Ansys Mechanical Modal B

download Ansys Mechanical Modal B

of 12

  • date post

    08-Sep-2015
  • Category

    Documents

  • view

    240
  • download

    3

Embed Size (px)

description

Plate with a hole

Transcript of Ansys Mechanical Modal B

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

    14.5 Release

    Workshop 4A Modal Analysis (Plate with a Hole)

    ANSYS Mechanical Linear and Nonlinear Dynamics

  • 2012 ANSYS, Inc. March 28, 2013 2 Release 14.5

    Workshop 4A - Goals

    Our goal is to determine the first 10 natural frequencies and mode shapes for the plate with the hole shown.

    The plate is made of Aluminum.

    Assume the plate is fully constrained at the hole.

    As if the plate is tightly bolted down at the hole.

    Fixed Center

  • 2012 ANSYS, Inc. March 28, 2013 3 Release 14.5

    Workshop 4A Project Schematic

    From the project schematic, insert a new Modal system.

    Import the Geometry file

    plate.iges

  • 2012 ANSYS, Inc. March 28, 2013 4 Release 14.5

    Workshop 4A - Preprocessing Edit the Engineering Data cell.

    add Aluminum Alloy from the General Materials library to Engineering Data

  • 2012 ANSYS, Inc. March 28, 2013 5 Release 14.5

    Workshop 4A - Preprocessing Return to the Project

    Edit the Model cell to open the Mechanical application

  • 2012 ANSYS, Inc. March 28, 2013 6 Release 14.5

    Workshop 4A Units In Mechanical, set the following units system:

    in, lbm, lbf, F, s, V, A Degrees RPM

  • 2012 ANSYS, Inc. March 28, 2013 7 Release 14.5

    Workshop 4A - Preprocessing Set the plate thickness to 0.1 in

    Set the plate material assignment to Aluminum Alloy

  • 2012 ANSYS, Inc. March 28, 2013 8 Release 14.5

    Workshop 4A - Environment Constrain the center hole.

    highlight the Modal Branch to >Insert>Fixed Supports.

    Switch to edge selection mode as necessary

    Use Box Select, or drag single-select LMB around the hole to pick all applicable edge segments (4 edges)..

    Click Apply in the Details window Reorient model as necessary throughout.

    9

    8

  • 2012 ANSYS, Inc. March 28, 2013 9 Release 14.5

    Workshop 4A Modal Solution Check the Details of Modal Analysis Settings.

    set Max Modes to Find to 10 set Calculate Stress Yes set Calculate Strain Yes

    If you just want frequencies and shapes, you dont need to calculate stress or strain. It will save a little time to skip those calculations.

    Solve the Modal analysis.

  • 2012 ANSYS, Inc. March 28, 2013 10 Release 14.5

    Workshop 4A - Results After the modal solution is completed, review the modal shapes for each frequency.

    Click on the Modal Solution Branch in the Tree. Then LMB on the top of the Frequency Column in the Tabular Data region, and >RMB>Create Mode Shape Results

    This will automatically insert Total Deformation objects in the Tree for all modes solved.

  • 2012 ANSYS, Inc. March 28, 2013 11 Release 14.5

    Workshop 4A - Results

    To get an overall view of the Modal results step thru (LMB) the Total Deformation result objects for each mode.

    You can also Animate (Play & Stop) the mode from the Timeline window.

  • 2012 ANSYS, Inc. March 28, 2013 12 Release 14.5

    Workshop 4A - Comments Remember:

    Displacements reported with mode shapes are relative and do not reflect the actual max magnitudes of the displacements. The actual magnitudes will depend on the energy input to the system (depends on forcing function).

    Sometimes it is challenging to visualize the true mode shape from a simple contour plot.

    Try the Vector Display instead. Adjust the Vector Scale slider as desired.

    You can also animate the vector plot too.

    Contour

    Plot.

    Difficult to

    determine

    deformation

    directions

    Vector

    Plot

    Arrows may

    be more

    intuitive in

    some cases.