Note
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MAPDL modal beam analysis example#
This example demonstrates how to perform a simple modal analysis and animate its results.
Objective#
This example models a simple 3D elastic beam made of BEAM188 elements. These beams elements are made of a linear elastic material similar to steel, and have a rectangular section.
Procedure#
Launch MAPDL instance
Material properties
Geometry
Finite element model
Boundary conditions
Solving the model
Post-processing
Stop MAPDL
Launch MAPDL instance#
Launch MAPDL with interactive plotting
from ansys.mapdl.core import launch_mapdl
nmodes = 10
# start MAPDL
mapdl = launch_mapdl()
print(mapdl)
Product: Ansys Mechanical Enterprise Academic Student
MAPDL Version: 24.2
ansys.mapdl Version: 0.68.5
Define material#
Define material
mapdl.prep7()
mapdl.mp("EX", 1, 2.1e11)
mapdl.mp("PRXY", 1, 0.3)
mapdl.mp("DENS", 1, 7800)
MATERIAL 1 DENS = 7800.000
Create geometry#
Create keypoints and line
mapdl.k(1)
mapdl.k(2, 10)
mapdl.l(1, 2)
mapdl.lplot()
Define finite element model#
Define element type/section type - Rectangular beam section.
mapdl.et(1, "BEAM188")
mapdl.sectype(1, "BEAM", "RECT")
mapdl.secoffset("CENT")
mapdl.secdata(2, 1)
# Mesh the line
mapdl.type(1)
mapdl.esize(1)
mapdl.lesize("ALL")
mapdl.lmesh("ALL")
mapdl.eplot()
mapdl.finish()
***** ROUTINE COMPLETED ***** CP = 0.000
Specify boundary conditions#
Fully fixed (clamped) end.
mapdl.solution() # Entering the solution processor.
mapdl.nsel("S", "LOC", "X", "0")
mapdl.d("ALL", "ALL")
mapdl.allsel()
mapdl.nplot(plot_bc=True, nnum=True)
Solve the model#
Setting modal analysis
mapdl.antype("MODAL")
mapdl.modopt("LANB", nmodes, 0, 200)
mapdl.solve()
mapdl.finish()
FINISH SOLUTION PROCESSING
***** ROUTINE COMPLETED ***** CP = 0.000
Postprocess#
Enter the post processor (post1)
mapdl.post1()
output = mapdl.set("LIST")
print(output)
result = mapdl.result
***** INDEX OF DATA SETS ON RESULTS FILE *****
SET TIME/FREQ LOAD STEP SUBSTEP CUMULATIVE
1 8.3233851 1 1 1
2 16.274527 1 2 2
3 50.891463 1 3 3
4 60.248510 1 4 4
5 89.208488 1 5 5
6 129.85203 1 6 6
7 138.63765 1 7 7
8 182.23482 1 8 8
Animate results
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=False,
add_text=False,
n_frames=100,
displacement_factor=normalizeDisplacement,
show_axes=False,
background="w",
movie_filename="animation.gif",
off_screen=True,
)
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[(16.153550716504107, 11.153550716504107, 11.153550716504107),
(5.0, 0.0, 0.0),
(0.0, 0.0, 1.0)]
Stop MAPDL#
mapdl.finish()
mapdl.exit()
Total running time of the script: (0 minutes 13.545 seconds)