         0         0         0         0         0
*PART
elastic L-shaped section                                                        
         1         1         1         0         0         0         0         0
*SECTION_SHELL
         1        18  0.833000         3         3         0         0         0
  0.100000  0.100000  0.100000  0.100000     0.000     0.000     0.000         0
*MAT_ELASTIC
         1 1.0000E-4 1.0600E+7  0.330000     0.000     0.000         0
*DEFINE_CURVE
      2001         0     0.000     0.000     0.000     0.000         0
          50.0000000           0.1000000
          63.0000000           1.0000000
          80.0000000           1.0000000
         100.0000000           1.0000000
         125.0000000           1.0000000
         160.0000000           1.0000000
         200.0000000           1.0000000
         250.0000000           1.0000000
         315.0000000           1.0000000
         400.0000000           1.0000000
         500.0000000           1.0000000
         630.0000000           1.0000000
         800.0000000           1.0000000
        1000.0000000           0.1000000
*SET_NODE_LIST
         1     0.000     0.000     0.000     0.000          
       176        85       241         0         0         0         0         0
*SET_SHELL_LIST
         2     0.000     0.000     0.000     0.000
        34        63         0         0         0         0         0         0
*ELEMENT_SHELL
*NODE
*END

Figures

image_003.png

image_004.png

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