mech dynamics 14.5 ws01 intro

8/12/2019 Mech Dynamics 14.5 WS01 Intro

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© 2012 ANSYS, Inc. March 28, 2013 1 Release 14.5

14.5 Release

Workshop 1

Intro. (Fly Wheel)

ANSYS MechanicalLinear and Nonlinear Dynamics




In this workshop, the vibration characteristics of a spinning flywheel will be

investigated.

Workshop 1 – Introduction




Workshop 1 – Project SchematicDrop a Static Structural system into the Project Schematic.

In this system, the rotational velocity will be applied.




Workshop 1 – Project SchematicDrop a Modal system onto the Results cell of the Static Structural system.

In this system, the prestressed modes will be found.




Workshop 1 – Project SchematicDrop a Harmonic Response system onto the Model cell of the Static Structural System.

In this system, a harmonic load will be applied to the static flywheel.


http://slidepdf.com/reader/full/mech-dynamics-145-ws01-intro 7/19© 2012 ANSYS, Inc. March 28, 2013 7 Release 14.5

Workshop 1 – UnitsIn Mechanical, set the following units system:

• mm, kg, N, s, mV, mA

• Degrees

• RPM

• Celcius



Workshop 1 – PreprocessingCreate a new cylindrical coordinate system at the global origin.

• You may want to rename the system for easy identification.



Workshop 1 – Static PreprocessingSelect the inside surface of the hub and insert a Fixed support.



Workshop 1 – Static PreprocessingInsert a Rotational Velocity inertial load.

• set the Z component to 600 RPM

Solve the model.




Workshop 1 – Static PreprocessingInsert a Directional Deformation.

• set the Coordinate System to the Cylindrical Coordinate System

The X-Axis orientation is now the radial component.




Workshop 1 – Static PostprocessingDuplicate the Directional Deformation.

• set the Orientation to Y Axis

This is now the tangential component of deformation.




Workshop 1 – Static PostprocessingUsing the cylindrical coordinate system again, insert radial and tangential components of

stress.




Workshop 1 – Modal PostprocessingMove down to the Modal branch and Solve.

Insert total deformation plots to review the mode shapes.

• Highlight all rows in the frequency table.

• Right click and Create Mode Shape Results.




Workshop 1 – Harmonic PreprocessingInsert an Acceleration inertial load.

• set the Z component to 2 G (~20000 mm/s^2)




Workshop 1 – Harmonic SolutionSettings

Modify the Analysis Settings.

• set the Range Maximum to 500 Hz

• set Cluster Results to Yes

• set Constant Damping Ratio to 5%

Solve the model.




Workshop 1 – Harmonic PostprocessingInsert a Deformation Frequency

Response result on the outer

surface of the flywheel.• set the Spatial Resolution to Use

Maximum

• set the Orientation to Z Axis

Make note of the frequency andphase angle at which the

maximum amplitude occurs.




Workshop 1 – Harmonic PostprocessingInsert a Directional Deformation result.

• set the Orientation to Z Axis

• use the frequency and phase angle for the maximum amplitude, noted from the previous slide (~240Hz @ 93°)

mech dynamics 14.5 ws01 intro

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