Home » Knowledge Base » NVH / Fatigue » BEM acoustics of a simplified compartment model
A simplified auto compartment model is analysed. For FFT, windowing technique raised cosine is used. Differences between collocation BEM and variational indirect BEM can be studied. Example 8.7 from LS-Dyna training class NVH, Fatigue and Frequency Domain Analysis with LS-DYNA by Yun Huang.
Keywords
*CONTROL_TERMINATION
*CONTROL_TIMESTEP
*DATABASE_BINARY_D3DUMP
*DATABASE_BINARY_D3PLOT
*DATABASE_BINARY_D3THDT
*DATABASE_BINARY_RUNRSF
*DATABASE_FREQUENCY_BINARY_D3ACS
*DEFINE_CURVE
*ELEMENT_SHELL
*ELEMENT_SOLID
*END
*FREQUENCY_DOMAIN_ACOUSTIC_BEM
*KEYWORD
*MAT_ELASTIC_FLUID
*MAT_RIGID
*NODE
*PART
*SECTION_SHELL
*SECTION_SOLID
*SET_NODE
*SET_SEGMENT
*TITLE
*KEYWORD
*TITLE
Acoustic analysis of a simplified compartment model by BEM
*FREQUENCY_DOMAIN_ACOUSTIC_BEM
1.2300E-12 3.4000E+5 10.00000 500.00000 491 0 0.0002.0000E-11
0 0 200 1 4
3 1000 1.0000E-6 8
2
1 2 0 -3
2 2 0 -2
*DATABASE_FREQUENCY_BINARY_D3ACS
1
*CONTROL_TERMINATION
0.187970 0 0.000 0.000 50.000000
*CONTROL_TIMESTEP
0.000 0.800000
0.000 0 0
*DATABASE_BINARY_D3DUMP
10000.000
*DATABASE_BINARY_D3PLOT
0.001000
0
*DATABASE_BINARY_D3THDT
5.0000E-4
*DATABASE_BINARY_RUNRSF
5000.0000
*PART
body = Al 3mm thick
1 1 1
*SECTION_SHELL
1 2
3.000000 3.000000 3.000000 3.000000
*MAT_RIGID
1 2.7000E-9 72000.000 0.300000 0.000 0.000 0.000
1.000000 7 7
0.000 0.000 0.000 0.000 0.000 0.000
*PART
acoustic medium
3 3 3
*SECTION_SOLID
3 2
*MAT_ELASTIC_FLUID
3 1.220000 0.000 0.000 0.000 0.000 141.03000
0.000 0.000
*ELEMENT_SOLID
*ELEMENT_SHELL
*NODE
*SET_NODE
200
110607
*DEFINE_CURVE
2 0 0.000 0.000 0.000 0.000 0
0.000 0.000
1000.0000000 0.000
*DEFINE_CURVE
3 0 0.000 0.000 0.000 0.000 0
0.000 7.0000000
1000.0000000 7.0000000
*SET_SEGMENT
*END
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