Home » Knowledge Base » NVH / Fatigue » FEM acoustics with Impedance boundary conditions
A simple cabin model with seats shows how to set up multiple boundary conditions and how to define impedance boundary conditions. Example 9.4 from LS-Dyna training class NVH, Fatigue and Frequency Domain Analysis with LS-DYNA by Yun Huang.
Keywords
*CONTROL_TERMINATION
*DATABASE_BINARY_D3PLOT
*DATABASE_FREQUENCY_BINARY_D3ACS
*DEFINE_CURVE
*DEFINE_CURVE_TITLE
*ELEMENT_SOLID
*END
*FREQUENCY_DOMAIN_ACOUSTIC_FEM
*KEYWORD
*MAT_ELASTIC_FLUID
*NODE
*PART
*SECTION_SOLID
*SET_NODE_LIST
*SET_SEGMENT_TITLE
*TITLE
*KEYWORD
*TITLE
Acoustic analysis of a car cabin model by FEM
*FREQUENCY_DOMAIN_ACOUSTIC_FEM
1.2100E-12 343000.0 10.0 500.0 99 2.0e-11
0
1 0
1 2 11 3 10 30 1.
2 2 41 20 30 1.
200 1
*DATABASE_FREQUENCY_BINARY_D3ACS
1
*CONTROL_TERMINATION
0.187970 0 0.000 0.000 50.000000
*DATABASE_BINARY_D3PLOT
0.001000
0
*PART
acoustic medium
1 1 1
*SECTION_SOLID
1 10
*MAT_ELASTIC_FLUID
1 1.220000 0.000 0.000 0.000 0.000 141.03000
0.000 0.000
*SET_NODE_LIST
200 0.000 0.000 0.000 0.000
8106 20615
*DEFINE_CURVE_TITLE
Velocity
10 0 0.000 0.000 0.000 0.000 0
10.000 7.000
500.000 7.000
*DEFINE_CURVE_TITLE
Impedance
20 0 0.000 0.000 0.000 0.000 0
10.000 4.1503e-7
500.000 4.1503e-7
*DEFINE_CURVE
30 0 0.000 0.000 0.000 0.000 0
10.000 0.000
500.000 0.000
*ELEMENT_SOLID
*NODE
*SET_SEGMENT_TITLE
*SET_SEGMENT_TITLE
*END
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