Kevin Moerman 🔓🦿:julia:

Working on automated parameterised meshing of #FiniteElementAnalysis of periodic auxetic structures.

#Julialang #ComputationalMechanics #ComputationalDesign #Comodo #opensource

More on auxetic structures:
https://en.wikipedia.org/wiki/Auxetics

Built using the Comodo project:
https://github.com/COMODO-research/Comodo.jl

Working on nested triply periodic lattices. Here a Gyroid levelset image is created and two interwoven/complementary surfaces are obtained by constructing isosurfaces for the same positive (white) or negative level (red). In the animation the levelset level is adjusted so the surfaces "shrink away" from each other.

More on Gyroids: https://en.wikipedia.org/wiki/Gyroid)

Coming soon to #Comodo #Julialang #opensource

#ComputationalMechanics #ComputationalDesign

Playing with #FiniteElementAnalysis of an "expansion mesh" like structure. The geometry, mesh and boundary condition creation, as well as the FEA analysis, all occur automatically.

This simulation is still elastic, next step is to add plasticity.

#ComputationalMechanics #GIBBON

Working on extruding or "thickening" meshes from surface elements to layers of solid elements. Here the test mesh features quads (left) which are thickened to produce hexahedral elements (right).

This is especially handy when one wants a high quality structured mesh of a thin structure. For instance meshing of blood vessel like structures.

#Comodo #JuliaLang #ComputationalMechanics #ComputationalDesign

TetGen functionality has now been added to Comodo.

Demo: https://github.com/COMODO-research/Comodo.jl/blob/main/examples/demo_tetgenmesh.jl

#JuliaLang #opensource #computationaldesign #computationalmechanics

Went with another classic, the dragon statue.

This shows triangulated surface remeshing using a (very basic) #JuliaLang wrapper for @BrunoLevy01 et al.'s fantastic Geogram library (https://github.com/BrunoLevy/geogram).

#GeometryProcessing #Meshing #ComputationalMechanics #ComputationalDesign

Coming soon to #comodo: constrained #Delaunay triangulations. Which I decided needs parameterized #Batman curves too for testing purposes 🦇

#julialang #GeometryProcessing #meshing #ComputationalDesign

So satisfying to finally reach 100% code coverage for testing!

Hoping to publish paper on Comodo by the end of the year. If you are into #ComputationalMechanics #Biomechanics #GeometryProcessing #FiniteElementAnalysis help to contribute to Comodo.jl and FEBio.jl and you'll be one of the authors!

https://github.com/COMODO-research/Comodo.jl

#julialang #opensource #ContinuousIntegration #CodeCov

Interesting paper by @jedbrown et al.

https://doi.org/10.48550/arXiv.2401.13196

For computational mechanics/physics, if you code by just punching in the equations from the textbooks directly, the physics should work, but computationally the way you evaluate the quantities may be unstable. This paper lists some recipes to avoid these.

Mostly small strain problem, but still feels icky to leave in.

#FiniteElementMethod #FiniteElementAnalysis

#FEBio @mofem @likask #Ferrite @koehlerson

Just a bit of #julialang looking ridiculously awesome :)

Based on #Ferrite by @koehlerson et al. https://ferrite-fem.github.io/Ferrite.jl/stable/

#FiniteElementAnalysis

And say hello to Gibbon.jl, ongoing work towards a #JuliaLang implementation of the MATLAB toolbox GIBBON (https://www.gibboncode.org/. )

First pass at Gibbon.jl
https://github.com/gibbonCode/Gibbon.jl/

#opensource #openscience #FiniteElementAnalysis #ComputationalMechanics #biomechanics

Here is my first pass at this #JuliaLang wrapper for #FEBio:
https://github.com/febiosoftware/FEBio.jl

#opensource #openscience #FiniteElementAnalysis #ComputationalMechanics #Biomechanics

Sneak peek at my #JuliaLang wrapper for #FEBio, an advanced #FiniteElement solver for #ComputationalMechanics and #Biomechanics

More on FEBio here:
https://febio.org/
https://github.com/febiosoftware/FEBio

Just read about "rabbit functions", a term for math expressions that are essentially "pulled out of a hat"! Love it, and have to use this in a paper some day.

From "Wachspress 1975, A Rational Finite Element Basis:

"A "rabbit function" is a function that is pulled out of a hat. When a magician pulls a rabbit out of a hat, the effect astonishes the onlookers. Once the illusion is revealed, the rabbit generation is
no more surprising than the generation of rabbits by rabbits."

#FiniteElement

New #preprint : "Experimental and Computational Analysis of Energy Absorption Characteristics of Three Biomimetic Lattice Structures Under Compression" https://arxiv.org/abs/2308.14452
#finiteelementanalysis #biomechanics #lattice

Added textured OBJ model import to GIBBON. The OBJ import supports mixed faces (e.g. tri+quads).
The demo video shows coupled refinement of both the geometry and texture data for an imported model.

