Home / Examples / Stress Analysis [Galileo] / Example 11: Resonance of Church Bell

Example 11: Resonance of Church Bell

General

• The resonance of a church bell is analyzed.
   

• The deformation, the displacement and the stress are solved.
   

• Unless specified in the list below, the default conditions will be applied.
   

• Obtain this session's project file. (Right-click and choose 'Save link as')




• Results will vary depending on Femtet version and the PC environment.

 

Analysis Space

Item	Settings
Analysis Space	3D
Model Unit	m

 

Analysis Conditions

The analysis type is the resonant 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]

Model

Two spherical solid bodies and two cylindrical solid bodies are created, first. The smaller sphere and cylinder, and the larger sphere and cylinder are united by boolean respectively.

The smaller object is subtracted from the larger one. As a result, a church bell is created.

Body Attributes and Materials

Body Number/Type	Body Attribute Name	Material Name
10/Solid	BELL	008_Cu *

* Available from the material DB

Boundary Conditions

N/A

Results

The following will be output on the output window or the log file.

<<Eigenvalue analysis>> Eigenvalue (resonant frequency):[Hz] Mode[ 0] = 8.61317565e+001 Mode[ 1] = 8.61493565e+001 Mode[ 2] = 2.25520570e+002 Mode[ 3] = 2.26128750e+002 Mode[ 4] = 3.22020390e+002 Mode[ 5] = 3.22035453e+002

 

The resonant frequencies can be checked on Table.

 

 

The fundamental resonant frequency is 86.1 [Hz].

There are two degenerated fundamental resonant modes, which are Mode[0] and Mode[1].

 

The displacement of fundamental Mode[0] is as below. The contour diagram shows the magnitude of displacement.

 

The displacement of the high-order mode, Mode[2], is shown below. The contour indicates the magnitude of the displacement.

The number of nodes is 4 for the fundamental mode, whereas it is 6 for the higher-order mode.