Bone remodeling: Komarova model
Dear Community,
I make a code public for bone remodeling, using the Komarova model. It was developed by me alone. I provide the code as is, without warranty.
Frank Richter's blog
reflection and transmission coefficients in long elastic bars
Dear iMechanica Community,
I'd like to ask for advice on modelling reflection and transmission coefficients when two bars with different cross-sectional areas contact each other and are exposed to pulse loading.
I have modelled this process in Abaqus/Explicit as a two-dimensional simulation. The investigation was conveniently done as a parametric study, defining the lateral dimension as parameter. Both bars are slim (length 2 m, diameter 2 cm) and elastic.
UMAT for Zener model and Kelvin-Voigt model
Dear iMechanica community,
you can find the UMAT-implementation of a Zener model, i.e. a Maxwell model parallel to a spring, in my PhD thesis:
“Upsetting and Viscoelasticity of Vitreous SiO2: Experiments, Interpretation and Simulation“
Technische Universitaet Berlin, Germany, 2006
https://depositonce.tu-berlin.de/handle/11303/1574
http://dx.doi.org/10.14279/depositonce-1277
ABAQUS built-in material models
Dear Mechanicians,
ABAQUS has a number of little-known built-in material models that are not documented in the manuals.
They are accessible from https://www.3ds.com, follow the path "Support", "Knowledge Base" and search for "Built-in user material models for Abaqus/Standard and Abaqus/Explicit". Below is a text version of the output.
It may be that you need special rights on the site; these can be requested from your regional SIMULIA HQ.
Subroutine DFLUX in ABAQUS
Dear Mechanicians,
time and again the question of modeling moving heat sources pops up, often in the context of laser heating.
One can achieve this using the subroutine DFLUX in ABAQUS.
I decided to post some links here to avoid responding with a longer explanation to every individual seeking assistance.
Please note that I have never worked with any one of these codes and have no access to ABAQUS at present.
No warranty is given by me.
"ELEMENT DELETION" is available in Abaqus Explicit:
ABAQUS built-in SMA model
Dear Mechanicians,
time and again the question of SMA (shape memory alloy) modeling pops up.
In ABAQUS, you can achieve this only by (V)UMAT coding or by using the little-known built-in SMA model.
In the past I have frequently responded to queries on SMA modeling and could refer to a customer help site of SIMULIA. That site is down, regrettably.
I decided to post the files here to avoid responding with a longer explanation to every individual seeking assistance and uploading the files as E-mail attachment every time.
Uniaxial compression of heterogeneous/cellular material (bone)
Dear colleagues,
I kindly ask for advice on the following problem:
I simulate the uniaxial compression of a heterogeneous cylinder representing bone. Thus, it is not the visible solid exterior rim of the bone, but represents a porous structure within the bone, so-called trabecular bone, see the figure underneath.
The simulation is done in ABAQUS. The sample contains 164175 elements of type C3D4. The heterogeneous, porous structure makes it impossible to use axisymmmetric elements. The constitutive behavior is ELASTIC.
Inverse problem in beam bending, elastic-ideally plastic material
Dear iMechanica,
suppose you have a beam with a square cross-section, manufactured from an elastic-ideally plastic material.
Now apply a load that rises linearly in time, but is locally constant along the beam length. Upon sagging, the beam will develop a plastic zone beginning in the top and surface regions at mid-length.
This is the "straight" problem solved in Prager, Hodge: Theory of perfectly plastic solids, publisher: Springer