General
Home / Examples / Stress Analysis [Galileo] / Example 12: Resonance of Metal Bars
The model consists of three metal bars. The resonance is analyzed.
The deformation, the displacement distribution, and the stress distribution are solved.
Unless specified in the list below, the default conditions will be applied.
Results will vary depending on Femtet version and the PC environment.
Item |
Settings |
Analysis Space |
3D |
Model Unit |
m |
The analysis type is the harmonic analysis.
Item |
Settings |
Solver |
Stress Analysis [Galileo] |
Analysis Type |
Resonant Analysis |
Options |
N/A |
The resonant analysis tab is set up as follows.
Tab |
Setting Item |
Settings |
Resonant Analysis |
Number of Modes |
6 |
Approximated Frequency |
0 [Hz] |
Three metal bars and two support rods are created as box-shape solid body.
The bottom faces of support rods are fixed with the displacement boundary condition.
Body Number/Type |
Body Attribute Name |
Material Name |
0/Solid |
RESONANT |
001_Al * |
1/Solid |
RESONANT |
001_Al * |
2/Solid |
RESONANT |
001_Al * |
8/Solid |
BASE |
M_BASE |
9/Solid |
BASE |
M_BASE |
* Available from the material DB
The material properties are set up as follows:
Material Name |
Tab |
Properties |
M_BASE |
Elasticity |
Young's Modulus: 2×109 [Pa] Poisson's Ratio: 0.3 |
Density |
Density: 0.1x103 [Kg/m3] |
The bottom faces of support rods are fixed with the displacement boundary condition.
Boundary Condition Name/Topology |
Tab |
Boundary Condition Type |
Settings |
FIX/Face |
Mechanical |
Displacement |
Select all X/Y/Z components. UX=0, UY=0, UZ=0 |
The following will be output on the output window.
<<Eigenvalue analysis>> Eigenvalue (resonant frequency):[Hz] Mode[ 0] = 8.61552809e+002 Mode[ 1] = 1.06874655e+003 Mode[ 2] = 1.21598202e+003 Mode[ 3] = 1.24695787e+003 Mode[ 4] = 1.56876049e+003 Mode[ 5] = 1.69339225e+003 |
The resonant frequencies can be checked on Table.
The displacement diagrams of Mode[0] to Mode[ 2] are shown below.
The contours are the Z displacement.
The minimum and maximum values are manually set to
-4.000e+000 and 4.000e+000 respectively.
Mode[0]:8.615528e+002 [Hz]
Mode[1]:1.068747e+003 [Hz]
Mode[2]: 1.215982e+003 [Hz]
The shorter bar exhibits the higher resonant frequency.