Fatigue analysis based on SSD — Welcome to LS-DYNA Examples

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This is a simplified bumper model with base acceleration. It shows how to fatigue analysis for sine sweep testing with *FREQUENCY_DOMAIN_SSD_FATIGUE and how to postprocess with *DATABASE_FREQUENCY_BINARY_D3SSD and *DATABASE_FREQUENCY_BINARY_D3FTG. Example 5.5 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_NONLINEAR
*DATABASE_FREQUENCY_BINARY_D3FTG
*DATABASE_FREQUENCY_BINARY_D3SSD
*DEFINE_CURVE
*ELEMENT_SOLID
*END
*FREQUENCY_DOMAIN_SSD_FATIGUE
*KEYWORD
*MAT_ADD_FATIGUE
*MAT_ELASTIC
*NODE
*PART
*SECTION_SOLID
*SET_NODE_LIST

Reduced Input

*FREQUENCY_DOMAIN_SSD_FATIGUE
         1        15        0.    90000.         0                             
      0.03

                             3         3      2001                2002
*DATABASE_FREQUENCY_BINARY_D3SSD
         1
     200.0    1500.0        14
*DATABASE_FREQUENCY_BINARY_D3FTG
         1
*MAT_ADD_FATIGUE
       227       400
*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_IMPLICIT_EIGENVALUE
        15     0.000         0     0.000         0     0.000         0     0.000
         0         0         0         0         1
*BOUNDARY_SPC_SET
         1         0         1         1         1         1         1         1
*DEFINE_CURVE
      2001         0  1.000000       1.0     0.000     0.000         0
          100.000000            9.81E+03
          2000.00000            9.81E+03
*DEFINE_CURVE
      2002         0  1.000000       1.0     0.000     0.000         0
          100.000000            6.00E+02
          2000.00000            6.00E+02
*DEFINE_CURVE
       400
                8000              1.e+02
               80000              1.e+01
              800000              1.e+00
             8000000              1.e-01
            80000000              1.e-02
           800000000              1.e-03
          8000000000              1.e-04
*DEFINE_CURVE
        14         0       0.0       0.0       0.0       0.0         0         0
                 0.0               0.896
                0.19               0.896
                 0.8               0.897
                0.81               140.0
                0.84               222.8
*ELEMENT_SOLID
*NODE
*SET_NODE_LIST
*PART
f_ob_bumper_ft_foam
       227       227       227         0         0         0         0         0
*SECTION_SOLID
       227        18         0
*MAT_ELASTIC
       227 1.475E-09   20700.0       0.3
*END

Figures

image_005.png

image_006.png

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