Home » Knowledge Base » NVH / Fatigue » BEM acoustics of a beam subjected to SSD
A rectangular beam is subjected to frequency domain acceleration. BEM acoustic analysis is coupled with SSD excitation via *FREQUENCY_DOMAIN_SSD. *FREQUENCY_DOMAIN_ACOUSTIC_BEM uses variational indirect BEM and raised cosine windowing technique for FFT. In the file domgeom.k the domain decomposition can be studied. Example 8.4 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_BINARY_D3SSD
*DATABASE_HISTORY_NODE_SET
*DEFINE_CURVE
*ELEMENT_SHELL
*END
*FREQUENCY_DOMAIN_ACOUSTIC_BEM
*FREQUENCY_DOMAIN_SSD
*KEYWORD
*MAT_ELASTIC
*NODE
*PART
*SECTION_SHELL
*SET_NODE_LIST
*SET_SEGMENT
*TITLE
*KEYWORD
*TITLE
A rectangular plate subjected to nodal 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_BINARY_D3SSD
1
1.000000 500.00000 500 0 0
*FREQUENCY_DOMAIN_ACOUSTIC_BEM
1.210000 340.00000 1.000000 500.00000 500 0.001000 0.000 2.0000E-5
3 1 0 0 4 0 0 0
2 1000 1.0000E-6 8 0.000 0.000 0 0
1 1
1 2 0 0
*CONTROL_IMPLICIT_EIGENVALUE
20 0.000 0 0.000 0 0.000 0 0.000
0 0 0 0
*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
*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
*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_NODE_LIST
3 0.000 0.000 0.000 0.000
1001 0 0 0 0 0 0 0
*SET_SEGMENT
*ELEMENT_SHELL
*NODE
*END
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