Also useful for resampling digital image correlation data on 3D surfaces.

#GeometryProcessing #meshing #3dmodel #opensource

Saw a paper on a soft robotic star thing, and had to check. Yep I can confirm, it looks like it can grab things.

Paper: https://doi.org/10.1002/aisy.202200435

#opensource #FiniteElementAnalysis

Here is a link to my fully parameterized implemention with #FEBio + #GIBBON: https://www.gibboncode.org/html/DEMO_febio_0085_soft_robotic_star_01.html

GIBBON is ready for #CMBBE2023 ! Heading to Paris tomorrow and can't wait to present the latest implementations and upgrades for FEBio4.

If you are attending the workshop, upgrade GIBBON to the latest version:
https://www.gibboncode.org/

#opensource #biomechanics #FiniteElementAnalysis #ComputationalMechanics #MechanicalEngineering

https://www.cmbbe-symposium.com/2023/workshops/

#opensource #GeometryProcessing #meshing #finiteelementanalysis

In case you want your tongue #FiniteElement Model to go eeeewwww. This GIBBON demo features active contraction of mapped "muscle fibers".

I just updated it for FEBio4.

#opensource #biomechanics

https://www.gibboncode.org/html/DEMO_febio_0024_active_contraction_tongue.html

Checking out "Taubin" smoothing. Looks great for smoothing voxel derived meshes. Video shows voxel mesh (red) of a femur and the Taubin smoothed surface retrieved (white).

One of Taubin's papers: https://doi.org/10.1109/ICCV.1995.466848

#opensource GIBBON implementation: https://www.gibboncode.org/html/HELP_smoothTaubin.html

#biomechanics #FiniteElementAnalysis #meshing #GeometryProcessing

Here the strain that you think you are applying (red curve) and the real strain in the middle layer (green curve) are plotted over time. As you can see a compressive Z-strain builds up during clamping which may offset the strain graph a lot.
Note this is Green-Lagrange strain. The linear tensile strain intended to be applied is 30%, the linear clamping strain is -30%.

#opensource #FiniteElementAnalysis

https://www.gibboncode.org/html/DEMO_febio_0065_clamp_tension_test.html

Indentation with a twist.

The rigid ball pushes into the rubber-like hyperelastic cube while also spinning. Friction then transfers torsional forces to the cube as well.

#opensource #GIBBON #FEBio #FiniteElementAnalysis
https://www.gibboncode.org/html/DEMO_febio_0028_sphere_indentation_friction_twist.html

New #openaccess #preprint with collaborators Shaiv Parikh et al.

"Biomechanical characterisation of thoracic ascending aorta with preserved pre-stresses"

https://doi.org/10.1101/2022.12.02.518810

Features some lovely automated meshing and #FiniteElementAnalysis with GIBBON

A ridiculous #FiniteElement model for whoever wants to simulate a rubbery propeller hitting a stick.

I just used this to play with a contact algorithm and was curious to see if it would work.

#opensource: https://www.gibboncode.org/html/DEMO_febio_0040_propeller_contact.html

Here is a nice review paper on: "What Kelvin might have written about Elasticity"
https://doi.org/10.1111/j.1365-2478.2011.01049.x

And more on benefits for use with #FiniteElementAnalysis:
https://arxiv.org/pdf/1605.09606

A simple demo for automated design, meshing and #FiniteElementAnalysis of a hyperelastic tire in contact with a road surface.

#opensource GIBBON implementation: https://www.gibboncode.org/html/DEMO_febio_0079_tire_load_01.html

Lovely new paper by PhD student I co-supervise: Mahtab Vafaeefar (Twitter: @MahtabVfa)

Have a look if you are into: lattice structures, trabecular bone, #biomechanics and/or #FiniteElementAnalysis

"A Morphological, Topological and Mechanical Investigation of Gyroid, Spinodoid and Dual-Lattice Algorithms as Structural Models of Trabecular Bone"

#openaccess link
https://arxiv.org/abs/2211.13036

Journal link
https://doi.org/10.1016/j.jmbbm.2022.105584

Uses #opensource GIBBON codes for lattice structure+model creation

Automated meshing of a bifurcation (e.g. for blood vessel #FiniteElementAnalysis) with hexahedral elements using #opensource #GIBBON toolbox.

1) Take a cylinder
2) Cut a hole at bifurcation curve
3) Create direction vectors for surface "departure and arrival"
4) Use smooth bezier spline based lofting
5) Thicken quads to form hex. elements.

Demo rendered here:
https://www.gibboncode.org/html/DEMO_mesh_bifurcation_cut_loft_branch.html

Bezier approach was inspired by @acegikmo 's spline work