Example14 Resonance of Cantilever

General

  • The resonance of a cantilever is analyzed. Unlike Exercises 11 through 13,
    one end is fixed with the displacement boundary condition.
     

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

  • The directional sensitivity due to the participation factor and the effective mass can be examined for obtained modes.
     

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

 

Analysis Space

Item

Settings

Analysis Space

3D

Model unit

mm

 

Analysis Conditions

The analysis type is the harmonic analysis.

Item

Settings

Solvers

Mechanical 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

3

Approximated frequency

0[Hz]

Model

The cantilever is created as a box-shape solid body.

The material is silicon. One end is fixed with the displacement boundary condition.

Body Attributes and Materials

Body Number/Type

Body Attribute Name

Material Name

0/Solid

LEVER

301_Silicon(single-crystal) *

* Available from the Material DB

Boundary Conditions

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

 

Results

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

<<Eigenvalue analysis>>

Eigenvalue (resonant frequency):[Hz]

Mode[0]= 2.50953498e+004

Mode[1]= 1.65669006e+005

Mode[2]= 3.22935422e+005

 

The resonant frequencies can be checked on Table.

 

 

The displacement diagram of Mode[0] is shown below. The contour is the Z displacement.

 

The displacement diagram of Mode[1] is shown below. The contour is the Z displacement.

 

The effective mass ratio graph can be output from [Table].

 

 

UZ component (the effective mass ratio in Z direction) is 62.0[%] at Mode 0, 18.4[%] at Mode 1 and 0[%] at Mode 2.

Mode 0 is the main mode.

The accumulated value is 80.4[%].

If more modes are calculated, it will approach 100[%].

 

As for UX and UY components, the main modes are not obtained yet.

You need to calculate more modes.