Hello,
I have a problem with a simulation including non lineal material.The
problem involves a cantilever beam. The free end is moved 20 mm in X
direction. I have compared the results with Ansys. The stresses are
different, in particular at the pastification zone.
Yield point of the material
Relastic = 130 MPa,
Epsilon elastic =0.00173
The material is bilinear, it has two slopes, young 1 and young2. The slope
changes in the yield point.
The no linear material function is based on calculating …
[View More]the strains in
every cell. It is assigned the second young modulus for those strains
higher than epsilon elastic. If lower, first young modulus is set.
You can find attached the files and comparison. The picture with the
comparison has the same scale, so the colours represent the same stress
range.
My doubts are the next:
1-I am not sure if the material definition is right. Can you confirm this
for me?
2-Order of the stress strain evaluation, I set it to 3 because it provides
the closest results.
3-The output file .vtk contains only nodal solution. How to get the
elemental solution as well?
Thanks,
Jesus Sanz
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I am pleased to announce the release of SfePy 2023.2.
Description
-----------
SfePy (simple finite elements in Python) is a software for solving systems of
coupled partial differential equations by finite element methods. It is
distributed under the new BSD license.
Home page: https://sfepy.org
Mailing list: https://mail.python.org/mm3/mailman3/lists/sfepy.python.org/
Git (source) repository, issue tracker: https://github.com/sfepy/sfepy
Highlights of this release
-------------------------…
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- replace numpy.distutils by scikit-build (cmake)
- interface for the PRIMME eigenvalue problem solver
- new declarative modal analysis example
- new terms: nonlinear diffusion and nonlinear volume forces
For full release notes see [1].
Cheers,
Robert Cimrman
[1] http://docs.sfepy.org/doc/release_notes.html#id1
---
Contributors to this release in alphabetical order:
Robert Cimrman
Giuseppe Colletta
Vladimir Lukes
Yosef Meller
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Hi!
I have a tetrahedral mesh and know the nodal displacements of the mesh
from an external software.
I now want to calculate the element' strains and thought I give sfepy a
go. However, the learning curve is very steep and I struggle a bit with
this - I thought - easy task.
I thought I basically need this function here:
https://sfepy.org/doc-devel/primer.html#post-processing but how do I
initially setup the problem and set the already solved displacement vector?
This is what I got so …
[View More]far:
```
import numpy as np
from sfepy.discrete.fem import Mesh, FEDomain
from sfepy.discrete import Problem
# Given: mesh and nodal displacements
mesh = Mesh.from_file('the_mesh.vtk')
u_vec = np.random.random((mesh.n_nod, 3)) # here I would insert the
actual displacements. Use random numbers for testing
domain = FEDomain('domain', mesh)
omega = domain.create_region('Omega', 'all')
# ???
pb = Problem('elasticity', domain=domain, ...) # ???
# ???
strain = pb.evaluate('ev_cauchy_strain.2.Omega(u)', mode='el_avg')
```
Am I on the right track here?
Thanks in advance!
Best,
Sebastian
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Since the stiffness matrix (in an elastic problem, say) depends on the shape and actual locations of mesh points, conceptually it should change on each time step. Yet, solving an elastodynamic problem and printing the intermediate M, C, K matrices, they don't seem to change - though there is code called to recompute them from the nls solver (td_solvers.py get_matrices() function).
What needs to happen for the matrices to update really? Is it assumed that the mesh doesn't change much, so that …
[View More]no updates are needed?
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