modal analysis

[mcMunich]

📝 Description of the example

Modal analysis of a beam.

📁 Files needed for running the example

"""
.. _ref_modal_beam:

MAPDL Modal Beam Analysis Example
---------------------

About as simple as it gets.
"""

###############################################################################
# Launch MAPDL with interactive plotting
from ansys.mapdl.core import launch_mapdl
nmodes = 10
# start MAPDL
mapdl = launch_mapdl()
print(mapdl)

mapdl.prep7()

# Define material
mapdl.mp('EX', 1, 2.1e11)
mapdl.mp('PRXY', 1, 0.3)
mapdl.mp('DENS',1, 7800)

# Define element type/section type - Rectangular beam section 
mapdl.et(1, 'BEAM188')
mapdl.sectype(1,'BEAM','RECT')
mapdl.secoffset('CENT')
mapdl.secdata(2,1)

# Create keypoints and line
mapdl.k(1)
mapdl.k(2,10)
mapdl.l(1,2)
#mapdl.lplot()

# Mesh the line
mapdl.type(1)
mapdl.esize(1)
mapdl.lesize('ALL')
mapdl.lmesh('ALL')
mapdl.eplot()
mapdl.finish()

# Enter the solution processor for boundary conditions
mapdl.run("/SOLU")
# Boundary condition (fixed end )
mapdl.nsel('S,LOC,X,0')
mapdl.d('ALL','ALL')
mapdl.allsel()
mapdl.nplot(plot_bc=True, nnum=True)
mapdl.antype('MODAL')
mapdl.modopt('LANB',nmodes,0,200)
#### Solve
mapdl.solve()
#mapdl.modal_analysis(nmode=nmodes, freqb=1)
mapdl.finish()

# Enter the post processor (post1)
mapdl.post1()
output = mapdl.set('LIST')
print(output)

result = mapdl.result

## animate result
mode2plot = 2
normalizeDisplacement = 1/result.nodal_displacement(mode2plot-1)[1].max()
result.plot_nodal_displacement( mode2plot, show_displacement=True, displacement_factor=normalizeDisplacement, n_colors=10)

result.animate_nodal_displacement(
    mode2plot,
    loop=True,
    add_text=False,
    n_frames=100,
    displacement_factor=normalizeDisplacement,
    show_axes=False,
    background="w",
    movie_filename="plane_vib.gif",
)

mapdl.finish()
mapdl.exit()

💻 Which operating system are you using?

Windows

📀 Which ANSYS version are you using?

23.2

🐍 Which Python version are you using?

