Add FreeVibration(items, boundaries)

[adtzlr]

with methods to evaluate() and extract() the n-th eigenvector to a field.

Tasks

• check for mixed-field solid bodies
• test the performance for typical (10^5) degrees-of-freedom models

Example

import felupe as fem

mesh = fem.Rectangle(b=(5, 1), n=(50, 10))
region = fem.RegionQuad(mesh)
field = fem.FieldContainer([fem.FieldPlaneStrain(region, dim=2)])

boundaries = dict(left=fem.Boundary(field[0], fx=0))
solid = fem.SolidBody(umat=fem.LinearElastic(E=2.5, nu=0.25), field=field, density=1.0)

res = fem.FreeVibration(items=[solid], boundaries=boundaries).evaluate()
field, frequency = res.extract(n=4, inplace=True)

ax = solid.imshow("Stress", component=0)
ax.set_title(rf"Frequency $f_5$ = {frequency:.2} Hz")

[adtzlr]

This is also possible

import felupe as fem

meshes = [
    fem.Cube(a=(0, 0, 30), b=(50, 100, 35), n=(6, 11, 2)),
    fem.Cube(a=(0, 0, 5), b=(50, 100, 30), n=(6, 11, 6)),
    fem.Cube(a=(0, 0, 0), b=(50, 100, 5), n=(6, 11, 2)),
]
container = fem.MeshContainer(meshes, merge=True)
mesh = container.stack()

regions = [fem.RegionHexahedron(m) for m in container.meshes]
fields = [
    fem.FieldsMixed(regions[0], n=1),
    fem.FieldsMixed(regions[1], n=3),
    fem.FieldsMixed(regions[2], n=1),
]

region = fem.RegionHexahedron(mesh)
field = fem.FieldContainer([fem.Field(region, dim=3), fields[1][1], fields[1][2]])

boundaries = dict(left=fem.Boundary(field[0], fx=0))
rubber = fem.ThreeFieldVariation(fem.NeoHooke(mu=1, bulk=5000))
steel = fem.LinearElasticLargeStrain(2.1e5, 0.3)
solids = [
    fem.SolidBody(umat=steel, field=fields[0], density=7.85e-9),
    fem.SolidBody(umat=rubber, field=fields[1], density=1.5e-9),
    fem.SolidBody(umat=steel, field=fields[2], density=7.85e-9),
]

job = fem.FreeVibration(solids, boundaries).evaluate(x0=field)

import matplotlib.pyplot as plt

fig, ax = plt.subplots(figsize=(10, 2), ncols=3)

for n in range(3):
    f, frequency = job.extract(x0=field, n=n, inplace=False)
    ax[n] = f.imshow(show_undeformed=False, factor=10 / f[0].values.max(), ax=ax[n])
    ax[n].set_title(r"Frequency $f" + f"_{n+1}$ = {frequency:.0f} Hz")

[codecov]

Codecov Report

Attention: Patch coverage is 98.33333% with 1 line in your changes missing coverage. Please review.

Project coverage is 97.30%. Comparing base (e2305db) to head (95c965d).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/felupe/mechanics/_free_vibration.py	97.95%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #909   +/-   ##
=======================================
  Coverage   97.30%   97.30%           
=======================================
  Files         179      180    +1     
  Lines        6337     6393   +56     
=======================================
+ Hits         6166     6221   +55     
- Misses        171      172    +1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.