3.11

📦 Installed packages

Show the Report!

```shell aiohttp==3.8.4 aiosignal==1.3.1 alabaster==0.7.13 ansi2html==1.8.0 ansys-api-mapdl==0.5.1 ansys-api-mechanical==0.1.0 ansys-api-meshing-prime==0.1.1 ansys-api-platform-instancemanagement==1.0.0b3 ansys-dpf-core==0.9.0 ansys-dpf-gate==0.4.1 ansys-dpf-gatebin==0.3.1 ansys-dpf-post==0.5.0 ansys-grpc-dpf==0.7.1 ansys-mapdl-core==0.65.2 ansys-mapdl-reader==0.52.20 ansys-mechanical-core==0.10.1 ansys-meshing-prime==0.4.0 ansys-platform-instancemanagement==1.1.1 ansys-pythonnet==3.1.0rc1 ansys-tools-path==0.3.1 anyio==3.7.1 appdirs==1.4.4 argon2-cffi==21.3.0 argon2-cffi-bindings==21.2.0 arrow==1.2.3 astroid==2.15.6 asttokens==2.2.1 async-lru==2.0.4 async-timeout==4.0.2 atomicwrites==1.4.1 attrs==23.1.0 autopep8==2.0.2 Babel==2.12.1 backcall==0.2.0 bcrypt==4.0.1 beautifulsoup4==4.12.2 binaryornot==0.4.4 black==23.7.0 bleach==6.0.0 cachetools==5.3.1 certifi==2023.5.7 cffi==1.15.1 chardet==5.1.0 charset-normalizer==3.2.0 click==8.1.4 cloudpickle==2.2.1 clr-loader==0.2.6 colorama==0.4.6 comm==0.1.3 contourpy==1.1.0 cookiecutter==2.2.3 cryptography==41.0.2 cycler==0.11.0 dash==2.13.0 dash-core-components==2.0.0 dash-html-components==2.0.0 dash-table==5.0.0 debugpy==1.6.7 decorator==5.1.1 defusedxml==0.7.1 diff-match-patch==20230430 dill==0.3.6 docstring-to-markdown==0.12 docutils==0.20.1 executing==1.2.0 fastjsonschema==2.17.1 flake8==6.0.0 Flask==2.2.5 fonttools==4.41.0 fqdn==1.5.1 frozenlist==1.4.0 geomdl==5.3.1 google-api-core==2.11.1 google-api-python-client==2.93.0 google-auth==2.22.0 google-auth-httplib2==0.1.0 googleapis-common-protos==1.59.1 grpcio==1.56.0 httplib2==0.22.0 idna==3.4 imagesize==1.4.1 importlib-metadata==6.8.0 inflection==0.5.1 intervaltree==3.1.0 ipykernel==6.24.0 ipython==8.14.0 ipython-genutils==0.2.0 ipywidgets==8.0.7 isoduration==20.11.0 isort==5.12.0 itsdangerous==2.1.2 jaraco.classes==3.3.0 jedi==0.18.2 jellyfish==1.0.0 Jinja2==3.1.2 json5==0.9.14 jsonpointer==2.4 jsonschema==4.18.2 jsonschema-specifications==2023.6.1 jupyter-events==0.7.0 jupyter-lsp==2.2.0 jupyter_client==8.3.0 jupyter_core==5.3.1 jupyter_server==2.7.0 jupyter_server_terminals==0.4.4 jupyterlab==4.0.3 jupyterlab-pygments==0.2.2 jupyterlab-widgets==3.0.8 jupyterlab_server==2.24.0 keyring==24.2.0 kiwisolver==1.4.4 lazy-object-proxy==1.9.0 MarkupSafe==2.1.3 matplotlib==3.7.2 matplotlib-inline==0.1.6 mccabe==0.7.0 mistune==3.0.1 more-itertools==9.1.0 multidict==6.0.4 mypy-extensions==1.0.0 nbclient==0.8.0 nbconvert==7.6.0 nbformat==5.9.1 nest-asyncio==1.5.6 notebook_shim==0.2.3 numpy==1.25.1 numpydoc==1.5.0 overrides==7.3.1 packaging==23.1 pandocfilters==1.5.0 paramiko==3.2.0 parso==0.8.3 pathspec==0.11.1 pexpect==4.8.0 pickleshare==0.7.5 Pillow==10.0.0 platformdirs==3.8.1 plotly==5.15.0 pluggy==1.2.0 pooch==1.7.0 prometheus-client==0.17.1 prompt-toolkit==3.0.39 protobuf==3.20.3 protoc-gen-swagger==0.1.0 psutil==5.9.5 ptyprocess==0.7.0 pure-eval==0.2.2 pyansys-tools-versioning==0.4.0 pyasn1==0.5.0 pyasn1-modules==0.3.0 pycodestyle==2.10.0 pycparser==2.21 pydocstyle==6.3.0 pyflakes==3.0.1 Pygments==2.15.1 pyiges==0.3.1 pylint==2.17.4 pylint-venv==3.0.2 pyls-spyder==0.4.0 PyNaCl==1.5.0 pyparsing==3.0.9 PyQt5==5.15.9 PyQt5-Qt5==5.15.2 PyQt5-sip==12.12.1 PyQtWebEngine==5.15.6 PyQtWebEngine-Qt5==5.15.2 python-dateutil==2.8.2 python-json-logger==2.0.7 python-lsp-black==1.3.0 python-lsp-jsonrpc==1.0.0 python-lsp-server==1.7.4 python-slugify==8.0.1 pytoolconfig==1.2.5 pyvista==0.40.1 pywin32==306 pywin32-ctypes==0.2.2 pywinpty==2.0.11 PyYAML==6.0 pyzmq==25.1.0 QDarkStyle==3.1 qstylizer==0.2.2 QtAwesome==1.2.3 qtconsole==5.4.3 QtPy==2.3.1 referencing==0.29.1 requests==2.31.0 retrying==1.3.4 rfc3339-validator==0.1.4 rfc3986-validator==0.1.1 rope==1.9.0 rpds-py==0.8.10 rsa==4.9 Rtree==1.0.1 scipy==1.11.1 scooby==0.7.2 Send2Trash==1.8.2 six==1.16.0 sniffio==1.3.0 snowballstemmer==2.2.0 sortedcontainers==2.4.0 soupsieve==2.4.1 Sphinx==7.0.1 sphinxcontrib-applehelp==1.0.4 sphinxcontrib-devhelp==1.0.2 sphinxcontrib-htmlhelp==2.0.1 sphinxcontrib-jsmath==1.0.1 sphinxcontrib-qthelp==1.0.3 sphinxcontrib-serializinghtml==1.1.5 spyder==5.4.5 spyder-kernels==2.4.4 stack-data==0.6.2 tenacity==8.2.2 terminado==0.17.1 text-unidecode==1.3 textdistance==4.5.0 three-merge==0.1.1 tinycss2==1.2.1 tomli==2.0.1 tomlkit==0.11.8 tornado==6.3.2 tqdm==4.65.0 traitlets==5.9.0 trame==3.2.4 trame-client==2.10.0 trame-components==2.1.1 trame-deckgl==2.0.2 trame-markdown==2.0.2 trame-matplotlib==2.0.2 trame-plotly==2.1.1 trame-rca==0.3.1 trame-router==2.0.2 trame-server==2.11.7 trame-simput==2.3.2 trame-vega==2.0.3 trame-vtk==2.5.4 trame-vuetify==2.2.4 typing_extensions==4.7.1 ujson==5.8.0 uri-template==1.3.0 uritemplate==4.1.1 urllib3==1.26.16 vtk==9.2.6 watchdog==3.0.0 wcwidth==0.2.6 webcolors==1.13 webencodings==0.5.1 websocket-client==1.6.1 Werkzeug==2.2.3 whatthepatch==1.0.5 widgetsnbextension==4.0.8 wrapt==1.15.0 wslink==1.11.1 yapf==0.40.1 yarl==1.9.2 zipp==3.16.1 ```

[germa89]

Thank you a lot @mcMunich !

[germa89]

Suggestions for the future implementation:

• Use mapdl.solution() instead of mapdl.slashsolu()
• Implement animations?

[mcMunich]

@germa89 Animations should be included. I just didn't have time and there are exactly 0 modal analyses on the examples page. I see that as an oversight. Also @mikerife had some preliminary ideas how to plot the secdata which is/not? currently possible. Maybe that can also be added?

[mcMunich]

@germa89 animation added above but couldn't get mapdl.solution() to work in place of mapdl.run()